bertram31.com

OK, well yesterday i started pulling up my deck, got all the vinyl up and the middle section out, i looked in the tank through the sender hole with a flash light and mirror and saw NO damage, but as far as i know it has only had one tank of ethanol in it. And for being 40 years old, the deck was pretty solid except in a few places, so was the deck supports, i just wonder if it has ever been replaced, but my tank doesn't have any lifting eyes, is that normal for a factory tank? and the back of the tank has a sheet of ply wood tabbed in with gray epoxy or resin??

So far, all sounds right. None of the tanks have lifting eyes.

10-4 i thought i read that some did.

My other question is... is 1/4" aluminum required on tanks, or can you go with 3/16". i mean 1/4" is pretty darn thick
also any body know a good welder in the texas area. so far my best price on a 231gal tank is from RDS in florida, and the guy i know here wants 15.00 bucks a gallon

My 72 FBC has a lifting eye on the rear of the tank, on the aft side, not on the top and its glass. Don't think I've ever looked at the front of the tank for one. The plywood is stock. Bertram started using the 222 gallon tank in 1972. Look on the top of the tank, aft end, for a slip of paper glassed into the top of the tank with the manufacturing data typed on it. Mine was real hard to find, took a lot of scrubbing decades of dirt off to see.

UV

Bertram actually made three fuel tank designs for the B31.

When they were playing with a larger tank in '71, there were a few, maybe not not more than a couple, that were fitted with a 200 gallon tank that had a recessed pocket for the fill pipe.

The 200 gallon was a calculated volume, but because of the recessed pocket there was no way to actually fill the tank to full capacity... Realizing their mistake, the 223 gallon tank was produced. I never saw one of these until I started working on Hancock's B31; it's a 1971 with the pocketed tank...



The solution for Pat's tank was to glass in an aditional manifold, mounted to the top of the tank and cap off the pocketed fill...



The other two tank designs can be readily identified by the general construction. The 173 gallon tank, ('61-'71), has a flange mounted top. The 223 gallon, ('72-'86), has a "shoe box" top. The 223 gallon tanks all have a fiberglass lifting eye at each end.

Ya i have the 170 gal tank. cant wait to try and bust that foam loose!! i am so excited about that.
Capt. when are you going to publish a service manual/DYI guide to the 31?? i know i would buy it!! That way when ever guys like me start a project we can keep the book right by our sides, maybe a 31 bertram guide for dummies haha

Capt. when are you going to publish a service manual/DYI guide to the 31?

Well, I've given that question a lot of thought over the past 10 years, and the day may come.... Stranger things have happened.

I hope you make it quick, before I go and screw something up! haha

I went 3/16" aluminum...they thought it was overkill.
I also gave a coat of Coal Tar Epoxy, Nasty Stuff.

My buddies tank was made from 12Ga Alum, about 150gal and was Epoxy coated. That is what was recommended to me, but I opted for 3/16" and hoped to get a few more years out of it.

capt pat,
on a new deck is it better to laminate two pieces of core material like two pieces of 3/8 or just use a solid piece of 3/4" or whatever thickness i go with. or just say solid glass

sim, i think 3/16" on a 150gal tank is ok, but i have been told on a bigger tank, like 250gals you need thicker. I dont know

If I were fabricate a deck, it'd be with 3/4 Coosa board. I'd never use plywood. Too heavy, too much chance of water intrusion...

10-4,
I am looking into finding some here locally I am pretty sure composites one has it, i just didn't know if its better to laminate 2 sheets to make the 3/4" or just one solid sheet.

The 3/4" Coosa Board is already a factory lamination so there's no need to to duplicate their efforts. Composites One does carry the material, although I'm not sure if they carry the Coosa or Penske brand. They're both essentially the same product. If you're looking for more rigidity from the material, add a heavy glass layer to the underside of the deck. Two layers of 1208 biaxle fabric, on the tension, (under), side would stiffen it up by almost twice. Add a couple of layers of 1 1/2 oz chopped strand matt to the compression, (top), side and gain another 200% of rigidity, plus better abrasion resistance.

Question,

Aren't the gallons marked on the label the usable amount. For my 75, the tag always said 220 gallons.

Tony - on my 72 FBC the tank tag says 230 gallons along with the test pressure, etc. I was always under the impression that the "usuable" was 222....but on a two day trip offshore I came in on diesel fumes and put 226 in the tank, and both engines and the genset were still running.

I'm not sure that Bertram actually built the tanks, seems someone told me they farmed them out, like they did with a lot of parts to Glass Tech. Does anyone know for sure?

UV

Bertram actually built all of the B31s from start to finish, nothing farmed out. Norberto Ferretti was the first to move Bertram from a vertical company to a horizontal one. Now all components, other than the main hull parts are farmed out to speciality houses.

Glasstech was an out growth business that started after the B31 was finally taken off line. Most of the original Cuban workers who built the B31s went to work for Glasstech.

Bertram never made a dime of profit from the B31... Source: Don Jones, VP Bertram Yachts

It is just really strange that mine said 220 gallons and it did also show the pressure test amount. The tag was not glassed in and after beign exposed to the weather after the repower it has worn off. Unfortunatelly when they launched her after the repower I was not there. They put about 200 gallons in her but actually did not top her all the way before the sea trial. They said they figured about 200 gallons seamed right. So I am not sure if she would have taken 220 or 230.

Its just strange that they would use different labels. I was really hoping to figure that out when we filled her up when she went in the water. Well I guess this is one that will remain a mystery for a little longer.