Monday, November 26, 2012

On Yacht Design

New Bern, NC

Well, we're back on the boat after a week celebrating Thanksgiving with family.  We had a great time.

I engaged in an exchange on the Westsail Owners Association web site about providing heat on the boat during winter.   The discussion reminded me of how different the needs and priorities of the various boat owners.  It would be next to impossible to find a solution that came close to satisfying everyone.  That is the challenge faced by yacht designers.   They need one or more designs that fit the needs of large groups, if not everyone.   They make numerous choices, each of which is a trade off of one feature versus another.   Every time I think of changing something, I become very cautions.  I fear not thinking of all the trade off consequences before acting.  I trust most the skillful designers at the Westsail Factory in the 1970s.

Here are some of the most obvious design tradeoffs on Tarwathie.

  1. She is a blue water boat, optimized for prolonged ocean crossings.  The most obvious features there are: (a) A double-ended hull with a full keel is better able to track a straight lin in heavy seas.  (b) A small cockpit that drains rapidly if filled with water.  (c) high bulwarks around the edge that keep crew and gear more secure when at sea.  (d) The bulwarks can hold tons of water at a high center of gravity.  Therefore, we need the classical sculpted dips in the bulwarks fore and aft.  They form scuppers that allow water filling the decks to the top of the bulkheads, to drain overboard in just 2-3 seconds.  But the lines of those scuppers are classic and beautiful making the boat more attractive.
  2. We have a bowsprit and a boomkin that allow us to carry bigger sail area than we could without them.  A boat with the same displacement could also be designed with a longer hull rather than the bowsprit/boomkin.  I suppose the longer hull has more friction (wetted area) but I'm not sure what the other tradeoffs are.  I'll bet a knowledgeable blog reader will let me know.
  3. We have a hard dinghy optimized for rowing.  Our Fatty Knees dinghy is perhaps the best modern rowing dinghy anywhere.   A blue water boat needs a very secure way to carry such a dinghy offshore.  We have custom teak chocks that allow us to carry it very securely under the boom.   That has the side effects, (a) the stern of our dinghy interferes with our sight forward, and (b) we can not mount the main sheet and traveller on the cabin top.  We have it instead in the cockpit; a most inconvenient spot.
  4. The Monitor Self Steering gear is much more reliable than any electronic autopilot.  Circumnavigators favor such reliability and simplicity above other features.   Because of the monitor, we can not have stern davits for a dinghy, nor large solar panels mounted on an arch.
  5. In the cabin, we have a table that very easily folds up and stows vertically on the bulkhead.  That deprived us of any place near the floor to mount the cabin heater.  On the other hand, it makes our cabin very spacious and comfortable, table up or table down.   Libby and I think that we have more open room, and more comfortable space for two people to lounge in the cabin than just about any sailboat of and size that we have ever seen.   More details here.
  6. A pilot berth that pulls out to make a double bed in the main cabin.  That deprives us of some space that could be used for stowage, or bookshelves or whatever.   It also allows us to never have to use the V-berth for sleeping unless we have guests. We like that trade off very much.
  7. The main sheet placement also prevents us from enclosing the cockpit in canvas and windows.  That, plus the small size of the cockpit and the placement of winches and instruments, deprives us of any comfortable place to lounge in our cockpit.  On many other cruising boats, the cockpit is like an extra room -- one which is very pleasant in the early morning or late evening.  While under way, a second person in the cockpit gets in the way.   As a result, Libby and I spend many more hours in our cabin and fewer in the cockpit compared to our friends.
  8. Tarwathie has two huge lazarette lockers, port and starboard under the cockpit seats.  On other W32s, that volume is occupied by 40 gallon fuel tanks port and starboard. We have 20 gallon wing tanks, port and starboard, for diesel that sit up against the bulkhead.  In one of those lockers I have a storm jib and storm trisail, plus my paint locker and stowage for chemicals and maintenance stuff.   In the other, we carry lines and cordage, lots of line and cordage, plus flares, chafing gear, and spare hardware.  I have a hard time imagining where we would stow that stuff if we did not have those lockers.   The trade off is that we carry only 1/2 the fuel, and that the engine compartment is smaller and more cramped than other W32s.  The double ended hull is also narrow back there, so we have much less room for things like extra batteries or hot water tanks, compared to other sail boats.  I also have a hard time preventing water leaks around the seat hatches.  
So, despite the fact that we do mostly coastal cruising, not blue water cruising, Libby and I are quite comfortable on Tarwathie.  We envy the nicer cockpits that our friends have, but we treasure the more comfortable main cabin/salon that we have compared to all other sail boats.  Were we just lucky to find a cruising boat that suits us so well, or has our life style adapted to make best use of what we do have.  I'll wager that it more of the latter than the former.

Once again, hats off to those smart yacht designers who made so many smart choices up front.


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