Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 15-09-2011, 00:18   #1
Registered User

Join Date: Jan 2011
Posts: 31
Upsize Water and Fuel Tanks

I have a Cal 34 with a 10,000# displacement. I am planning to upsize the fresh water and diesel fuel tanks from the present 25 gal water and 28 gal fuel.

What are the 'Rules of Thumb' for water and fuel tank sizes for 2 people and 2 month cruises?

Thanks - Charles

micheck is offline   Reply With Quote
Old 15-09-2011, 00:41   #2
Registered User
bangkaboat's Avatar

Join Date: Feb 2009
Location: Sihanoukville, Cambodia
Boat: looking
Posts: 593
Images: 3
Re: Upsize water and fuel tanks

Weight & placement are the big issue, of course. If you can afford a watermaker, I'd suggest going that way. I'm doubling the capacity on my Cal 2-30 & have moved my house batts forward and my anchors/chain aft & lower to compensate for the added weight of the tanks. You can never have too much water, right? If you went for 1 gallon/day you'd need 60gallons & would have no reserve. I managed to accommodate 80 gallons on my old 3-30 & that seemed like much too much when my brother or friend & I sailed, but not with my wife & I. But my wife smelled better! Fuel will really depend on how much you rely on your engine, some use it much more than others.

bangkaboat is offline   Reply With Quote
Old 15-09-2011, 05:33   #3
Senior Cruiser
DeepFrz's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 7,061
Re: Upsize water and fuel tanks

I think a lot depends on where you are cruising. Don't forget to increase the size of your holding tank as well.
DeepFrz is online now   Reply With Quote
Old 15-09-2011, 07:02   #4
Registered User
denverd0n's Avatar

Join Date: Jun 2008
Location: Tampa, FL
Posts: 3,475
Images: 6
Re: Upsize water and fuel tanks

Water weighs about 8-1/3 pounds per gallon. Gas weighs about 6 pounds per gallon. Every pound you add changes your boats sailing characteristics, weighs it down, and slows it down. And the Cal-34, at 9,500 lbs. displacement, is designed as a pretty light-weight 34 footer, so extra weight is going to affect it more than it would a boat designed with a relatively high D/L ratio.

As such, I personally would not add more than about 5% to the boat's displacement. That would be 475 lbs, and still allows you to add something like 20 gallons of gas and 40 gallons of water.

Now you have to consider where you are adding this weight. Obviously you're creating a problem if it is all on one side, so you have to balance it port and starboard to avoid listing. You need to get it down as low as possible, though the Cal-34 has a ballast ratio of almost 40%, so it won't be the end of the world if the weight is not right down in the bilge.

The general rule of thumb for water is 1 gallon per person, per day. Are you really thinking of spending two months away from facilities where you can refill? Then you need 120 gallons, which is really too much for this boat. If you are going to be doing a more typical cruise, where you are usually able to refill every 2-3 weeks or so, then 60 gallons becomes plenty. If you are cruising through the Caribbean, where you can fill up every few days then the 25 gallons you have is enough. In fact, that's exactly what a boat like the Cal-34 was designed for.

As for gas, only you can decide how much and how often you will run the engine. Some cruisers do it all the time. Some hardly ever. I'm one of those "the boat was made for sailing" types. Some people, you wonder why they didn't just buy a powerboat to begin with. I used to dock next to a guy who--quite literally--ran his engine all the time, even when he had the sails up (which, frankly, I think he spent more time motoring with his sails down than he did with his sails up). I'm quite sure that he burned as much diesel in the course of one day of day-sailing as I would burn during a 2-week cruise.
denverd0n is offline   Reply With Quote
Old 15-09-2011, 15:21   #5
Senior Cruiser

Cruisers Forum Supporter

Join Date: Nov 2005
Location: Tasmania
Boat: VandeStadt IOR 40' - Insatiable
Posts: 2,316
Images: 91
Re: Upsize Water and Fuel Tanks

You might want to consider increasing the fuel capacity, leave the water capacity as it is and install a small watermaker.
Weyalan is offline   Reply With Quote

fuel, fuel tank, water

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
The Perfect 30' Yacht Design ? TheCruisinKitty Monohull Sailboats 55 21-01-2014 17:24
Fuel from Salt Water Capt. lulz Electrical: Batteries, Generators & Solar 3 25-08-2011 19:19
Fuel Tanks casual Construction, Maintenance & Refit 8 22-08-2011 10:32
Converting Water to Fuel Don1500 Liveaboard's Forum 12 05-08-2011 18:55
For Sale: Gemini 105Mc 2008 Therapy Classifieds Archive 17 12-07-2011 18:33

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 14:59.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.