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The 45' Widebody Motor Yacht


45' Widebody Mootor Yacht - Kasten Marine Design, Inc.
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Perspective Above Aft | Perspective Far Aft  | Perspective Side | Perspective Above Side | Perspective Forward

Copyright 2016 Michael Kasten


The request for this design was to create a trawler yacht suited for a couple to live aboard with occasional guests.  A vessel suited to ocean travel, and for an active pursuit of life on the water.  Low build cost, a simple layout, and low maintenance were priorities. Propulsion via a four cylinder turbo diesel assures modest machinery weight and good fuel economy.

The lines of the vessel reveal an easily driven hull, with an interior layout similar to the 40' Widebody Coaster.  The "Widebody" main cabin provides plenty of interior space for two as a live-aboard with another couple as guests, and entertainment space for six.  The transom is designed for optimum access to the water and to the shore boat.

Particulars are:

Stability will be excellent due to the raised fore-deck and the widebody house structure, both of which provide considerable reserve buoyancy and therefore greatly increased large angle stability. As such, the 45' Nomad will easily meet the EU RCD "all ocean" category.


Hull; deck; cabin and pilot house construction are planned for aluminum construction. Scantlings will be according to the ABS Yachts Rule - 2015, and will also comply with ISO rules used within the EU.  It is anticipated that plating and framing will be detailed for NC cutting. For more information about our use of CAD for NC cutting, please see our Design Stream article.  


The engine specified is a John Deere 4045 TFM - 4 cylinder turbo diesel that produces 120 hp at 2,400 rpm (M-2 Rating). It will be mated to a Twin Disc gear using a 3.5:1 reduction to drive a three blade propeller.  An alternate stern gear arrangement would be to use a Sabb HVP-65E gear at 3.8 : 1 reduction and a Helseth or Nogva Controllable Pitch Gear.  Theoretical hull speed is 8.7 knots.  Due to the relatively light Displacement to Length ratio, the John Deere 4045-TFM should be able to provide a top speed of around 9.5 knots, depending on load. 

The optimum cruising speed for long range voyaging is 7.0 to 7.5 knots.  Assuming a tank capacity of 800 US gallons and a 12% reserve, according to the Beebe algorithm the range at 7.0 knots should be around 3,500 NM.

Adequate space has been provided in the engine room for a small generator, plus all the ancillary machinery that is usually expected such as water maker, filters, pumps, fire extinguishers, muffler, electrical panels and so forth - plus the bulk fuel tanks...!

Aft of the engine room is a large storage area below the saloon and galley. Items slated for this area are dive equipment, tools, spares, and stores for long range voyaging. Below the aft deck is the lazarette, plenty large enough for all the myriad lines, fenders, fishing gear and the usual "stuff" that accumulates onboard...  


The aft deck, saloon, galley and pilot house are all at one level.  In the cockpit area aft, a ladder will lead up to the "boat deck" and Flying Bridge via a hinged hatch.   An additional means to access the boat deck and flying bridge may be located just aft of the pilot house side decks.  On the house top, it is possible to arrange a low profile, lightweight Flying Bridge with seating for four to six.

The exterior side decks outboard of the pilot house are at the same height as the pilot house sole.  The foredeck spans the full width of the vessel forward of the saloon / galley, extending from the bow, aft to the pilot house side decks.

Exterior watertight doors are located on each side of the pilot house, and on center at the aft end of the saloon. The aft deck is surrounded by substantial bulwarks to each side, and there is a center bulwark right aft. To each side of the center bulwark steps lead down to the swim platform right aft. The aft swim deck will have a removable dive ladder, as well as a receptacle for a hinged passerelle plank for ease of boarding when moored side-to or stern-to.

There will be an A-frame mast and a pair of A-frame paravane poles.  A boom will be provided to allow easy placement of a shore boat on the house top above the saloon. 


I have arranged the stations at regular 28 inch intervals. That is a favorable module for the interior arrangement, since conveniently four frame bays make a perfect size for a sleeping cabin (9’ – 4”) with room at the end of the master berth for a dressing area.  Three frame bays (7’ – 0”) make a generously sized guest cabin / office.  Generally two frames (4’ – 8”) make a very adequate head compartment or galley, and one frame bay (2’ – 4”) is perfect for a closet or apartment sized washer / dryer, etc.  This kind of modular layout is very much the norm for our metal boat designs.


With that in mind, I made the forward cabin four frame bays (9’ – 4”) in length in order to achieve a walkaround 'island' berth forward on center, flanked by shelves, with ample room for a pair of large wardrobe cabinets outboard with a dressing area on center. An arrangement of that kind can be seen on the Far Horizon 54 in both the forward and aft cabins.

I then dedicated three frame bays (7’ – 0”) to the guest cabin / office (to starb’d) and head compartment (to port).  Seven feet of length provide for a head compartment that contains a WC, sink, and a separate shower compartment. The guest cabin will have a bureau forward and aft of the entry, and a double berth outboard.  The double berth is to be arranged as a "berth in a box" so that when not needed as a berth for guests, the lid can be closed to allow use as a large office desk / project table.  

Aft of that on the lower level, four frame bays (9’ – 4”) are given to the engine room. Beam in that location is 15’ – 6” so with roughly 2’ – 0” on each side used for bulk fuel tanks the ER interior is just over 11’ wide inboard of the tanks. With a 24” wide engine, that leaves some 4’ – 6” outboard of the engine on each side. With a 24” wide wrap-around seat facing toward the engine, that leaves a reach of 30” to the engine. That allows ample space to pass through and around the engine by scooting around on the seat, with full seated headroom throughout. We have used this arrangement successfully quite often.

One of the stated requirements was to have a place to stand with full headroom in the Engine Room.  This, as it turns out, is not at all an easy task, but we will accomplish this by dedicating one full frame bay with standing headroom at the forward end of the E.R.  This tucks conveniently below the Pilot House dashboard.  Nice..!

On the lower level just aft of the engine room is a large storage room occupying three frame bays (7’ – 0”) in length by the full width of the vessel. Aft of that below the aft deck is the Lazarette, which occupies two frame bays in length (4' – 8").  Aft of the Lazarette are a pair of lockers outboard above the swim deck that can be used for gas / propane so that those compartments can be vented overboard, and then on center below the swim platform is another storage compartment for lines / fenders / stuff... 


This being a Widebody layout, there are no walkways down the side outboard of the aft house, nor any need for them, since it is quick and easy to access the aft deck via the saloon.  So starting from aft, first there is the swim deck.  Stepping up from there, we find ourselves on the aft cockpit deck.  Since there is no need to go forward from from the aft deck outboard on either side, an “L” shaped seat can be placed outboard and forward on the aft face of the house on both sides.  The inner transom provides an ideal spot for a counter top with BBQ and Sink Alternately, a bench seat located aft against the transom would be nice. 

Inside on the main deck, six frame bays (14’ – 0”) are dedicated to the saloon / galley / pilot house, plus another two frame bays for a large dashboard (4' – 8").  In all, the main deck house encloses a length of  18' – 8"...!  The pilot house sides are inset approximately 24 inches, which at sole level (not including the dashboard) extends for two frame bays (4' – 8").  The PH inset creates a pair of side decks, one on each side, located at PH sole level.   This arrangement leaves four frame bays for the saloon and galley (7' – 0").  Since the ‘widebody’ extends all the way outboard on both sides in way of the saloon / galley, the interior of this space is approximately 14’ wide.  

There are several possible ways to use this space.  At the forward end there is the pilot house which has its functionality focused on navigating and piloting.  At anchor, its focus shifts to that of being a good 'perch' from which to watch the activities in the anchorage.  With this in mind, it is easy to imagine a pair of piloting chairs that swivel around to face aft so they can be used as part of the social activities in the saloon / galley. 

The galley always turns out to be the center of attention socially, therefore having it integrated with the saloon seems ultimately sensible. In this location, galley activities need not disturb the helm, for example when running at night.  Since the portion of the deck house that's located aft of the pilot house is twice as wide as it is long, probably the best arrangement for the saloon / galley will be similar to that used on the Swallow's Nest 60.   This places the galley outboard along one side, with a peninsula extending inboard at both forward and aft ends – i.e. a large "U" shaped galley with a panoramic view and plenty of workspace for two or more.

Opposite the galley is the ideal spot for a large dinette.  If the dinette were raised up a bit, those seated would be at eye level with anyone standing, and would be afforded the same view.  If the pilot's chairs were a movable type, they could then be moved to the table which would then comfortably seat six, or up to eight in a pinch.  In the Swallow's Nest 60, it was preferred that the pilot chairs be fixed, but that they swivel around to access a pair of short counters.

At the forward end of the pilot house a companionway will access a stairway to below.

With this arrangement, the pilot house is 'included' in the saloon.  As well, since the aft deck can easily be enclosed with a canvas / vinyl dodger, the aft deck can easily participate as part of the main deck living space.


The layout described here fits nicely into an overall length of 45 feet.  In all, the 45' Nomad Widebody Trawler Yacht will be economical to build, simple to maintain, and a pleasure to travel with... 

For other similar designs in this series, please see the following:


45' Widebody Trawler Yacht NOMAD - Kasten Marine Design, Inc.
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