T&T: Heeling and fuel tank crossover

[Bob McLeran]

We've now had two trawlers, both with a fuel tank on each side of the 
boat connected by a crossover line. The first trawler was a 35 footer 
weighing about 12 tons and carried 200 gallons (1400 pounds) of diesel; 
the current trawler is 41 feet weighing 20 tons and carries 400 gallons 
of diesel (2800 pounds).  The crossover lines were/are always open all 
of the time. The first trawler listed a little to port all of the time 
because of the weight of the refrigerator and battery banks on that side 
of the engine room; this trawler lists a little to port when I fill the 
water tanks (160 gallons - 1200 pounds) because they're located to the 
left of the center line, but are balanced to some degree by the 1300 amp 
battery bank on the starboard side of the engine room and about 200 
pounds of chain on the starboard side of the lazarette. As the water 
tanks empty, the boat levels and then will list very slightly to 
starboard when the tanks are empty. Both boats went/go for months 
without any change in angle of heel.

I've never had any reason to think that fuel flowed through the 
crossover line from one tank to the other as a result of the slight list 
caused by obvious other factors; if it did, it didn't result in any 
change in the angle of heel.

I'd be interested in seeing some scientific proof that fuel actually 
causes a list to increase via an open crossover line; the hypothesis 
many posters present is simply speculation without scientific proof, but 
then, so is my anti-listing hypothesis, but at least it's based on 
experience with two different boats.

<><><><><><><><><><><><>Mozilla Thunderbird<><><><><><><><><><>
Bob McLeran and Judy Young               Manatee Cove Marina
MV Sanderling                            Patrick Air Force Base
DeFever 41 Trawler                       Melbourne, Florida     
Blog: http://sanderlingcruise2009.blogspot.com/
Pictures: http://public.fotki.com/rmcleran/