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The 43' Classic Trawler-Yacht


43' Trawler Yacht - ROBERTA - Kasten Marine Design, Inc.
Interior Profile | Interior Plan
Perspective Forward | Perspective Aft | Port Forward | Port Aft

Copyright 2009 - 2016 Michael Kasten

General Concept

The 43' Roberta shares a general layout with a family of our motor yacht designs, starting with the 43' Moxie and, extending up to their bigger brothers, the 49' Quinn, the 50' Renegade, and the 60' Peregrine. A very similar close sister to the 43' Roberta shown here is the 43' Roberta Jean. Each of these designs represent examples of my own ideal Motor Yacht type, in particular in terms of the long raised fore deck, aft-located pilot house, and fantail stern...!

In fact the Moxie, Quinn, Renegade and Peregrine designs were all created with one client in mind: myself...! Thus each of them represent the ideal type of boat for coastal cruising nearly anywhere along the coastlines of the world.

In the case of the 43' Roberta we have been asked to create a design that uses the same excellent interior layout as that of the 43' Moxie, but with a slightly heavier displacement hull form in order to provide a little more elbow room throughout. In this case, we've chosen a hull type from our lineage of Tug-Yachts: the Boojum, Buster and Nidaros designs. These designs have a relatively much deeper body for the sake of maximum carrying capacity and sea-going comfort. Still, they share the excellent fantail stern - a natural for a metal boat - and a rather plumb stem, very much in line with the Moxie to Peregrine series...

Overall height is kept under 3.5 meters in order to also allow cruising the canals of Europe.

Roberta vessel particulars are:


One of the main features planned for Roberta was to have a large sheltered aft deck for part-time outdoor living. The aft deck could even be screened in or enclosed by a canvas / vinyl dodger in cooler weather. A large open fore deck allows plenty of space for sun tan adventures and for stowing the shore boat and other gear.

Inside, the layout is as conservative as possible in order to keep boat size within limits, but still extremely comfortable for a couple and occasional guests. The settees can be made into berths, as can the pilot house dinette. Combined with the aft-facing seat on the aft deck, conceivable there is sleeping space for seven...!

The galley is quite generous, occupying a generous part of the port side aft. There is a large head / shower opposite the galley to starb'd.


The choice of aluminum for the structure on Roberta has primarily been to keep weights as low as possible as well as for sheer ruggedness.

All parts are intended to be NC cut by plasma arc or water jet. The NC cutting process leverages the work already done to create the computer model, allowing structure to be easily defined directly from that computer model. The resulting "boat kit" makes for very fast assembly. Once the parts have been pre-cut and delivered, the frames and other internal structure are quickly erected, the stringers placed, and the plating applied.

Power And Range

As with all the vessels in this series, Roberta maximizes the WL length in order to have the most boat speed on a given length of vessel. Horsepower requirements and fuel use will be quite modest, and any of the naturally aspirated small 4 cylinder diesel engines should suffice amply for propulsion.

Compared to Moxie, Roberta has a much deeper hull form, therefore greater displacement, and has been given a slightly greater fuel capacity in order to achieve the same approximate range under power. Per Beebe algorithm for range calculations, Roberta should achieve around 3,000 NM at 7 knots on a fuel capacity of 800 USG with 12% held out as reserve.

A 4 cylinder John Deere engine will be quite sufficient for this vessel. If one were to prefer a naturally aspirated engine, the John Deere 4045 at around 75 to 85 hp should push the vessel along at S/L 1.2 to 1.32. If using the turbo version, at 105 to 130 hp, there would be plenty left over for punching into the weather.

The engine shown is a John Deere 4045 TFM, mated to a Sabb controllable pitch gear and Helseth self-contained shaft system having a three blade controllable pitch propeller.

In Summary

For a couple seeking a comfortable life afloat, the 43' Roberta combines all of the basic necessities with the luxury of a spacious and un-crowded interior. In terms of the perfect interior for a personal motor yacht, the Moxie - Roberta - Quinn - Renegade - Peregrine designs are my own first choice.

To me, the primary appeal of these designs is the excellent accommodations for two, even in the larger sizes. Guests can be accommodated by various means, all of which do not require there being a separate dedicated cabin for guests. The covered after deck offers protection from sun and rain; the gourmet size galley and big saloon allow the luxury of fine dining afloat... Combine that with simple construction and economical powering... it is a winning combination to say the least!

For more information on these vessels, please contact us...

43' Trawler Yacht - ROBERTA - Kasten Marine Design, Inc.
Click for Larger Image

Similar Designs and Prototypes in this Tug / Trawler Yacht Series

Tug Types
Boojum 22 | Boojum 25 | Boojum 30
Terrier 32 | Talisker 32 | Nidaros 38

Trawler Types
Sweet Okole 30 | Buster 30 | Boojum 43
43' White Buffalo | Roberta 43 | Roberta Jean 43 | Roberta Jean 47
Far Horizon 40 | Far Horizon 43 | Far Horizon 46 | Far Horizon 50 | Far Horizon 54

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