[Public-List] Fwd: tanks offset

[crufone at comcast.net]

Thanks for your responses. Here are some additional thoughts. Any further comments appreciated. 

Michael #133 



----- Forwarded Message -----


From: crufone at comcast.net 
To: "Don Campbell" <dk.campbell at sympatico.ca> 
Sent: Monday, October 24, 2011 2:08:58 PM 
Subject: Re: tanks offset 





Hello Don and all other responders, 

  I suspected that the two tanks full would not be different than two extra people aboard one sitting on each gunwale, port and starboard. The reason for two tanks would be just to balance the boat port to starboard. Port would be used for fuel, cuz the carburetor is on the port side and the starboard tank would be used for water cuz the galley is on the starboard side. I was planning on using the original 30 gal water up front for the new holding tank cuz the head is up there. 

Is there some major defect in my thinking of placing the tanks closest to what they are to be used for or what they supply? If I am out to lunch on this please, for gosh sakes set me straight. I never planned to increase fuel capacity to 36 gallons. My original aluminum fuel tank rotted through and my holding tank was an abortion arrangement in the port cockpit locker. 

I needed to replace two tanks and came up with the idea of the two saddle tanks one in each cockpit locker. The previous tanks were located there, albeit not as far out board as where I plan to mount the new ones. I started to wonder about the weight that far oubpard and thought I better ask the group what they have experienced. 

I believe that others have converted the original forward water tank into a holding tank. Does anybody see any major drawbacks to this idea? My boat was not delivered with a holding tank so one has to go back in somewhere. Any other comments about my suggested location of the three tanks is sincerely appreciated. My boat is very stock with absolutely no modifications or built ins. I have ample room to place the tanks where I wish. 

Thank you, 

Michael #133 



----- Forwarded Message -----




From: "Don Campbell" <dk.campbell at sympatico.ca> 
To: crufone at comcast.net 
Sent: Monday, October 24, 2011 10:19:48 AM 
Subject: tanks offset 

Hi Michael: 
     The whole deal is the use of the boat. If you are going to cruise, 
then perhaps consider a trawler. The Alberg was designed as a sailboat 
that was a racer - cruiser and she still fits that bill. There is a 
trade off between weight and range of motoring. Alberg chose about 12 
hours with the A4 which uses about a gallon an hour at hull speed.  If 
you can't get to more than 8 knots, then look at other things first 
before adding fuel tanks would be my advice. Changing props does not 
make much difference to weight but a 2-8 will change speed at the upper 
end. Empty or partly filled tanks collect water, even if they are poly 
rather than metal, and poly tanks have a whole different aspect when it 
comes to static charges and expansion when warm if totally enclosed, - 
which few have mentioned on the list. The jump of static charges from 
poly (tank) to metal (fill hose) can cause serious damage and fires as 
those of us who have had fires aboard from filling Orrigo stoves 
incorrectly know well. 
     As for changes in stability, they are there and they are 
considerable if you add two 18 gallon tanks. The normal SG of liquids is 
about 10 pounds per gallon and that means you are adding about 350   
pounds to the boat every time you fill, all outboard,  probably all aft 
of the center of lateral resistance and probably all above the center of 
gravity.  That si the equivalent of two fairly big crew but no hands and 
dead weight that is not movable ballast , at least forward! If you have 
the tanks joined for even  fuel dispersal, then the one will drain to 
the other on heeling and if you do not, you will be unbalanced too as 
one empties with usage and the other stays full. 
     To me it only makes sense to add extra tankage if you are on a trip 
which prohibits sail,  like the inland route to Florida. And that trip 
can mean changing from gas to diesel with justification based solely on 
fuel considerations.  How many times have you actually run out of fuel 
or that carrying a 5 gallon jerry can did not get you back in?  If you 
go ocean sailing, you will sail not motor, so you can take the motor out 
as Yves Gelinas has done.  I did not think Lake Michigan was that bereft 
of wind or that big  that you could not get to fuel if and when you 
might need it. 
Don