Pages

Monday, March 29, 2010

Simplicity 42



















This design is finally evolving, and has changed from the early version. The intent remains the same: a simple, practical and reliable ocean cruising boat. Watertight bulkheads fore and aft make her effectively unsinkable. Simplicity is intended as a comfortable liveaboard/long-distance cruising boat, which gives maximum space and comfort for minimum investment and labor. The boat's major features all stem her shoal draft: that has dictated the rig (center of effort as low as possible); the hull form (maximum form stability but sufficient depth and displacement to maintain good reserve stability); and the raised deck (important for both strength and stability).

The hull form is a simple modified v hull, with a flat center section (2.5' wide amidships, which tapers in width fore and aft); the chine between the bilge panels and topside panels is below the waterline for the entire length. There is a wide, shallow ballast keel that bolts to this flat, and on which the boat will sit when beached. Hull depth is 30", while overall draft at the skeg is 36". The centerboard is a simple, triangular shaped board.

Simplicity particulars
LOA: 42'
LWL: 37.5'
Beam: 12.5'
Draft: 3'
Disp: 21,750 lbs,
Ballast: 8000 lbs
Disp/Length ratio: 182
Sail Area

Gaff rig: 818 sq ft (lowers) SA/Disp ratio: 16.99. Sail area with topsail: 940

Simplicity full batten rig (see below): 890 sq ft (main, jib & staysail) SA/Disp ratio: 18.5

















My initial thoughts on the Simplicity rig were to rig her as a ketch, and that may be an option, but a cutter works out well, and the single stick keeps costs down. The full batten rig features a heavily roached mainsail laced to the mast; the mast is hollow, and designed to need little support from the rigging. Battens are easily fashioned from PVC and douglas fir, and lacing the sails to the masts eliminates any problems with raising and lowering the sail, making expensive luff hardware unnecessary. The gaff rig shown above was a later addition, and uses a very similar mast. It will have more sail area when flying the topsail.

She features a raised deck to maximize on stability and interior/deck space, for strength, and for ease of construction. All hull panels are plywood, over plywood bulkheads and frames. Construction is straightforward, using the permanent bulkheads, frames and other interior fittings as molds. Builders have the option of using a traditional chine or using epoxy coving and biaxial tape ("liquid joinery" style); bulkheads and interior joinery can also be secured with cleats or epoxy and tape. The deck is laminated plywood over fore and aft beams.

Power will be about 35 hp, swinging a folding prop.

The concept is based loosely on designs by Ralph Munroe, who lived in Florida beginning in the 1880's. He produced a series of very able, fast, shoal draft boats, the most famous of which was the Presto. Also among his designs were the 52' shoal draft cruising yachts Carib and Alice.



Plans are being prepared. Send me an email (see my website for contact details) to inquire.












The full batten rig for Simplicity is being tested by Bob Wise on his dismasted Cal 34. Here's what she'll look like.

Bob is building the rig over the next few weeks. Read all about it at his blog.