Sunday, September 21, 2008

How much fuel does a "sailboat" need?

Most cruisers, if they are truthful, will admit that the motor-sail a LOT of the time. The ideal image of the boat under full sail, doing 6-7 kts in a flat blue sea is a rare cruising occurrence. Having promised my wife that finally we would have a fabulous down trade-wind sail from Jamaica to Honduras, she was less that impressed when we had no wind for two days and then 35kts for the next two. This brings up the question of how much fuel should a sailboat need? I believe a range of 400NM would be ideal. This would require about 66 hrs of motoring @ 6kts. At 2 gals an hour this would require 130 gals of fuel. I'm sure the purists would use a lot less, but I'm no purist. Once the boat speed drops below 4kts, I find my hand reaching for the ingition key.

As mentioned in the previous post the center tank is a major undertaking and I am convinced that it is probably not worth the time, expense and effort. I will just cap it off for the moment and leave it empty. If some magical coating appears in the future it may be worth revisiting.

The photos below are of the bilge area over the center fuel tank. This was covered by a plywood board glassed into the hull which was used to support the holding tank. On removing this board approx. 4ft of the tank was visible.

The current plan is to replace this platform with an open type support frame that should hold a 30 gal (+/-) Moeller tank. I may also replace the stbd tanks with a Moeller and install one in the original tank space on the port side.

This should give me +100 Gals, in tanks that do not corrode and can be replaced if necessary with a stock product.


robert said...

I agree. Motor-sailing happens more often, especially up here in the PNW.

My philosophy has always been, when seeking to replace/rebuild tank spaces, do so to maximize tank volumes as much as possible, especially for fuel. There will be a time when you will need it.

However, this must be balanced with practicality. The center fuel tank I just ordered for the Westsail, could have been made bigger. While I could have installed it now (throught he cockpit floor), in the future it could never be removed as it will not fit through the companionway. I must anticipate that they may need replacing (hopefully never).

The Incredible Hull said...

Hi Robert

I agree with maximizing space and keeping the retrofit option open. You are in a better position with your center fuel tank. I just don't feel it makes sense for me to cut through the hull or try an in-situ repair, which might fail later.