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The 100' "Bermuda" Skipjack

A Bermuda Skipjack..?
Large Aft View | Large Fwd View | Larger View with Sails..!

Copyright 2008 - 2011 Michael Kasten

General Concept

Based on a request for a classic shoal draft charter yacht of around 100 feet on deck (approximately 31 meters) with an easy to handle rig (no gaffs or tops'ls), this seemed the ideal combination. Originally planned for construction in wood, the idea was to take advantage of local materials and trainee labor to create a signature vessel for a maritime town in Eastern Canada or the far Northeast USA.

Given the single chine shape, this hull form would also be ideal for aluminum or steel construction. The Skipjack is perhaps the ultimate in terms of being an aesthetically refined traditional sailing vessel which has always had a single chine hull shape. No one argues with the shape, since these vessels have never been otherwise.

Would the original flat, wide, low freeboard Skipjack hull form actually be suitable for the open ocean..?

Not if taken literally. Therefore I adapted the hull to a new shape for its new ocean-going purpose, all without violating the outstanding aesthetic character of the original Skipjack types. My goal in so doing was to create a charter-worthy yacht that could be sailed on the oceans of the world, that preserved the original character of the type, and that could be very simply built.

The first concepts in this design series were our 51' to 70' Skipjack prototypes. Taking those concepts a step further has led us to this version at 100 feet on deck. Yet another version of this 100' Skipjack type are our 100' to 120' Cargo Skipjack prototypes.
 

Seaworthiness

In order to become a good yacht for the open ocean, the original Skipjack hull form has been made much less flat and wide for its overall length; the hull has been made deeper; and the topsides have been given considerably more freeboard. This latter trick was accomplished without aesthetic penalty by raising the deck up to the height of the rather substantial bulwarks of the original types, and then placing a typical bulwark and toe rail above that.

Per the rigorous requirements of the EU-RCD, specifically the STIX criterion as outlined in ISO-12217, as long as the CG can be kept low, the adaptation of the Skipjack shown here has proven to score well within Category A, i.e. all ocean.
 

Hull Form

Given that this design still has somewhat more beam than would a typical yacht, the righting moment is quite excellent, providing for stiff sailing without excessive depth of keel. The long straight keel, with slight 'drag' over its full length, provides for the ultimate in tracking at sea, while not offering too much keel below. This combination is the very best at avoiding being broached and tripped by a sea. With this keel configuration a centerboard is planned for, in order to provide more 'bite' to windward.

Alternately, if the keel were shaped differently the ballast could be lowered further. This would not necessarily make the keel deeper overall, it would just become level on the bottom, but still raked downward in the forward third. In other words, starting aft, the keel would remain at the full depth of the rudder heel for approximately 2/3 of the keel length, and then would slope upward to the depth of the stem forward. With that configuration, it would not be at all necessary to use a centerboard, vastly simplifying the whole thing, but still able to sail in relatively shallow water.

The overall benefit of the Skipjack shape is its refined traditional aesthetics, combined with an economically built and easily driven hull form. Inevitably comes the question then... 'Isn't a rounded hull faster..?'

We answer this question the same way every time: A single chine shape has very slightly more wetted surface, therefore more sail area is indicated making it the equal of a rounded hull. In section, the single chine shape has just a bit more 'shoulder' below the waterline which allows the boat to carry that extra sail area without penalty in terms of heel. At speed, in particular when sailing fast down wind, the chine shape is actually faster due to being able to develop greater dynamic lift.

The single chine shape has other advantages... primarily that of being quite simple to build in metal, therefore requiring considerably less labor. In terms of speed per dollar, since one can afford to make a single chine vessel longer than one could afford to do with a rounded or multi-chine hull form, there are substantial performance gains to be had.

In wood, of course the Skipjack type of construction would be ideal. However, if so desired, the hull could be made rounded and made even simpler to build using all steam bent frames.
 

Sailing Rig

For the rig, in order to make good use of modern materials, the spars would either be hollow if made of wood, or would be fabricated using welded aluminum pipe. The sail materials would be Dacron, and a performance oriented sail cut would be used.

Of course the rig must be kept rather low-aspect for this adventure, but it need not be shy on sail area. As we can see in the above image, a modified Bugeye or modified Bermuda rig arranged as a three mast schooner would probably be ideal. Aesthetically this seems to provide just the right dose of tradition, while also providing excellent performance in an easily handled rig.
 

Summary

This is just how the working sailors of yore would have adapted such a vessel to its new purpose, i.e. that of a safe, easily built ocean sailing craft. Whether it is an "exact" replica of a fat old oyster boat is a completely silly question. Given the proper attention to detail, no-one would even notice...!

Fast cruising, windward ability, seaworthiness, simplicity of construction, ruggedness, and a reasonable cost to build and maintain... these have been the primary goals of the design. At least in my view, those goals have been superbly met.

For more information, please inquire.
 

100' Bermuda Skipjack