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I want to get the maximum amount of fuel inn the boat with the new tank I don't want to raise the deck could I move the aft tank bulkhead back to make some moore room or any other suggestions im hauling Monday and want to get going on her im also redoing the deck supports because my fuel bladder idea backfired and I broke all the old deck supports on my trip

Tom, (1962 31),
The most I have seen in a 31 without saddle tanks or other spots for fuel was 282 gallons. Ed Murray who passed away back in 2003 had Accurate Metal in Palm Beach Gardens build him an aluminum tank for his 1963 Express Cruiser. The top of the tank was just below the top of the deck supports and he had it extended back about 16'' , just enough room to get to the aft bilge pump. I saw the boat last week at Cracker Boy in Riveria Beach. Billy Hall the new owner had just had the boats deck, cockpit, gunwales, side decks and house sides repainted, really looked nice, he had the Ice Blue hull done a few years ago. He's still running the Crusader 454's FWC that Ed put in back in the 1990's. There is an article on the board about the boat from when the board first started.
I saw in your other post that you broke all the deck supports with the weight of the bladder tank, they must have been ready to go because I've had two giant Bluefin's in my cockpit both of them weighed 1600 pounds. Good luck with you projects.
Pete Fallon

thanks pete I appreciate it that's what im going to do maximize the amount of fuel we hold ya the supports weren't great to begin with not a problem I can fix it

Tom

That much fuel in the stern might be too much for the gas engines. You reach a point of no return. The engines work too hard and burn too much fuel to push the weight. The stern will really squat on you. Try not to go over 250 in the stern tank and then maybe look at doing what JP just did. He put another tank up front where the water tank sits. You can always move the water tank. That will help center the gravity on the boat again.

Look in the Mcmasters Carr site for fiberglass extrunsions you can use for deck supports. No way htose Mahogony supports would have broken if they were not already bad. Check the back support the deck sits on. Bet that is shot also.

You really do not have room to move that one bulkhead behind the engines forward.

I have a 62 Express that came thru with the 160-ish gal tank.
When I replaced due to the Corn Juice in the fuel I went bigger. Slightly higher and longer in the stern so now I carry 222 or so, moved rear bulkhead back a few inches, just enough for a rear bilge Pump.

I should not have gone that much longer...at least not with gas motors. When topped off I run fine...but as tank empties the weight stays to the rear making it a pain to get on plane or travel slow in sloppy weather as she squats. I installed trim tabs, which help alot...but never really needed them before. Once on a good plane, boat levels out and its much better as fuel flows forward more.

Carl wrote: I should not have gone that much longer...at least not with gas motors. When topped off I run fine...but as tank empties the weight stays to the rear making it a pain to get on plane or travel slow in sloppy weather as she squats. I installed trim tabs, which help alot...but never really needed them before. Once on a good plane, boat levels out and its much better as fuel flows forward more.

Carl

I am suprised. Those built from 72 on carried 230 with no problems. You must not have set her far enough forward.

From what I can tell, Bertram increased the tank capacity by changes in how the tank was built and by raising the deck--not moving bulkheads forward or aft. The later boats have less freeboard than the older boats. At least those are the differences between my old 1969 and my newly acquired 1977. I was able to get 230 gallons in the same location on my 1969 as the stock tank without getting too tight on clearances (stringers, deck, bulkheads).

John F. wrote:From what I can tell, Bertram increased the tank capacity by changes in how the tank was built and by raising the deck--not moving bulkheads forward or aft. The later boats have less freeboard than the older boats. At least those are the differences between my old 1969 and my newly acquired 1977. I was able to get 230 gallons in the same location on my 1969 as the stock tank without getting too tight on clearances (stringers, deck, bulkheads).

I think John hit the nail on the head. Think it is also why I had so much issue with taking in so much water as scuppers are pretty low...Deck is lower on the old boats, that I know...how much I do not. I added a couple inches to the top of tank...but mostly I gained the extra fuel by going further to the stern with the tank. I am butted right up to the bulkhead in front of tank.


I think I noticed the difference as I had less fuel before...and fuel sat closer to midship.
Now tank is further back and as I use fuel the front of tank empties out further exaggerating the weight in the stern.

It is not bad...its is just a noticeable difference from what I was used to for 12 years. Boat used to pop up on plane easily at 2600...now I need to push throttle a bit more to get and keep on plane...Kinda like leaving the dock on a shark trip with a few chum buckets, coolers of ice, bait and tackle sitting at the stern. As you get up and go...you notice you are pushing throttles a bit more then usual and riding a bit heavy in the stern.

In retrospect, I would have built deck up another inch or two and been happy with 180-200 gallons.

If I ever go diesel, that will bring weight back to midship...unless its a small 4 banger.

im going a bit taller and longer a healthy amount I have a fifty gallon tank between the motors under the deck so maybe that full will help weight distribution I should be around 240 in the main tank gotta be able to make the canyon runs

I should qualify my answer that when running it really makes little difference as the fuel moves forward again as she levels out at a faster cruise.

1962 31 wrote:im going a bit taller and longer a healthy amount I have a fifty gallon tank between the motors under the deck so maybe that full will help weight distribution I should be around 240 in the main tank gotta be able to make the canyon runs

Tom

There was a point that Bertram actually made a special 50 gallon tank to fit between the engines. Years ago our friend had a 67 that only had the 170 gallons and he bought the 50 gallon tank to fit between the engines right from Bertram. With 230 to 240 in the main tank and 50 in the other, you have more than enough and will probably rock less when that 50 gallon tank is full.

For tanks, try Patriot in Forked River. He has a good reputation.

ya tony im using patriot they are already in process and I should have my old tank out tonight

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