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Friday, February 01, 2008

Forward V-Berth Design

I think we pretty much have the forward V-Berth design finalized. Last weekend I set up a crude mock-up to get a feel for things (very crude) and we are pretty comfortable with the following.
The v-berth will have two single "over/under" berths that overlap. The port side berth will be elevated above the lower one with the head at the bow, with a vertical gap just high enough for a person in the lower berth to get their feet in. The starboard side berth will be lower, just under waist level, with the head at the aft of the compartment. The "floor" for the lower berth will span the width of the compartment, while the upper will simply be attached along the port side of the hull.
At the very peak of the compartment will be an "upper" chain locker. There will be a "lower" chain locker forward and under the lower berth. The chain will be fed by a hawse pipe from the deck. Aft under the lower berth will be a small compartment, elevated above the hull, for storage.
The port side berth, at the foot, will have a "removeable leaf" to facilitate hanging room.
Design Considerations
Here are some of the parameters that drove this design.
Chain Lockers
300 feet of chain can be pretty heavy. The more forward and above the water line it is stored, the more it affects the trim and motion of the boat while underway. Hence, the "lower" chain locker. We think this is probably the lowest and closest to the center of the boat we can get it. Any further and you risk fouling the chain when you deploy/recover the rode. Besides we are pretty close to the thruster tube anyway. There is an "upper chain locker" primarily because that is all we can use the very forward space for.
Bow Thruster Tube
It is the design of the v-berth as to why the bow thruster tube was installed very early. Bow thrusters have their own minimum requirements for depth below the waterline and their position along the cetnerline competes with the hull, a bulkhead and chain storage. Here the tube is just below the floor beyond the door to the compartment. We have just enough room to mount the thruster motor sideways between the tube and bulkhead, under the floor, wether we choose electric or hydraulic.
Pocket Doors
We want a pocket door, as wide as possible, into this compartment. This is dictated by the hull at this point and the width there is about 40 inches, which means we can get a 20 inch pocket door. This further dictates the width of the berths as they must fit in the remaining distance on either side of the door. This makes the upper berth about 24 inches wide, and the lower about 22 inches (at the head).
Hanging Space
The desire for hanging space led to the removable leaf on the port side berth to make room. Under the side deck there will be a rod to hang things from. Specifically, fenders. This came from our experience with the small boat. Typically (with us at least) as you leave/approach the marina, one person is driving, the other is handling the dock, which includes deploying/recovering fenders. With our small boat, we hang them in the engine room accessed by a hatch in the cockpit. This tends to get in the way of driving. With this design, the fenders can be sent down/pulled from the forward hatch above the head, where they are stored/retrieved from this hanging space just inside the door. Far out of the way of the helmsman.
All Boats Tend to have a "Basement"
And by that I don't mean as in a bilge. But more of a "place-to-store-things-that-don't-normally-have-a-place". V-Berths seem to be ideal because they are so natually cramped you dont want to be in there, and you can't use it for anything else while underway. With our small boat the v-berth always accumulates crap you dont want in the main cabin (luggage, gear, sails, etc.).
Storage First, Sleeping Quarters Second
Generally we anticipate the v-berth to be used for storage 90% of the time. Particularly fenders, gear, sails. If we have overnight guests, the surfaces can be cleared, the leaf for the bunk installed and we now have room for two people.
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