Messing about in boats since 1975.  Online Since 1997.

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The 48' Aluminum Trawler Yacht


Greatheart 48 - An Aluminum Trawler Yacht by Kasten Marine Design, Inc.
Greatheart Exterior Profile | Greatheart Interior Profile and Arrangement
Perspective Aft | Perspective Forward

Copyright 2000 - 2011 Michael Kasten

General Concept

The 48 foot Greatheart has a hull form similar to the 46' Gulliver and the other vessels in the Greatheart series. A quick look at this hull form reveals very adequate overhangs fore and aft, much like a fishing vessel would have.

The Pacific Northwest fishing vessels have indeed been the inspiration for these hull designs, however the Greatheart 48 is quite a lot more sleek than those parent types. See below for a description of the genesis of the Greatheart family of designs.

The GH 48 has a waterline length is 39.7 feet light, and 41 feet loaded. Displacement will be around 31,000 lb. light and around 39,000 lb. loaded. Beam is 12.5 feet.


Sails are provided both as emergency get-home power and as roll dampening devices. Greatheart makes use of a very conservative ketch rig. There are twin keels of a fairly conservative size for the sake of sitting on the mud, to carry a small quantity of ballast, for enhanced rolling resistance, and for the sake of providing windward performance under get-home sail power.

Additional roll attenuation is provided via paravanes. It is anticipated that due to the sail rig and bilge keels, that the paravanes will be used considerably less of the time than if the vessel were not so equipped.

Power required will be around 80 to 85 hp for ocean travel. Engine choices are the very capable 4 cylinder John Deere, the very stout and well engineered 4 cylinder Lugger, or the long lived 4 cylinder Cat 3304-B. Any of them will be suited to world voyaging. The JD or Lugger will provide a bit of weight savings over the CAT engine. The JD and Lugger also provide close to the same horsepower. We have specified the John Deere for the best all around combination.

For the greatest number of options under power or under sail, we have also specified a Controllable Pitch propeller and gear. First cost is not much different than top grade fixed pitch gear and propeller equipment so there is little rationale in favor of FPP, in particular given the excellent possibility of motor sailing with the GH 48.

The Greatheart hull shape is very light in weight. At top speed Greatheart will achieve around 9 knots. Range is calculated to be over 3,000 NM using around 650 gallons of fuel at a typical voyaging speed of around 7.25 knots.

Illustrated Interior

The layout below reveals a kid's or guest twin bunk stateroom aft, with two quarter berths and a big school / office desk on center facing aft. There are two settee seats in the Pilot House, intended to seat four adults comfortably.

Forward and below, the galley is located on both sides just forward of the companionway. Immediately forward of the galley there are a pair of easy chairs, one to port and one to starb'd, which allow the "ship's library" and the galley's social area to be rolled into one.

Forward of the ship's library is a head located to port and a dedicated shower compartment located to starb'd. The shower doubles as a true bath tub, and has been given a convenient teak-slat seat outboard. The forward stateroom is for the owners. The owner's cabin features an island berth right forward and ample storage within two hanging lockers and the very large area below the berth.

Alternate Interior

I have worked out an alternate interior that would not disturb the configuration of the cabins or structure, but which would provide a more spacious dining area located below, and would provide the option of having a second equal stateroom aft. It would be more or less as follows:

Greatheart 48 - An Aluminum Trawler Yacht by Kasten Marine Design, Inc.
Click for Larger Image

Design Summary

The Greatheart 48 profile is both sleek and refined. The intent of the design has been to fit the maximum accommodations into the continuous duty capability of the several readily available and robust four cylinder marine diesel engines. I believe we have succeeded nicely.

The Greatheart 48 has been further developed in several ways. Other prototypes that are shorter in overall length, but which use the same interior are the prototypes, Boojum 43 and the Far Horizon 43. They just have a different hull form wrapped around the same interior layout. Having more or less the same WL length, it is an easy fit..!

Design Genesis

As with our other designs in this series, the hull form for the Greatheart 48 has been adapted from real trawlers - US West Coast fishing vessels which have to operate in all weathers - including in the Gulf of Alaska, a place where the ocean is... well, not so nice. Our aim has been to retain the excellent sea keeping qualities of those working craft, and to refine their lines into 'yacht' form to achieve a more easily driven hull with relatively light displacement. See the following links for vessels in the Gulliver / Greatheart series...

Greatheart 36 | Vagabond 36 | Gulliver 46 | Greatheart 48 | Greatheart 54
Greatheart 60 | Swallow's Nest 60 | Swallowtail 60 | Braveheart 53 | Braveheart 63 | Swallows Nest 70

In order to achieve a proportionately longer waterline and more interior space without increasing boat length, we developed another series of designs based on the same hull form, but with a more upright stem and transom. Combined, this reduces the overhangs and increases the WL length to gain more interior space with less overall hull length. Check out the following links for boats in the Vagabond series...

Vagrant 49 | Vagrant 70 | Vagabond 50 | Voyager 52 | Valdemar 53 | Valdemar 70

For more information on this or other designs, please inquire.

Direct Quote from an aluminum boat owner...
As an owner since 5 years of an aluminum boat I could not agree more with your preference for this material. She is a great boat and requires very little in the way of maintenance. I do a lot more reef snorkeling than the paint, polish, varnish and wax guys!

--Peter Kminek