Sunday, 6 October 2013

Idealists, Optimists and Ergonomicists

Vitruvian Man (photo L Viatour)
I've never been on a boat that didn't have standing headroom. Taking measurements from my study plans, I've tried to mock up what the interior seating arrangement of a Cape Henry might be like. I'm slightly over 6ft tall, and I'm a bit worried about not being able to sit upright. I picture myself anchored in an idyllic bay for the night, reading a book and sipping a whiskey by candlelight with my head wedged at a 45 degree angle against the cabin roof, the centreboard case digging into my shins. Ideally I'm hoping for a comfort level similar to the back seat of a Ford Focus, but I'm not really sure what to expect. 

There's a company called Cornish Blue Sailing in Falmouth Bay that charters out similarly sized Cornish Shrimpers and Crabbers and we really should have planned things better and taken a weeks holiday on board one of them just to make sure this size of boat would work for us. But it's too late now! So I'm trying to be optimistic and put my faith in Messrs. Dix and Roe. 

At the same time, the Water Craft articles leave me with a niggling doubt. Mr. Goad found the cabin seating arrangement to be perfectible and did a fair bit of tweaking of the ergonomics. I want my boat to be perfect too, so all of this is preying heavily on my mind ... 

The Internet is an astounding place, and the variety of information that can be found never ceases to amaze me. And while those who design small car interiors for a living are not terribly generous in sharing their conclusions, others are. People who make chairs have obviously thought a lot about the "correct" dimensions for comfortable seating, and there has been much academic research into office furniture. Thanks to these furniture makers and researchers at Cornell University and elsewhere I've discovered that the ideal chair for the average 50th percentile human being has a seat height of 44 cm, a seat depth of 41.5 cm which is 7 degrees lower at the back, with a seat back height of 36 cm and a reclining angle of 10 degrees. 

Chair according to Wood Magazine
Unfortunately I'm taller than the 50th percentile human being and the interior dimensions of our boat preclude fitting this ideal chair anyway, so many late evening hours are spent taking measurements and sketching the slight adjustments and alterations that will be required to adapt this perfect seat to something that will fit both me and the boat. 

After much deliberation it turns out that in order reach perfection, we'll have to raise the seats by precisely 5 cm, move the seat back in by 15 cm with a vertical rise, and add a wedge-shaped cushion 50 cm high with an angle of 11.3 degrees slope. I sketch out my perfect seat, scan it, and send it to Tiernan. 

My design includes cave lockers in the vertical seat backs, similar to the Vivier designed Méaban, but Tiernan is not crazy about the idea of having to shift what will end up being big, heavy seat-back cushions in order to reach the contents. And he's not crazy about the idea of having to store the big, bulky seat-back cushions when it's time to sleep. Once again I'm discovering that everything on a small boat is a compromise. Adding something here means taking away something over there. And the smaller the boat, the bigger the compromise. 

Back to the drawing board?
Another flaw in my design is that it requires separate pillows for sleeping. Having items on a small boat which serve dual purposes result in huge savings in occupied space and a corresponding reduction in clutter. One of the big plus points of Dix's design is the feeling of openness and space. It gives the impression of being on a much bigger boat, so anything that goes against this principle will make for a more cramped and claustrophobic feeling. And I really dislike clutter.

The sleeping thing is a big issue because normal seats are not wide enough to sleep on, but a seat that is wide enough to sleep on is generally too deep for comfortable seating. It's a real balancing act. 

Tiernan has also studied ergonomics, and the end result of our discussion is that we agree to "wait and see". Once the boat is turned over we'll have a much better idea of what will work and what won't.