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Vessel Specification

The 32' Steel Tug-Yacht, TERRIER

32' Tug Yacht - TERRIER - Kasten Marine Design, Inc.

Terrier Outboard Profile | Terrier Interior P & A | Perspective Forward | Perspective Aft

Copyright 1995 - 2016 Michael Kasten

The following is provided as a sample Vessel Specification. It is for a small 32' tug-yacht, intended for amateur building.

Our usual Vessel Specification for boats over 40' length on deck will amount to some 50 to 80 pages, and will therefore be much more detailed than what follows. The overall concept surrounding the design of the 32' Terrier is 'small and simple' - very much in keeping with my notion of Nomadic Watercraft. The pursuit of simplicity onboard the Terrier applies to all systems, and is therefore reflected in the relatively basic Vessel Specification that follows.


The Tug-Yacht Terrier was designed for a Puget Sound, Washington boat builder who wanted to offer a fabricated bare hull "kit." The concept for Terrier was to create the ideal small family power vessel for amateur construction, whether starting from only the plans and a delivery of steel, or alternately if starting from a pre-built bare hull.

Yet another option would be to take delivery of a "power-away" boat, with engine and steering functional, and all exterior hatches, windows and doors installed. This would be fairly quick and economical for an owner to finish out. In any case, Terrier is small and simple enough to be easily built.

More information about boat building costs can be found at our web page on Affordable Boatbuilding, and among the web pages linked from there.


This Vessel Specification is the central document from which the Motor Vessel Terrier will be built. It is the intent of this Vessel Specification to assure that the vessel's trim, stability, systems, structure, and the vessel's behavior, performance, and safety be as designed by Kasten Marine Design, Inc., and that the features of the yacht be as planned by the owner.

Rather than being an explanation of how to build Terrier, this Vessel Specification is intended to explain what to build. Information is provided about the scantlings, materials of construction and other relevant information that is not found in the Building Plans.

Tug Yacht - TERRIER - Kasten Marine Design, Inc.
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General Concept

The intent of the Terrier design has been to create a small coastwise and offshore power yacht in steel, able to do occasional light towing for fun, and with the additional requirement of being a capable long range ocean voyager. The hull is designed after that of a working tug in order to get the most boat within the smallest overall length, thus having a plumb bow and not too much overhang aft. Unlike a working tug however, the lines have been refined in order to provide an easily driven hull. Terrier's stability range is especially large for a power vessel, and the sectional shape is designed for an easy motion.

Particulars are: 32' LOA x 28' LWL x 11' Beam x 3' 8" Draft. Having a design displacement of 15,500# Terrier is of "medium" displacement, at D/L 319. Displacement will vary from around 14,750# lightly loaded, to a maximum load of 19,500# with tanks full, stores for two people, and the boat ready for a long cruise.

Steel used will be A-36 mild steel. 'Cor-ten' steel can be used if so desired, and it will provide approximately 50% higher yield strength allowing the plating to be more easily kept fair while building. 'Cor-ten' is simply a brand name for one of the High Strength Low Alloy (HSLA) steels that have reduced carbon content and small additions of other metals to improve strength while retaining excellent ductility. More information about HSLA steels on our web page about Metal Boats for Blue Water.

Construction materials will be as follows:

Optionally, Terrier can be built in all aluminum, in which case the entire exterior of the Hull, Decks, Houses and House Tops would be built in aluminum.

The cabin structures provide standing headroom of over 6' on centerline throughout. The exterior main deck has a small deck-well to starboard that permits the Pilot House door to be of a reasonable height. The Fore Deck steps up to the top of the bulwark just forward of the Pilot House door to Starb'd, and also to Port at the same fore and aft location. There is no deck well to Port.

The Aft Deck is surrounded by a substantial bulwark for maximum safety, and the Fore Deck is surrounded by a toe rail. Although not shown on the drawings, the decks are to be additionally protected by a 32" high welded stern pulpit and welded stanchions with life lines along both side decks. Wooden hand rails will be provided on each house top.

There will be a manual vertical axis windlass on the fore deck, and one large substantial bitt on the after deck. Additional bitts and cleats will be provided for mooring and anchoring. All deck hardware will be steel and will be integrally fabricated as part of the hull.

Tug Yacht - TERRIER - Kasten Marine Design, Inc.
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Interior Arrangement

The accommodations are intended to provide comfortable cruising for two people on extended summer cruises, with a guest or two for shorter trips. In fine weather, there is plenty of room for lounging or additional sleeping on the aft deck.

In the forward cabin is a generous double berth within a private cabin. There are port and starb'd bureaus and lockers, plus a dressing area. A short ladder / stair leads up to the pilot house, and is attached to a sloped partition that forms the forward end of the engine box. Removing the ladder / engine box face exposes the engine for ease of maintenance and general access.

Within the pilot house there are two built-in seats on the port side, with a table between them. To starb'd is the wheel and a fold-down seat for the pilot. A chart desk is located aft of the pilot, and encloses a space that provides headroom for the head below.

The "dashboard" forward of the wheel will hold navigation instruments and engine controls. A magnetic compass will be mounted prominently forward of the wheel. A VHF radio will be mounted overhead near the helm. A flip-down step is located just inside the pilot house door, which doubles as a foot rest for the person at the helm.

The pilot house sole will be wood. Hatches on centerline will hinge up to provide complete access to the engine and machinery space below and will provide a water tight, air tight and sound proof closure to the engine compartment. Thorough sound insulation will be provided, as has been detailed elsewhere in this specification.

The engine space will be ventilated by fans, as detailed elsewhere in this specification. The "stack" will contain the engine room ventilation ducts and the exhaust stack, and will also provide headroom for the companionway leading aft and down to the galley and head. The aft companionway ladder will be mounted onto a removable sloped partition, and will provide complete access to the aft end of the engine and gear.

In the Aft Cabin a combination head / shower is located to starb'd. A fiberglass shower pan will be the sole for the entire compartment. The shower pan will extend a minimum of 6" up the sides of the compartment. A fold-down wooden seat will be located above the marine toilet for use as a shower seat. The head will have a vent fan and Dorade above.

On the port side, across from the head is the galley which will have plenty of counter space, a fixed diesel range /heater with oven, double stainless sink, and top loading refrigerator / ice box aft. The refrigerator will be cooled by a 12v DC cold plate system. The galley counter extends right around aft and below the aft deck, allowing a large flat work top with cupboards all around.

The water heater will be heated by engine cooling jacket water, and will be pressurized by a small self contained 12v DC pump/accumulator. The diesel range will also be set up to circulate heated water to the hot water tank. If desired, this combination will also be used to circulate hot water to a radiating unit in the forward cabin, having a small fan for air circulation.

To starb'd of the galley and aft is a single settee / quarter berth, partly extending below the aft deck. A small flip-down work table will be arranged for use while sitting on the quarter berth.

Aft on center is a ladder and companionway leading to the aft deck.

Interior Structure

Interior Structure is specified as follows:

Interior Joinery

Interior hardwood to be cherry or other medium colored hardwood. Dark woods such as teak or walnut and bright woods such as white oak will be avoided. Interior Joinery Surfaces are specified as follows, using finished dimensions in all cases:

Interior Finish

All joinery fasteners will be countersunk, bunged and sanded flush. There will be no exposed fasteners throughout the interior joinery. Formica surfaces are to be light grey or cream near-white. Interior panels which have not been surfaced with Formica (overhead; ceiling; bulkheads; shelving; locker interiors) are to be either oiled using Cetol, or varnished using a marine grade satin finish UV protected varnish. Sole areas, steps and ladders will treated so as to be non-skid.

Accommodation Space Ventilation

Additional ventilation will be provided to the living spaces by four "electronics" fans for low amp-draw accommodation space ventilation while at anchor. Approximate capacity will be around 15 to 20 CFM each. They will be individually controlled. One will be in the forward cabin, one will be in the pilot house, one will be in the head / shower, and one will be in the galley. There will be one 3" intake Dorade for each exit fan, located to suit.

Engine Space Ventilation

The drawings show the arrangement of the stack and the ventilation path for the Engine space intake and exit vents.

For an engine of less than 40 hp, ventilation for the engine space will be via exit air fans capable of delivering a total minimum of 300 CFM against an assumed static pressure of 0.5" of water. Two Jabsco heavy duty squirrel cage fans of 150 CFM each will be well suited to the task. Jabsco part #34739-0010. If it is anticipated that the vessel will be in the tropics, another Jabsco fan may be added to the array for a total of 450 CFM with all three fans operating. The advantage of this arrangement is to provide redundancy in the event of failure of one fan, and to allow them to be turned on only as needed, for example during cool-down after running the vessel. If the engine supplied is greater than 40 hp, the third fan will be required.

Minimum ventilation duct size will be 45 square inches of duct cross section on both the intake and the exit air sides, and after all deductions are taken for sound insulation or any other items which take up vent plenum space. This can be provided adequately by two round ducts of 5.35" finished inside diameter. Alternately, a square duct may be used of around 5" by 9" finished inside dimension. This duct size will accommodate three fans, and 450 CFM without creating excess resistance, and therefore excess noise.

Minimum louver area will be twice the duct area, or 90 square inches of louver area per side (intake side and exit side). The ventilation plenum will ideally be protected from water intrusion via Dorade style intakes and exits at the top. Per typical yachting etiquette, the exit air plenum will be to port, as will the engine exhaust. Intake will be to starboard. Sufficient air space will be provided around all exhaust components and their lagging to permit adequate cooling.

32' Tug Yacht TERRIER - Kasten Marine Design, Inc.
32' Terrier Under Way - Istanbul, Turkey

Power & Range

The engine space is located under the Pilot House sole and has access via sound proofed hatches above. Space around the engine will be adequate to get to all parts of the engine and gear.

The engine should heavy duty, low speed, and suited to the intended use. A slower turning, heavier engine will be a more dependable and more durable power source, however engine weight should not be greater than 700 lbs, complete with gear. The engine should not be overly tall or there will be an adverse effect on the headroom possible within the Pilot House.

The engine should be a marine diesel within the range of between 35 and 50 horsepower, using a continuous duty rating. For occasional light towing, for heavy weather travel, or for ice, the higher end of the power range may be preferred.

Using the Beebe algorithm and allowing for a 15% fuel reserve, a tank capacity of ±300 gallons total, range is approximately as follows:

Displacement hull speed is over 7.2 knots. It is preferred that the propeller revolutions be no greater than 750 RPM, therefore the reduction gear ratio will depend on the RPM range of the engine chosen.

Maximum propeller size is 24" diameter. The propeller will be of nickel-aluminum-bronze with three blades. Pitch and blade area will be determined by propeller supplier after the engine and gear have been selected.

Low levels of noise and vibration will be provided via adequate sound insulation and vibration damping. There will be flexible engine mounts and a flexible coupling on the shaft. Sound attenuation will be addressed elsewhere in this specification.

Shaft & Shaft Tube

A Vetus self-enclosed shaft assembly has been specified with a 2" shaft, assuming a 40 hp engine turning a 24" wheel at around 700 rpm. More horsepower or a deeper reduction gear will require a larger diameter shaft. Maximum bearing spacing with a 2" shaft is 8.5 feet.

Alternately, a standard shaft may be mounted in cutless bearings within an integrally fabricated shaft tube. In this case the shaft will be 2" in diameter Aquamet 22. Other alloys if used will meet the same strength and corrosion specification as Aquamet 22. With this shaft arrangement two cutless bearings will be provided having a 3" outside diameter. Bearing spacing is to be no greater than 8.5 feet. With this combination, the shaft tube will be a 3.5" Schedule 80 galvanized mild steel pipe.

Exhaust Line

Assuming 40 hp, the exhaust line will be 2" inside diameter, and will make use of a low back-pressure muffler. The exhaust line will have a flex coupling as close to the engine as possible, plus accommodation for expansion of the exhaust line. Materials will be chosen for maximum corrosion prevention in all exhaust line components.

A pyrometer will be provided in the exhaust elbow to insure against overloading of the engine.


All fuel and water tanks are to be integral with the hull. Each tank will have large cover plates to allow full access during building, for blasting and painting, and for future maintenance. Water tanks will additionally have smaller easily removed inspection and cleanout plates.

Fuel Bulk Tanks: Diesel fuel capacity will be 300 US Gallons total. Bulk fuel will be stored in three integral tanks below the side decks to port and outboard of the engine, outboard of the galley and outboard of the head. The two aft tanks will extend to the steel deck and will hold ±90 gallons each. The engine space port side bulk tank will extend to 4" above the DWL and will hold ±60 gallons. There will be a separate fill, vent and suction line for the three bulk fuel tanks. Fuel suction lines will emerge from the lowest point on each fuel tank.

Fuel Clean Tank: The fourth fuel tank will act as the clean day tank only. The clean diesel day tank will extend to 4" above the DWL and will hold ± 60 US gallons. The "clean tank" will not be able to be filled from on deck. There will be a diesel fuel manifold arranged to allow "polished" fuel only into the clean day tank. The clean day tank will have a fill (from the manifold only) a suction, a return (from the engine), and a vent separate from the other tanks. Fuel will be transferred by electric pump and by manual backup pump.

Water Tank: Water tank capacity is 120 US Gallons. The water tank is to be integral with the hull and is located in the forward cabin below the V-berth. The water tank will be able to be filled from on deck, and will have a fill, suction, vent and a clean-out plate. If fresh water flushing for the marine head is planned, then it will be most suitable to provide a separate polyethylene "flush water" tank to prevent any cross contamination to the drinking water supply.

Black Water Tank: The holding tank will be a maximum of 35 gallons. The holding tank will be heavy wall polyethylene, built to fit.

Grey Water Tank: The galley sink / head basin / shower sump tank will be a maximum of 15 gallons, and will be built with heavy wall polyethylene.

All polyethylene tanks will have removable lids for occasional access / maintenance. Poly tanks will have a minimum wall thickness of 3/8" up to 35 gallons, and will have a minimum wall thickness of 1/2" up to 70 gallons. Poly tanks will have baffles located no farther apart than 18" in any direction.

12 Volt DC Electrical

The electrical system will be 12 volts DC. There will be 2 storage batteries having a 4-D form factor. The batteries will be wired as a single 'house' bank. Although the engine will have its own start battery, the 'house' battery bank will also be made available for starting.

The specifics of the charging system will be according to the supplier of the charging equipment.

The DC system will be a "floating ground" type of system fully isolated from the hull and all the hull fittings. The engine will be electrically isolated from the hull via flexible mounts and flexible coupling.

There will be no bonding system attached to the 12v DC system.

Refrigeration will be 12v DC, or will be belt driven, per owner preference. Receptacles will be provided for small 12v DC loads, such as a laptop computer, shaver, cell phone and so-forth: One in the head; one in the galley; one in the quarter berth aft; two in the pilot house; two in the forward sleeping area. Where there are two of them in a compartment, the 12v DC receptacles will be arranged one on each side. Additional locations may be specified by the owner as required.

AC Electrical

The boat will be provided with a very simple AC wiring system for occasional power tool convenience, for charging the batteries and for operating the refrigeration while dockside. Means will be provided for bringing aboard AC power through an approved shore power cord, entering the vessel via an electrically isolated marine rated AC shore power receptacle in the side of the Pilot House.

There will be an Isolation Transformer provided, complying with the most recent ABYC regulations. There will be no interface between the AC power and the 12v DC system. The green grounding wire will be connected (or not) according to the instructions accompanying the isolation transformer, per ABYC regulations.

A conveniently located two pole switch will be provided in order to easily disconnect and completely isolate the batteries (both positive and negative legs) from all of the vessel's DC electrics while being charged via shore power. Bilge pumps may be directly wired to the batteries, and if so they will be provided with in-line fuses.

There will be a small AC panel for distribution. The AC panel will be located on the inboard face of the pilot house seating or on the galley / pilot house common bulkhead, facing aft into the galley.

Corrosion Protection System

There will be no active corrosion protection system provided on this vessel. There will be no bonding system provided on this vessel. A passive corrosion monitor may be provided if desired.

All dissimilar metal fittings will be completely and thoroughly isolated from the hull via a combination of paint, micarta (phenolic resin laminate) wafers, liners, and adhesive caulking. Each separate underwater fitting, where practical, will be supplied with its own separate zinc anode or anodes. The hull will be provided with zinc anodes as follows:

The anodes will be approximately 4.5" diameter standard "rudder cheek" zincs (flat, round, lens shaped) having one bolting hole in the center. Type 316 stainless studs will be provided for attachment of these anodes. Studs will be 1/2" national coarse by 2" long, or a metric equivalent.

Through Hull Fittings

All discharges will be to port, all intakes will be to starboard.

Through hull valves located above the waterline may be attached to Schedule 80 galvanized steel, or Type 316-L stainless pipe nipples welded to the hull above the load waterline. Through hull valves located above the load WL will be RC Marine "Marlon" Nylon fiberglass reinforced plastic valves.

Through hull valves located below the waterline will be flanged bronze tapered valves mounted onto bronze through hull fittings, and will be isolated thoroughly from the hull surfaces. Alternately, under water through hull valves may be flanged, and mounted to integrally welded flanges per the Building Plan drawings. Metal through hull fittings such as transducers will be located as necessary and will be thoroughly isolated from the hull.

There will be no electrical continuity between the through hull fittings and the hull. All dissimilar metal fittings will be thoroughly isolated from the hull surfaces using the vessel's intact paint system, isolation sleeves, Micarta wafers and marine grade caulking, in combination.

Ground Tackle

There will be one primary bow anchor: a Bruce 44 lb (#22) or CQR 45 lb anchor. There will be an anchor rode roller sheave on the centerline forward. Primary anchor rode will be 250 feet of 5/8" Braided Nylon line and 60' of 5/16" HT galvanized chain. Spare anchor rode will be 30 feet of 5/16" HT galvanized chain and 150 feet of 5/8" Braided Nylon line. Stern anchor, if fitted, will be a 22 lb Danforth. Stern anchor rode will be 15 feet of 5/16" HT galvanized chain and 150 feet of 5/8" Braided Nylon line. There will be 250 feet of 5/8" Braided Nylon line made into mooring lines.

A manual vertical capstan style anchor windlass will be provided on the foredeck.

There will be four stainless "horned" hawse holes welded into the bulwark, two per side. There will be one stainless hawse hole on center aft, and two on either side of the windlass forward. There will be one heavy duty bitt welded onto the after deck. There will be two mooring bitts forward, one on either side of the fore deck.

There will be three large fenders of the spherical fisherman type.

The Rudder

The rudder profile, the rudder stock size, and the bearing arrangement are shown on the Construction Drawings. The rudder is drawn to show two optional configurations:

  1. First, a standard rudder having its turning axis at the leading edge is illustrated for the sake of simplicity of construction.
  2. Second, a foil shaped, balanced rudder having its turning axis located farther aft is optional, and will provide easier steering.

End Plates: An end-plate is located at the bottom of the rudder, also increasing rudder effectiveness. The hull provides an effective "end-plate" at the top of the rudder, so there is no end plate at the top. Using an end plate on the bottom of the rudder, the rudder angle required for course changes will be much less, since the prop-wash is better contained. This eases the work load imposed on the autopilot.

Counterbalance: Using some amount of counterbalance on the rudder, the effort required to turn the vessel will also be considerably less. This is a benefit both to the autopilot and the steering gear. The general rules for creating a balanced rudder are as follows:

If there is no end-plate at the bottom, the turning axis may be moved aft a maximum of 8% of the rudder cord length. With an end plate at the bottom, the rudder stock axis may be moved a maximum of 15% of the cord length aft. If a balanced rudder configuration is preferred, the axis of rotation of the rudder stock will be moved aft (leaving the rudder in the same place) to provide a counterbalance for easier steering. In order to make this possible, the rudder support shoe will have to be lengthened.

Foil Shape: A NACA foil shape will provide greater lift in order to maximize steering effectiveness, as well as low drag. The foil shape is from the NACA 0015 foil family. This shape provides the most lift with the least drag and will therefore steer well, will have large range of steering angle without stalling, and will have much less drag than a flat plate or flat sided rudder.

To reduce flutter and increase steering effectiveness, there will be a "flat" at the trailing edge of the rudder, maintaining the same thickness of the foil during the last 10% of the foil's cord length.

The rudder is shown on several of the drawings without any counterbalance, primarily for simplicity of construction. If it is deemed necessary or desirable in the future, wedges may be added to the trailing edges of the flat plate rudder using stainless studs (type 316-L).

Rudder Construction Notes

There will be a 2.5" hole in the rudder, located at the axis of rotation, and in line with the centerline of the propeller shaft to permit withdrawing the shaft without dismounting the rudder.

The rudder shaft will be 1.8125" diameter cold rolled steel or type 316-L stainless round rod, welded integrally into the rudder foil. It will be carried in a galvanized rudder tube of 2" Schedule 80 galvanized pipe. The resulting clearance is correct for using boat trailer wheel bearing grease as lubricant.

The advantage of this method is simplicity, ruggedness, long life. With boat trailer wheel bearing grease, there is no need to use a stuffing box at the top of the rudder tube, and there is no need to provide for dismounting of the rudder.

The rudder heel bearing will be built as illustrated in the construction drawings. There will be a nylon or UHMW thrust bearing wafer below the rudder shaft in the heel fitting. The heel bearing will consist of heavy wall pipe or mechanical tubing, and will be tapped for two type 316 stainless zerk fittings (available from out-drive suppliers).

Boat trailer wheel bearing grease will be used both in the rudder heel fitting and in the rudder bearing within the hull. The rudder bearing tube will be greased via zerk fittings accessed from within the lazarette.

Using this rudder bearing arrangement, it will not be necessary to provide a removable rudder heel fitting. In the unlikely event the rudder ever needs to be removed, the heel fitting can simply be cut off, and re-welded afterward.

Lofting Notes

Offsets: The offsets are given in decimal inches. Metric offsets can also be provided as needed.

Deck & House Cambers: Offsets for the house & cabin are given. The cambers are not constant throughout. The individual camber curves can be faired from the Lines Drawing by first taking heights at the centerline, and at each buttock line. From those, separate faired camber curves can be struck through the butts for a few key stations.

Fantail & Bulwarks Aft: The angle of intersection of the fantail stern with the aft bulwark has required that a "flat" to be drawn in at a constant 2.375" height. This dimension is simply the outside diameter of the 2" pipe used for the rub-rail. This method is required in order that the deck-edge pipe will show a constant semicircle outboard, rather than being "pinched off" by the diminishing angle, and rather than being placed in plane with the face of the heavily raked topsides around the fantail aft.

Frame Spacing: Spacing for the frames as shown on the Construction Drawings is not the same as the station spacing given on the Lines Drawing. The frames are instead placed to take maximum advantage of the given interior layout, to match the bulkhead placement. The frame shapes will be easily found once the long lines have been placed on the loft floor. With the long lines lofted, the actual frame locations can be drawn on the profile and the plan view, then the offsets picked up for the body view to give the frame shapes.

Long'l cutouts in the frames should be laid out on the lofting floor and should be located as drawn.

Hull Construction Notes

The hull shape has been designed so that the plating can be easily applied. All hull surfaces are developable. Minor pre-forming may be required around the stern fantail and around the Pilot House forward end. The rudder foil leading edge will require pre-forming for accuracy.

The hull plating should be permitted to have its natural amount of "belly" and the framing should be cut to fit the anticipated "belly" amount according to the shape given on the lines drawing. Per the requirements of the ABS Rule, all transverse and longitudinal framing will be shaped so as to fit fully in contact with the hull skin, and welded according to the enclosed Welding Specification (attached).

Longitudinals will penetrate and will be fully welded to all transverse framing members. Longitudinal framing members are to terminate on transverse framing members, and shall not terminate on the hull plating.

The topside long's continue aft to just past the first "Cant" Frame in order to span the plating butt located there. All plating butts are most easily kept fair if "sister" longitudinals are provided across the butts, as shown. It is very much to the builder's advantage to keep plating butt welding to a minimum. The ideal butt locations have been illustrated on the Construction Drawing.

Transverse frames and longitudinal stringers are mild steel flat bar throughout, spaced as given. Maximum permitted long'l spacing is 10" on the bottom, and 12" elsewhere. The longs are parallel to centerline on deck. On the bottom and sides, the long'ls converge as fair curves. Where long's are closer than half the specified spacing, they may terminate on the nearest frame so that no region of plating has a long'l spacing greater than specified.

Terrier Scantlings

Hull materials to be A-36 Mild Steel. Alternately Corten steel may be used, a variety of High Strength Low Alloy (HSLA) steel.

Steel Hull Plate

Steel Hull Framing



Weld Size & Spacing

Dimensions in Decimal Inches. Spacing given is Center to Center.

Intermittent Staggered Fillets

Weld Length


Weld Face Width

Fwd 1/4 of Bottom Frames to Shell




Engine Space Frames to Shell




All Other Frames to Shell




Beams; Long's; Girders to Shell




Tank Stiffs to Tank Shell




Double Continuous Fillet Welds

Frame; Long'l; Girder ENDS



Girders to Intermediate Floors



Engine Foundations to Shell



Framing Above Prop to Shell



Tank & WT Bhd Plating to Shell



Deck Plating at Edge



Wood Construction Notes

The Cabin Top, the Pilot House Top, and the Foredeck are made up of 5 layers of 1/4" marine grade hardwood plywood, laminated in place to fit the local camber using epoxy resin. Additional framing is not needed. When the house tops have been finished and trimmed to size they will be covered with a layer of 6 oz. fiberglass cloth bedded in epoxy resin, then filled with thickened epoxy resin, and then painted with the epoxy paint system used by the steel structure elsewhere on the boat.

These regions may NOT be built of steel due to excessive weight.

Aft cabin top and foredeck are to be bolted directly onto the painted steel faying surfaces as detailed on the plans, and will be bedded in adhesive caulking such as Sikaflex or 3M-5200. All bolt holes in the steel faying surfaces will be pre-drilled oversize and painted using the same protective paint system as for the hull.

Wood Structural Scantlings

Windows & Ports

All windows will be glazed with tempered and / or laminated safety glass. All portlights will be of the opening type, and will have galvanized steel, aluminum, or stainless steel frames.

The forward pilot house windows will have a minimum of 3/8" glass (ABS specification). The pilot house side windows (including the PH Door) will have a minimum of 5/16" glass (ABS specification).

Pilot house windows will be mounted into the pilot house mullions and window frames using adhesive glazing caulking and window-stop battens. Fastenings will not penetrate any window glazing.

Paint System

Prior to delivery, all steel materials will be thoroughly pre-blasted to a commercial near-white blast and primed with Devoe 302 or equal weldable epoxy primer. After all steel fabrication is completed, the steel structure will be sand blasted and coated with an epoxy paint system, briefly summarized as follows.

With the exception of the anti-fouling paint, the protective coating system is specified as being Ameron's Devoe System. Nearly any other epoxy paint system may be used, provided that surface preparation and Dry Film Thickness (DFT) mil thicknesses are at least as specified. The eventual DFT mil thickness will very approximately equal the Wet Film Thickness (WFT) times the percentage of solids in the paint being applied. For example, a 60% solids epoxy paint applied at 10 mil WFT will dry to approximately 6 mils DFT.

One mil = 0.001 inch, or 0.0254 millimeter.

All sand blasting will be done according to temperature and relative humidity recommendations of the paint system being used. Primers will be applied each day to cover that day's sandblasting, and prior to any significant temperature drop or rise in relative humidity at the end of the day.

Steel Hull Interior: After fabrication, if all steel has been supplied "blasted and pre-primed" the interior of the steel hull and decks will be sandblasted to a "commercial brush blast" standard in order to clean all welding and cutting areas. If the steel has not been "blasted and pre-primed" prior to delivery, all metal surfaces will be sandblasted to a "commercial near-white blast" standard prior to being painted.

The interior steel surfaces will be primed with Devoe 201 primer or Devoe 236 epoxy. All interior steel surfaces will then receive a minimum of three coats of Devoe 236 high build epoxy paint.

Where blown in polyurethane insulation will be applied, the paint system will have a minimum thickness of 12 Mils DFT. Where cut-sheet foam insulation is to be applied, the system will have a minimum thickness of 16 Mils DFT. On any surfaces exposed to view (areas which will remain uninsulated and without ceiling such as the forepeak, the lazarette, and bilge areas below the first long'l) the paint system will have a minimum thickness of 16 Mils DFT, plus two layers of Devoe 229 acrylic epoxy color coating applied over the high build coatings.

Tanks: After thorough blasting to remove all traces of contamination, and to remove all traces of any zinc based or other construction primers, all integral water tanks and fuel tanks will be coated with a minimum of three coats of Devoe 236, using colors approved for potable water. Minimum coating thickness will be 16 mils DFT.

Steel Hull Exterior: After fabrication, if all steel has been supplied "blasted and pre-primed" the exterior of the steel hull and decks will be sandblasted to a "commercial brush blast" standard in order to clean all welding and cutting areas. If the steel has not been "blasted and pre-primed" prior to delivery, all metal surfaces will be sandblasted to a "commercial near-white blast" prior to being painted.

Below the waterline, all traces of Devoe 302 primer will be removed. All blasted areas will be primed with Devoe 201 or Devoe 236. All exterior surfaces will then receive a minimum of three coats of Devoe 236 high build epoxy paint. The exterior paint system will have a minimum thickness of 16 Mils DFT prior to application of the color coatings or antifouling paints.

All exterior hull and deck areas above the boot stripe will receive a minimum of two layers of Devoe 229 acrylic epoxy color coating applied over the high build coatings. Non-skid will be placed on all deck surfaces. Devoe 229 Acrylic Epoxy coatings have been chosen for their extreme ruggedness, ease of application, ease of re-coating, and for compatibility with the Devoe epoxy barrier coating system. Consideration may also be given to use of Devoe 239 LP color coatings in place of Devoe 229.

Bottom Paint: Three coats of Woolsey Neptune (the solvent based type) or Pettit Trinidad bottom paint will be applied to all under water areas, and brought up to the top of the boot stripe line.

32' Tug Yacht TERRIER - Kasten Marine Design, Inc.
Terrier on the Bosphorus, Istanbul, Turkey

Thermal Insulation

Insulation throughout will be either blown in polyurethane foam, or will be cut-sheet foam (to be decided by owner and builder).

If cut sheet foam insulation is chosen, Ensolite or Neoprene foam will be the preferred choice, being flexible, closed cell, mildew resistant, and fire retardant. Cut-sheet foam will be preferred for the steel cabin trunks. The pilot house upper portion will be of wooden construction, and may receive Ensolite cut-sheet foam as well if desired.

If blown-in polyurethane insulation is used on the hull, a fire retardant formulation will be chosen. Insulation will be applied to the deck and the hull sides down to the level of the first longitudinal. There will be no thermal insulation in the lazarette, in the forepeak or in the bilge below the level of the first longitudinal. There will be a fire retardant sealant type of paint coating applied to cover all blown in foam insulation.

Thermal insulation shall provide an R value of at least 6 when in a new state (equivalent to 1.5" of sprayed, two pound per cubic foot density polyurethane foam).

Engine Room Sound Attenuation

Sound attenuation will be given a top priority. There will be no thermal insulation in the engine space. Instead, sound deadening materials will be used against the painted hull surfaces. Sound attenuation will be addressed on four fronts:

Structure Borne Sound Isolation: Soft Mounts, Flexible Coupling, Flexible Stuffing Box will be required for the main engine. Auxiliary mechanical equipment to also have flexible isolation type of mounts to prevent structure borne noise. Equipment requiring structure borne noise attenuation via isolation mounts includes: Main Engine; Drive Line; Watermaker Pump; Refrigeration Unit; Ventilation Fans; Water Pressure Pump.

Structure Borne Noise Absorption / Dampening: Areas such as Engine Girders; Hull Surfaces adjacent to the Engine Girders and directly above the Propeller will have weighted sound absorption / dampening materials applied. Materials will be specified from readily available sound attenuation products.

Air Borne Noise Isolation: All avenues for air borne noise between Engine Room and Accommodation Spaces will be sealed tight, including mechanical and electrical chase ways after installation of plumbing, cables, and wiring.

Air Borne Noise Absorption: All surfaces between engine room and living quarters shall be insulated with sound absorbing foam on the Engine Room side. Sound barrier foam to consist of 2" total, including White or Silver Mylar surface coating, foam absorption layer, weighted vinyl damping layer, and foam de-coupling layer. Installation to be done in such a way that the insulation is mechanically captured. All edges and joints to be sealed with Silver or White Mylar surfaced tape. All engine room air ventilation ducting will be treated with the same materials to a thickness of 1" total.

Engine Room Fire Control

A Fireboy or similar brand of fire control system will be installed in the engine room. Automatic engine shut down will be connected to main engine. A manual trigger is to be fitted on the PH dashboard.

Trimming Ballast

Ballast is not required for the stability of this vessel, only for trimming. There is an allowance for approximately 1,000 lbs of lead as trimming ballast, to be placed below the sole in the forward stateroom as needed. The exact amount of ballast is to be determined after launch, with the vessel complete, and all tanks loaded halfway, ballast being added or moved until neutral trim is achieved. If less trimming ballast is required, there is no need to use the full allowance.

Equipment Summary

This list of equipment is a summary of the main components only.

The Building Plans

The Building Plans consist of the following:



Correct displacement, trim and balance are assured by following the plans. In order to assure that the vessel will trim correctly and behave as intended, larger components need to be placed as specified. Items not directly addressed in this Specification or detailed within the Building Plans will be specified and built according to owner choice, and will be according to good boat building practice.

The builder will provide shop drawings as needed for joinery, hatches and other items. The builder will also provide basic system schematics and layout sketches for electrical, fresh water, salt water, engine cooling, fuel piping for owner review and approval.

NC Cutting Option

The hull and superstructure have been computer modeled and faired, providing an excellent opportunity for the structure to be further detailed for NC cutting. If the hull will be professionally built, a substantial savings can be realized via computer cutting. Feedback from commercial builders indicates that from 35% to 55% of the hull fabricating time can be saved by using NC cutting, and the accuracy is vastly greater than with manual lofting and cutting. Amateur builders can save a much larger percentage of their time, possibly on the order of 50% to 70% depending on their experience level.

More information about this option and its benefits can be found within our NC Cutting and Design Stream web pages.

The basic Building Plans provided by Kasten Marine Design, Inc. are intended to illustrate the general type of construction to be followed. The basic design, arrangement, strength and weight shall be in accordance with such plans.

Details and dimensions shown on the plans shall be followed insofar as practicable, however it will be the responsibility of the Builder to check such dimensions and details as needed to satisfy himself, by full size layout if necessary, so that interferences are eliminated and that matching or fitting parts are properly installed.

The Builder will notify the Owner and Kasten Marine Design, Inc. for mutual resolution of any dimensions and details that he cannot follow or that he recommends changing. It will be the responsibility of the Builder and of his subcontractors and equipment suppliers to assure that all mechanical components are suited to the purpose for which they are intended.

System Schematics

The following notes are intended to clarify the design and development of system schematics.

In general, the Builder will be the best qualified to provide the schematics for, the engineering of, and the installation of the Basic Systems and of the Integrated Systems as listed below, in accordance with the general guidelines provided within this Vessel Specification, with current ABYC recommendations, with good boat building practice, per the owner's specific requirements, and subject to the owner's approval.

Basic Systems

Per owner or builder preference, in addition to the Basic Building Plans, Design Documents and NC Cutting Plots listed above, if requested, Kasten Marine Design, Inc. will be available during or before the vessel's construction, on an hourly basis, to design or to review Basic System schematics for the following:

Integrated Systems

Aside from the Basic System Schematics listed above, the other various Integrated Systems and their schematics are complex and specialized to the point that the builder or installer or supplier of the equipment will be required to engineer those systems according to their own expertise, following the general guidelines expressed within this Vessel Specification as closely as possible.

Systems will conform to ABYC norms, unless specifically otherwise stated in these specifications. Systems will also be in compliance with European Union Recreational Craft Directive (EU RCD) Class One (Ocean) requirements for structure and equipment where practical, feasible and economical.

Specifically, these Integrated Systems include but are not limited to the following:

In general, only the suppliers / installers of these various complex and highly specialized Integrated Systems will be considered to be qualified to design and review their schematics, or to determine whether the systems comply with the general guidelines within this Vessel Specification. Therefore, Kasten Marine Design, Inc. does not propose to review the Integrated Systems nor their schematics, nor to offer specific comment on them, except to address questions from the suppliers / installers for best compliance with the general intent of this Vessel Specification.

If it is desired to have a third party review of the systems as they are installed, the owner will make use of an independent surveyor for that task, hired by and paid for by the owner.

General Terms

CHANGES: Correct displacement, trim, stability and hull strength are a tightly integrated whole. Arbitrary changes made may adversely affect the vessel's trim, and therefore the vessel's behavior, performance, and safety. In order to assure success with the building of this vessel, it is assumed that the plans and specifications will be followed as closely as possible.

There will be no changes from this specification or to the vessel's structure, materials, equipment, or layout without explicit written approval from Kasten Marine Design, Inc.

References to trade names and catalog numbers are intended to be specific. Where substitutions are necessary, the owner and / or Kasten Marine Design, Inc. will approve them on the basis that there be no sacrifice in quality or ease of maintenance. Changes from items listed by brand and model will be made only on written approval by Kasten Marine Design.

Changes made without written approval from Kasten Marine Design, Inc. will relieve Michael Kasten, and Kasten Marine Design, Inc. of responsibility for any possible effects of those changes.

WORKMANSHIP: The Builder will construct and equip this vessel complete in every respect and ready for service. Omission from the plans and / or this specification of any items which according to generally accepted practice are necessary for the proper operation of the vessel will not release the Builder from supplying and installing same.

Materials and manufactured articles of construction and equipment are to be of the best quality for their respective purposes. The Builder will assure that the materials, workmanship, construction, machinery and safety equipment of this vessel will be according to generally accepted good boat building practice, and that the vessel will be suitable for registry as a pleasure vessel.

It is recommended that the Builder follow the standards and recommended practices of the American Boat and Yacht Council, the US Coast Guard or other local authority as applicable to a vessel of this type.

WARRANTY: The Builder will warrant the vessel and its equipment are fit for going to sea, and will timely repair or replace workmanship and materials found defective within one year of vessel delivery. Builder will ensure material supplied by others is also warranted for one year from vessel delivery, and will assist in ensuring any needed repairs or replacements to such material are accomplished in a timely manner.

DESIGN OWNERSHIP & USE: Kasten Marine Design, Inc. owns the exclusive rights to this vessel design, including the design concept, the interior and the exterior layout, the vessel's appearance, and any other details, drawings or documents developed by Kasten Marine Design, Inc.

The Builder may not copy this design, its concept, layout, appearance, drawings, documents or other details for future use on any other vessel.

This vessel design, the Study Plan drawings; the Building Plans; final Construction Drawings; NC Cut Files; this Specification and all other documents listed above, including any drawings and specifications that may be additionally prepared by Kasten Marine Design, Inc. for the purpose of building this vessel are and will remain the copyrighted property of Kasten Marine Design, Inc.

On completion of the Building Plans as outlined above, permission is granted to the owner and the builder of this vessel to make any necessary in-house copies of these documents as needed during the construction and the subsequent use of this vessel.
Upon supply of the completed Building Plans to the Builder, a limited license is granted to the builder and owner to build one single vessel from these plans and documents. No other use is permitted.

Permission to use these documents for any other purpose; to build other vessels from them; to reproduce them for distribution to others; to publish them in print or on the web; etc. may be granted only by Kasten Marine Design, Inc. in writing on a case-by-case basis, at which time a royalty will be due and payable to Kasten Marine Design, Inc. by the builder and /or owner of that vessel. If subsequent vessels built to this design are of interest, please inquire.

ADVERTISING: Kasten Marine Design, Inc. retains the right to publish details of the construction or drawings or specifications of this vessel, or to promote this vessel or its builder by whatever means deemed appropriate, including magazine articles, advertisements, web pages, or any other means.

If at any time this vessel is advertised for charters or for sale, or if articles about this vessel, its construction or its travels are published, the Owner and Builder agree to feature Michael Kasten and Kasten Marine Design, Inc. as the vessel's designer, and agree to also include the URL: and in any published ads or articles or web pages in which this vessel is involved.

BUILDER CONTRACT: This Vessel Specification, along with these General Terms, the above listed Building Plans, the Equipment List, the Welding Specification, and the Vessel Painting and Insulating Specification will be made part of the construction contract or agreement between owner and builder.

Copyright 1995 - 2011 Kasten Marine Design, Inc.
All Rights Reserved

32' Tug Yacht TERRIER - Kasten Marine Design, Inc.
Terrier - Istanbul, Turkey