Messing about in boats since 1975.  Online Since 1997.

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The 43' Pilot Cutter

"RAVEN"

43' Cutter - Raven - Kasten Marine Design, Inc.
Starb'd Aft Perspective | Starb'd Forward Perspective | Port Aft Perspective

General Concept

Raven was originally drawn for a fellow who stands nearly 7 feet tall...! Thus, Raven has a fairly deep hull very much in the Pilot Cutter / Channel Cutter tradition. Raven also has a fantail stern - typical as a Channel Cutter feature - and the cutter rig correct for this type.

The full keel has a properly developed NACA foil shape for maximum lift and minimum drag.

Construction is all steel for the hull and decks. The cabin top and Pilot House upper portion are cold moulded wood from the window sill upward. These are weight saving measures, very appropriate with relatively narrow beam.  The fantail stern is a natural for any chine hull, and provides a classic grace that has become so uncommon these days..!
 

Particulars

Particulars of the vessel are:

 

The Rig

The rig is extremely robust but simple. The spars are made using standard schedule 40 aluminum pipe for the mast, spreaders, booms, and bowsprit. They are welded shut and totally water tight. The mast and bowsprit are tapered at their ends. Other spars have standard pipe weld end-caps. The gooseneck is stoutly fabricated aluminum plate, with a Type 316 Stainless pin. The mast fittings are all welded aluminum, fabricated and welded in place. No fastenings. All spars will float...!

Shrouds and stays will (ideally) be heavy duty galvanized improved plow steel 7 x 7 IWRC, or can be one size larger using a 6 x 7 construction having a fiber core. The preferred end treatments are to have all spliced soft eyes at the mast, with poured socket fittings at the lower ends, then toggles and turnbuckles. The backstay is fixed (i.e. permanent backstay). Stainless wire can be used if desired, and will ideally be of the same construction, but more often will be 7 x 19 due to availability issues. The bobstay and bowsprit whisker shrouds are chain, with turnbuckles.

Those details are all quite uniformly the case for most of my designs – aimed at rugged strength for cruising, and simple n0-fastenings construction for extremely low maintenance.

The running rigging is also very simple. If desired, the mast can be arranged on a tabernacle for lowering on canals.
 

Interior

Briefly described, the interior has a large double berth forward, arranged as a large "V" berth. Aft of that is a settee on either side of the mast. A table is hung on the aft face of the mast and serves both settee seats. The table is arranged with fold-down leaves, and has an 8" wide fixed center portion for storing wine bottles or other similar things.

The galley is aft of the settee, and is located on port and starb'd sides, so it is quite generous in size. Just aft of the galley is a quarter berth to port. Aft of the starb'd part of the galley is a good sized head compartment.

This layout is quite similar to that of the ZEPHYR 42 Layout, except that there is only one quarter berth on the RAVEN 42, which is located to starb'd in place of the ZEPHYR's chart table. Another difference is that on the RAVEN 42, the port and starb'd settee are full length berths as well. Thus the galley, head, and quarter berth are located approximately another two feet farther aft than on the ZEPHYR 42.

The RAVEN pilot house extends over a portion of the forward trunk cabin, which effectively creates a "dashboard" forward. Below the "dashboard" to starb'd is the head compartment, and to port the quarter berth extends below the port side of the pilot house..

The pilot house is simple: there is a pilot seat and steering station located to starb'd. A long chart desk is located to port, which houses the quarter berth, accessed from below. The pilot house height is intentionally kept as low as possible in order to be less of an obstruction to steering and sailing from the aft exterior cockpit.

Below the pilot house is the engine. The engine space is sized as it would be on a sail boat, i.e. small...! This is by intent, and in fact does not limit access as much as one might imagine. The pilot house sole lifts up, and the companionway ladder to the main cabin also is arranged to be removable. This exposes the entire engine space for routine maintenance.

Below the exterior aft deck is quite a large lazarette. Access to the lazarette is provided via doors in the aft end of the pilot house. A hanging locker is also located below the aft deck, with easy access from the pilot house.

The accommodation plan is sketched but has not been put online. Prices and ordering information can be found at www.kastenmarine.com/plans_list.htm.
 

Propulsion

The originally specified engine was a 4 cylinder Lister 55 hp with Hurth gear. This allows Raven to exceed her most efficient "voyaging" speed under power, i.e. at 55 hp, an S/L of around 1.2 or around 7.3 knots can be reached. This is above what is considered to be an efficient voyaging speed (ordinarily S/L 1.0 to S/L 1.15). For example at S/L 1.1, speed is around 6.7 knots, which is the "sweet spot" for voyaging. At that speed, approximately 20 hp to 25 hp are being used, and the engine is not really working very hard. Thus, we can see why a smaller engine is actually plenty, in particular on a fully capable sailing vessel.

Alternate marine diesel choices would ideally be in the range of from 50 hp to 80 hp. At around 75 hp an S/L of 1.35 can be reached, for a speed of around 8.25 knots. This is of course not an especially efficient speed, since the engine will then be consuming nearly three times the amount of fuel as at an S/L of 1.1...! However if "full power" capabilities are an absolute requirement, approximately 70 to 80 hp would be about right for a 100% power vessel. One highly suitable engine in this power band is the Volvo D2-75, which is quite compact and comes complete with its own gear.

In terms of efficiency, much depends upon the propeller choice (fixed pitch, feathering, or controllable pitch), its diameter, and the reduction ratio chosen.

Alternate gear choices might include Twin Disc, ZF, PRC, or Dong-i, depending on reduction ratio desired. Another option is to make use of a fully feathering Controllable Pitch propeller. Our favored way to achieve this is to use a standard reversing marine gear combined with a hydraulic pitch control servo unit from Nogva or West Mekan. This allows fully feathering the blades for very low resistance sailing, and is to be highly recommended. A controllable pitch propeller also allows the engine to be fully loaded at nearly any rpm. For more information about this option, please see our article on Controllable Pitch.
 

Tanks

As configured, the RAVEN 42 carries 150 US gallons of water and 80 USG of fuel, of which 10 USG is within a clean header tank. The water tanks and the fuel tanks are all integral with the hull. For more about our rationale for integral tanks, please see my article on Integral Tanks. All fuel and water tanks have generous man-hole covers, as well as separate clean-out ports. The waste tank holds 30 USG and is make of heavy wall polyethylene. This tank is non-integral so that it can be removed if needed.
 

Summary

Raven is in my view quite a fine design - an ideal motor sailor with a fully capable engine and an ample stash of fuel... but also a fully capable sailing vessel.  With sufficient engine power, fuel, an enclosed pilot house and a fully capable sailing rig, Raven is a true "motor-sailing vessel" in every respect. In other words, not a 50-50 compromise, but a 100% capable sailing vessel as well as a 100% capable motor yacht.
 

Please see the  AVAILABLE BOAT PLANS web page.

Home  |  Intro  |  Our Design Process  |  Stock Design Info  |  Motor Yacht Designs  |  Sailing Yacht Designs   |  Prototype Designs
Plans List  |  Articles  |  Our CAD Design Stream  |  Maxsurf  |  News..!  |  SITE MAP..!  |  Site Search  | Design Team  |  Contact Us