Messing about in boats since 1975.  Online Since 1997.

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The 20' Electric Launch


A 20' Electric Fantail Launch - Kasten Marine Design, Inc. 

Perspective Aft | Perspective Forward | Perspective Above Side | Hydrostatics Model

Copyright 2015 Michael Kasten

General Concept

Styled after the 25' Boojum and the 18' Pumpkin Seed, the concept behind WHISPER is to create a trailerable electric-launch for harbor cruising under power in complete silence.  A highly capable hull form suited to inshore travel or even coastwise cruising.  Intended for construction in all aluminum alloy, it is quite light, but still extremely robust.  The wrap-around seat and sole are water tight, so there is positive buoyancy even when flooded. 

Plenty of dry storage is accessible outboard of the seat coaming and below the seat via WT ports.  The entire region below the sole is a separate water tight compartment containing batteries, water tanks, the electric propulsion motor, and the steering system.  A WT compartment forward contains a slide-out galley.  The steering station is aft, with enough seating all around for a party of six to eight. 

The images here show a Bimini cover, which could be canvas with a stylish fringe around it, or could be a lightweight alloy or carbon fiber canopy.  In either case, vinyl weather cloths can provide protection when the weather is less cooperative.  Alternately for exploring estuaries, mosquito netting might be very welcome.  In any case, the interior is open and sufficiently large for comfortable camping.

Hull Form

As with the larger boats in the Boojum series, the hull is designed after that of a working tug in order to get the largest carrying capacity within the smallest overall length. Beam has been limited to 7' to allow trailering without being a "wide load" and without requiring a permit.   

Particulars are:

With an average of 400 lb per inch of immersion, WHISPER has sufficient capacity for carrying several adventurers, plus ample stores and water.   The electric motor need not be more than around 10 hp, which should provide a speed of 6 knots.  Ideally, cruising will be done at a slower pace, allowing much greater range.

Can there be a more ideal small motor launch for trailering and coastwise cruising?  


20' Electric Launch "WHISPER" - Kasten Marine Design, Inc.
The Hydrostatics Model - Click for Larger Image

Perspective Aft | Perspective Forward | Perspective Above Side

Trailerable Trawler Article

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
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