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An Incredibly Small Blue Water Power Yacht

Ferdinand 24

Ferdinand 24 - Incredibly Small Pocket Trawler Yacht by Kasten Marine Design, Inc.s
Lines Perspective | Larger Aft Perspective | Side Perspective | Forward Perspective

Copyright 2001 - 2015 Michael Kasten

General Concept

This mini-trawler concept was created for a proposed round the world "race" called the "Magellan Challenge." The rules began with a limit of 22 feet LOA. The goal of the race was to highlight the first vessel to circumnavigate under power in a boat of this size. Multiple legs of the voyage were intended of course. As with many wild ideas, the Magellan Challenge never did take place. Nevertheless... a very interesting challenge.

Having been imagined for the Magellan Challenge, the name Ferdinand was a natural. The all aluminum "Ferdinand" shown here has been extended to 24 feet overall length in order to give just a little more room to the interior throughout. This is a displacement hull form, which favors maximum carrying capacity and long range. Extremely short overhangs maximize WL length and therefore vessel speed and accommodation space below, as will be essential for such a small voyaging yacht.

Particulars are as follows:

Draft is mainly a matter of deciding the expected shoal water limitations versus the preferred propeller diameter for best propulsive efficiency. Larger propellers are better...   Ferdinand is intended to be a truly "Trailerable Trawler" with a very manageable overall height for that purpose.


The displacement to length ratio is fairly high, with a resulting displacement hull speed of around 6.5 knots. At voyaging speeds of around 5 knots, with 200 US gallons of fuel, using the Beebe method the range is calculated to be over 3,200 NM, assuming a 10% reserve. At this speed, power use will only be around 5 hp...! At 6 knots, range would be something like 1,800 NM in the average load condition. At this speed, around 12 hp will be used.

The preferred engine will be as light in weight as possible. Approximately 22 hp will be sufficient for full hull speed, plus a little for wind and weather.  A Lister Alpha diesel would be ideal, especially if mated to a controllable pitch gear and propeller.


Below the pilot house sole is the engine space, in which the engine will be on center, flanked by integral fuel tanks on each side which extend from the pilot house sole to the hull bottom, and from bulkhead to bulkhead. Approximately 100 USG per side is the target.  Below the forward settees will be integral water tanks. Below the forward sole will be heavy duty polyethylene tanks for black and gray water. It may be possible to also place a small clean fuel tank there.


Some means of stabilization will be desired.  Ideally this will be in the form of a simple paravane rig, which can be managed from inside the pilot house.  See the article on Roll Attenuation for more information about this option...


The proposed Interior Arrangement is so-far planned to be very similar to that of the Boojum 25. Since Ferdinand has a large flush fore deck, there is an enormous amount of space in the forward cabin (for such a small boat). Right forward is the head / shower compartment - roughly the size of an airline head compartment.  Just aft of that is a settee on each side much like a sail boat, and a table between. The settees form the "guest" berths. Just aft of the "saloon" is the Pilot House, having a seat to starb'd to accommodate the pilot, and a galley to port. The galley would have enough room athwartships to have a mild "L" or "U" shape.  

Aft of the pilot house is the sleeping cabin, which features a large double berth on top of a wide platform at about waist height from the pilot house. Below that 'sleeping deck' is a rather large storage locker for clothes, extra bedding, lines, fenders, paint, etc. i.e. all the stuff that inevitably finds its way aboard.

What gives "largeness" to the interior is that the cabins all extend all the way outboard to the edge of the bulwark. The aft sleeping cabin is therefore wider than it is long. There would be enough room to have a one foot wide (30cm) shelf on either side of the berth with plenty of storage inside - and... the berth would still be a full king size. Now that is really saying something for a 24' boat...! 

Check out the Interior Cutaway view to get a visual sense of the layout.  Then compare that to the interior of the Boojum 25. The interior of the Ferdinand is considerably larger than Boojum, which is entirely due to Ferdinand's full width house. 

If the boat were lengthened by around 3 to 5 feet, it would allow quite a lot more room in the pilot house area, as well as in the aft cabin. A bulkhead at the aft end of the pilot house would provide complete privacy for the aft sleeping cabin.  Within the sleeping cabin there could be a pair of good sized hanging lockers, one on each side. To see how this would work, have a look at the interior of the Boojum 30

As with the Boojum, heat would ideally be provided by a Wallas forced air furnace or circulating water system. Alternate possibilities are Kabola or the excellent Hurricane heaters. Cooking would be on a two burner stove with oven. My own preference on a vessel of this size would be to use kerosene. Yet another option is to simply use a Wallas diesel range. Though the Wallas range does not have an oven, it is an excellent little stove. 

With well-placed kerosene lamps, the interior would be very cozy indeed.

On Deck

The fore deck will have a hatch leading to the 'saloon' below.  Access to the fore deck is also via an 'awning' window on center.  There is also intended to be a large opening portlight on center aft, plus a hatch in the overhead of the sleeping cabin.  Combined, there should be very good ventilation.  On the foredeck there will also be a windlass, and right forward rollers for a good sized anchor.  If sun-bathing is a priority, the pilot house top is clear.  If that is not so important, the house top provides ample area for solar panels...

Design Summary

The intent of this design has been to fit the maximum accommodations into an ultra small cruiser of no greater than 24 feet LOA. As always, the requirement for excellent sea keeping has encouraged keeping the cabins low in order to minimize windage. Additionally, with a beam of 8.5 feet and a "dry" weight of around 8k lb., the boat will easily be trailered from one cruising site to another, and then stored ashore when not actively cruising - a big savings in marina fees and storage yard rental. Yet another benefit of this arrangement is that the boat when sitting on a trailer will function perfectly well as a camper...! 

As a prototype, the Ferdinand design is as yet unfinished. If this concept is of interest to you, please inquire for more information.

Trailerable Trawlers

Larger Version...!

Given that not everyone wants the smallest possible trawler yacht... a larger model has been made at 35' LOA, and is called 'Big Ferdinand'.  See what you think...

35' "Big Ferdinand" Trawler Yacht - Kasten Marine Design, Inc.
  Click for Larger Image 

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