Size of fuel vs water tanks

[JonnyBoats]

Traditionally crusing sailboats have fresh water tanks that are far larger than the fuel tanks. Most of the classic sailboats were designed before watermakers became common.

From what I have been told, a watermaker can make something like 20 gallons of water from one gallon of diesel.

Clearly one needs to carry some water since a watermaker can break. Does it make sense to setup a crusing sailboat with more diesel than water capicity?

[Tim]

...a watermaker can make something like 20 gallons of water from one gallon of diesel.

Wow, that's quite a trick. Now if only you could reverse that process.

[bcooke]

Wow, that is an interesting way of looking at the capacity question.

I would hate to run the engine just to make water but if you use the motor quite often anyway then I could see where it could make sense.

How long away from water re-supply sources do you plan on being?

If you are going to rely heavily on the water maker then having a spare might make sense.

-Britton

[Hirilondë]

I love that they are called water makers. Like you really combine hydrogen and oxygen, or use alchemy or something. Too bad it isn't alchemy, or Tim could do the reverse and refuel at sea.

Our mechanics install quite a few "water makers". But usually only on very large boats and those that do blue water sailing. I don't know that any of them analyze the ratio of the two types of tanks. On smaller boats this might be something to consider though.

I would still want to assure I had enough water at sea to survive should the water maker break down. Electrical/mechanical systems in a salt water environment do occasionally malfunction. I recall reading somewhere of a boat doing one of the 'round the world races running into serious trouble due to relying on a water maker to allow them to avoid the weight of actually carrying the stuff in tanks.