Messing about in boats since 1975.  Online Since 1997.

Kasten Marine Design, Inc. Logo - Copyright 2017 Michael Kasten

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

Please see the  AVAILABLE BOAT PLANS web page

The 22.5' Tug Yacht

'Li'l Boojum'

The 22' Pocket Tug-Yacht - BOOJUM - Kasten Marine Design, Inc.

Perspective Aft | Perspective Forward | Perspective Above Aft
Li'l Boojum Exterior Profile | Color Profile | Li'l Boojum Interior Layout

Copyright 1999 - 2016 Michael Kasten

General Concept

The idea behind the Boojum series of ultra small Tug-Yachts was to create the smallest possible trailerable pocket "trawler yacht" capable offshore voyaging. This version, at 22.5 feet overall length, is the smaller sister to the 25 foot Boojum.

Why are there two vessels so close in size?

Really they are not so close in terms of displacement. The 25 foot version has a large enough carrying capacity for the fuel required to make the run from the US Pacific coast to Hawaii, one of the longer ocean voyages between fuel stops. This smaller 22.5 foot version was the "parent" vessel for the larger Boojum.

At 22.5 feet overall, "Li'l Boojum" has plenty of fuel capacity for somewhat shorter ocean trips of around 1,200 miles. Li'l Boojum has a much lighter overall displacement; a lighter engine; an overall smaller stature for easier trailering; and a lower price tag. Nevertheless, this smaller version still has all of the good features of the larger boat, including the twin keels for taking the ground gracefully.

Particulars are: 22.5' LOA x 21' DWL x 8'6" Beam x 3'9" Loaded Draft. Displacement will vary from around 11,500# to a full load capacity of 15,500# with all tanks full, and the boat ready for a coastwise voyage, complete with stores for two people. Range is in excess of 1,200 NM at S/L 1.15 in order to permit long coastal voyages.

The engine should have around 25 to 35 hp, and ideally should also have an integral Sabb controllable pitch propeller. Several engine candidates come to mind, however the overall weight budget for the engine and gear is around 500 lbs. total.

Hull and pilot house construction are aluminum. Portlights are glass. Pilothouse windows and larger portlights are Lexan except for the center forward window which is glass to permit a wiper arrangement. Pilot house top is cold molded wood for added headroom, for lightness, and for ease of mounting hardware in the future.

Hull Form

As with the larger Boojum, 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 8' 6" to allow trailering without being a "wide load." Deck structures have been kept as low as possible to provide for a low center of gravity, and also to permit trailering on the US freeway system. Still there is standing headroom in the pilot house for anyone under 6 feet of height.

Bilge Keels

The bilge keels are partially used as "wing" fuel tanks, and they will also serve as a location for the ballast. The bilge keel configuration offers the maximum comfort at sea for this size vessel, in combination with an exceptional range of positive stability. The keels permit sitting upright on the mud, or on a trailer (a "dive-ladder" is placed to starboard for boarding from the water, or from land while aground). The bilge keels also provide both roll dampening and increased lift for windward sailing under "auxiliary sail power." For more information on the rationale behind Boojum's bilge keels, check out: Boojum's Bilge Keels.

The Boojum 22 would also be possible without the bilge keels and would be much easier to build. Please see the "Perspective" links above. This would permit other hull construction materials, such as stitch and glue plywood or fiberglass.

Interior Arrangement

The layout makes use of a low forward cabin; a 'midships wheel house; and an aft sleeping cabin. The forward cabin top extends the full width of the ship for the whole cabin length, extending fully to the height of the main bulwark and providing very large interior space to the "saloon." The raised forward deck has other benefits... it also yields the largest open deck area, the greatest forward freeboard, the most reserve buoyancy forward, and the greatest range of stability.

A trunk cabin is located aft of the wheel house to house the sleeping quarters, clothing, and miniature library. Within the aft cabin is a permanent queen size double berth which does not need to be made up each day out of some other joinery feature - it's always there...

In the 'midship pilot house, the galley to port and the pilot seat and wheel are to starboard. The pilot house offers excellent visibility in all directions. Deck access is via a sliding door to starboard. The "dashboard" forward of the wheel holds instruments and engine controls. Some instruments are mounted overhead as needed. Chart stowage is under seats and in back of cushions in the forward compartment. The galley includes a small stove and a sink with manual water pump. There is a refrigerator under the pilot seat (starboard side). Storage is provided for dishes, flatware, knives and cooking tools, a set of nesting pots and pans, and a small pressure cooker.

The head is small, but effective. It's tucked below the forward part of the pilot house sole, so is completely out of the way.

Can there be a more ideal extra small power boat for trailering and coastwise cruising? I think not!!

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