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The 50' Classic Motor Yacht


50' Motor Yacht RENEGADE - Kasten Marine Design, Inc.
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Exterior Profile | Exterior Deck Plan | Interior Profile | Interior Plan | Exterior Sail Plan
Perspective Forward | Perspective Aft | Lines Forward | Lines Aft

Copyright 2005 - 2019 Michael Kasten

General Concept

The 50' Renegade and the 49' Quinn, along with their smaller sister the 43' Moxie and their big brother the 60' Peregrine, represent examples of my own ideal Motor Yacht type.

In fact, Renegade, Quinn, Moxie, Peregrine... these 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: between Seattle and Juneau, on US rivers and lakes, the US Intra-coastal Waterway, Florida Keys, fjords of Norway, the island coast of Chile, Patagonia, the Great Barrier Reef, Indonesia... Overall height is kept under 3.5 meters in order to also allow cruising the canals of Europe.

For my own use, a more perfect type of power boat is difficult to imagine...

The Layout...

The interior and on-deck layout of Renegade is exactly as with Quinn. At 50' LOA the layout is not at all crowded, and that is very much as we have intended...! Below, the interior is optimized for two, however the arrangement allows for occasional guests.

The galley is over 7 feet long, and is arranged in a long fore-and-aft "U" shape with a clear 3' x 7' counter on center. If you take a moment to actually measure that, you'll find it's quite huge! Opposite the galley is another equally long counter-top with laundry below - which is arranged to also function as a large desk / project table.

Amidships is a comfortable lounge / saloon with an actual coffee table on center! Forward of the saloon is a head to starb'd and bath / shower to port. Forward of those, the master suite having a king size island style berth and lots of storage. The whole idea is to make life aboard extremely comfortable for two, but to still accommodate occasional guests.

On deck, the pilot house is quite big. A generous covered aft deck provides comfortable seating from which to enjoy the waterfront. The aft deck could be screened in if desired or even enclosed by awnings for cooler seasons. The large fore deck is perfect for lounging as well as for storage of a shore boat while under way. A second shore boat can be stowed on the house top as shown.


Due to the simple shape and relatively light displacement, Renegade will be inexpensive to build for her length, especially so considering the amount of living space provided. As with all the vessels in this series, Renegade is long and lean so horsepower requirements and fuel use are very modest, a further contribution to long term economy.

The choice of steel for the structure on Renegade has primarily been to keep costs as low as possible as well as for sheer ruggedness. The fore deck and pilot house top structure are cold moulded wood. If built in aluminum, the house top and fore deck would also be of aluminum.

Whether steel or aluminum, all parts will ideally 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

Compared to Quinn, Renegade has slightly more displacement, so has a slightly greater fuel capacity. Per the Beebe algorithm, at passage making speeds of 7.5 knots with 700 gallons of diesel fuel, assuming a 12% reserve and a specific fuel consumption of 16 hp/gal/hr, range for the 50' Renegade will be approximately 3,000 miles, and at 7 knots, around 3,500 NM. If built in aluminum, the weight of structure would be approximately 7,000 pounds less, so there would be the possibility of carrying a bit more fuel for increased range at those speeds.

An engine of 75 hp will push the boat along at a "normal" hull speed of around 9 knots (at S/L 1.34). Due to being long and sleek however, Renegade has a much higher speed potential and should be able to easily achieve around 11.5 knots. In the fully loaded condition the power required for 11.5 knots is approximately 135 hp. This is well within the intermittent rating of the John Deere or Lugger four cylinder turbo diesels, and certainly for long range voyaging under power - at around 7 to 8 knots - this would be the ideal engine size.

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.

Imagine that... a 50 foot Motor Yacht with a 4 cylinder engine... This is what we mean by economy!

A Sail Rig on A Power Boat...??

An optional sail rig has been drawn. The sail rig is of course not meant to win sailing races. It is for the sheer fun of sailing, for use as a get-home strategy in case of engine failure, and in order to extend the range under power when winds favor.

If Renegade were to be used primarily as a sail boat, sail area would be greater and the keel configuration would be optimized for that purpose, possibly making use of a deeper keel and / or a centerboard. In the illustration above the primary objective was for ease of handling, therefore the Junk rig was chosen. For more information on the advantages of this type of rig, check out our web article on Junk Rigs.

With the sail rig, the weight of the rig itself helps attenuate rolling motions, especially while actually sailing. Without the sail rig, a paravane rig would be provided for roll stabilization, however even if the sail rig were chosen, paravanes would still be an option.

The masts are stepped in tabernacles, allowing them to be easily lowered for canal cruising.

In Summary

For a couple seeking a comfortable life afloat, the 50' Renegade and the 49' Quinn combine all of the basic necessities with the luxury of a spacious and un-crowded interior. In terms of finding the perfect personal motor yacht, these boats are my own first choice.

To me, the primary appeal of these designs is the excellent accommodations for two, combined with simple construction and economical powering. Guests can be accommodated by conversion of the pilot house dinette into a large double, or by conversion of one of the saloon settees into a double. The covered after deck offers protection from sun and rain; the gourmet size galley and big saloon allow the luxury of fine dining afloat; the large sleeping cabin forward.... and there is even a bath tub!

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

Also, check out the article on Renegade's smaller sister, the 43' Moxie written by Steve Knauth in Soundings Magazine.

50' Motor Yacht RENEGADE - Kasten Marine Design, Inc.

Other designs in the "Peregrine / Renegade / Moxie" Family:

36' Molly | 43' Moxie | 49' Quinn | 50' Renegade
61' Peregrine | 82' Peregrine | 100' Amazon | 164' Peregrine
60' Pennywise Trimaran | 70' Peregrine-on-Thames