Oh Boy...This Smell Ain't Good

[Jason2tpa]

I did. But that has nothing to do with the coffin "bed". I'm not sure what you're getting at. From what you wrote, it appeared you were concerned about gluing the tank to the bed/hull.

You're correct, that is a concern. Your suggestion talked about securing tank by using a "few lengths of 1-1/2" PVC angle "iron" secured to the stringers". Scott's suggestion is similar, in that you're using the stringers as an anchor. My concerns about using the stringers as an anchor is detailed in my reply to Scott.

That's what I was trying to get at, sorry for confusion.

[panasonic]

Jason, from looking at the pictures you posted it LOOKS like the floor board above you tank is pretty much parallel to the top of your tank. Once you decide how to secure the tank in place. I like the way Scott's tank is held down. You could take some Precision Board and cut pieces to fit down all around the tank to keep it from shifting side to side, fore and aft. Maybe even bond some pieces to the bottom of the access panel that would just touch the top of tank when the panel is down in place.

Precision board is a water proof high density foam board.It is not effected by solvents either. Meant to replace wood in sign making and is used in boat construction as well. I used it to replace rotten transom and stringers in my boat.

[DennisG01]

See my recent response ^^^ to scott, about the stringers.

I did. But that has nothing to do with the coffin "bed". I'm not sure what you're getting at. From what you wrote, it appeared you were concerned about gluing the tank to the bed/hull.

[Jason2tpa]

Re-read my response above. The PVC strips get 5200'd to the tank, not the boat.

See my recent response ^^^ to scott, about the stringers.

[panasonic]

Ok Jason, here's how my aluminum tank is securred:

Four tabs on each upper end of the tank. The two (looks like 1/4, 20 screws) going thru a small spacer block, then into the stringer.. There is NO foam anywhere to be seen. And obviously, air can get to everywhere(except the bottom I gather).

Above the tank is the deck, I'm photographing thru the ONE access hole. The camera is literally sitting atop the sender unit..


The screws showing from the top secure the two separate seats..

Your boat is even clean under the deck..lol

[DennisG01]

Re: Pascoe method
As i mentioned earlier, 5200 coffin bed to the pvc strips is concerning because of how difficult it would be to extract tank (can you say, come along). But in all reality, it is highly unlikely I would be the owner of this boat 20-30 years from now. So some might say, let the next owner deal with it. What do you say?

Greatly appreciate you taking the time to snap the photo.

Re-read my response above. The PVC strips get 5200'd to the tank, not the boat.

[Jason2tpa]

Ok Jason, here's how my aluminum tank is securred:

Four tabs on each upper end of the tank. The two (looks like 1/4, 20 screws) going thru a small spacer block, then into the stringer.. There is NO foam anywhere to be seen. And obviously, air can get to everywhere(except the bottom I gather).

Above the tank is the deck, I'm photographing thru the ONE access hole. The camera is literally sitting atop the sender unit..


The screws showing from the top secure the two separate seats..

Nice! I like this method. I guess my only concern is getting into the stringer, which are foam filled. 40 year old hull, so I'm doing what I can to prevent the potential for water intrusion.

Re: Pascoe method
As i mentioned earlier, 5200 coffin bed to the pvc strips is concerning because of how difficult it would be to extract tank (can you say, come along). But in all reality, it is highly unlikely I would be the owner of this boat 20-30 years from now. So some might say, let the next owner deal with it. What do you say?

Greatly appreciate you taking the time to snap the photo.

[Jason2tpa]

Ok Jason, here's how my aluminum tank is securred:

Four tabs on each upper end of the tank. The two (looks like 1/4, 20 screws) going thru a small spacer block, then into the stringer.. There is NO foam anywhere to be seen. And obviously, air can get to everywhere(except the bottom I gather).

Above the tank is the deck, I'm photographing thru the ONE access hole. The camera is literally sitting atop the sender unit..


The screws showing from the top secure the two separate seats..

Nice! I like this method. I guess my only concern is getting into the stringer, which are foam filled. 40 year old hull, so I'm doing what I can to prevent the potential for water intrusion.

Re: Pascoe method
As i mentioned earlier, 5200 coffin bed to the pvc strips is concerning because of how difficult it would be to extract tank (can you say, come along). But in all reality, it is highly unlikely I would be the owner of this boat 20-30 years from now. So some might say, let the next owner deal with it. What do you say?

Greatly appreciate you taking the time to snap the photo.

[TownsendsFJR1300]

Ok Jason, here's how my aluminum tank is securred:

Four tabs on each upper end of the tank. The two (looks like 1/4, 20 screws) going thru a small spacer block, then into the stringer.. There is NO foam anywhere to be seen. And obviously, air can get to everywhere(except the bottom I gather).

Above the tank is the deck, I'm photographing thru the ONE access hole. The camera is literally sitting atop the sender unit..


The screws showing from the top secure the two separate seats..

[panasonic]

I think that is pretty much the standard wall thickness for aluminium boats tanks. Folks want cheap and light. A thicker alloy is contrary to what folks want.

What thickness are the wing skins of the aeroplanes that you work on? I came out of general aviation and went to work on air liners. What they called skin we would have called plate.
Wonder what the thickness of an Airbus A380 wing skin is at the wing root? It might not even be aluminium for all I know. More than likely, plastic.

Hard question to answer as it is different everywhere on the wing, fuse, flight controls...

Control surfaces on DHC-8 are 0.020" Rear fuse aft of pressure bulkhead is mostly 0.040"

Wing Planks in near the root can be 0.100" but they taper off as they go out towards the tip.

The pressure fuselage is mostly 0.032" but thicker around openings such as baggage and pax doors, up to 0.060"

Thing to remember that all modern airliner's are build pretty much the same. In the pressure fuse wherever a skin passes over a rib/frame or stringer it has a double layer skin, two pieces bonded together. These tear straps are there to stop any cracks from travelling to far. In between the frames and stringers it is generally just one layer. Wing is build the same, with much heavier frames.

Bigger the airplane the thicker the aluminum to a point. A 747 wont have much thicker fuse skin then our RJ-705. Probably 0.060" But wing skins/frames would be much thicker.

A Cessna 150 is made mostly out of 0.016" maybe some 0.020"

For reference, the top string on a guitar is 0.050" and the bottom string around 0.010"

Big subject.

[Jason2tpa]

For those interested in learning more about poly fuel tanks:

http://www.seastarsolutions.com/wp-c...ochure-web.pdf

[DennisG01]

I believe that foaming a tank is a little bit old-school, and a little bit "the easy way out" by manufacturers. Over time, there is GOING to be moisture accumulation between the foam and the tank. There's no way around it, it's going to happen. That moisture is going to eat away at the tank.

The same holds true for the PVC/rubber strips that you can place on the bottom. They need to be COMPLETELY sealed to the bottom of the tank so no moisture can get in between. Except for right in the middle - maybe a 3"-ish gap (where you don't put the strips) so bilge water can drain out. Using 5200 (or something similar) is a good way to go.

As far as securing it, it actually doesn't take nearly as much as most think. For example, you can use a few lengths of 1-1/2" PVC angle "iron" secured to the stringers and gently resting on the tank. The PVC angle doesn't even have to run the entire length of the tank. These will keep the tank "held down". As far as securing the tank fwd and aft, that can be accomplished through a combination of the fwd and aft bulkheads, along with a few, wide PVC strips for "spacers" (although not entirely necessary, secured with 5200 directly to the tank is probably a good idea). The tank should NOT be stuffed extremely tight into it's coffin. A little bit of wiggle room is good. If you can access the base of the fwd or aft edge of the tank, you can again use PVC angle.

You might want to check with Moeller to see if they have an HDPE tank already in their system that matches up with your space. They supply a lot of tanks to manufacturer's and you might get lucky that happen to have one "on file" from "X" manufacturer. They could supply you with a part number and then you would order it through a supplier/retailer for Moeller.

HDPE holds up very well to ethanol. Fiberglass tanks are the ones that have issues as ethanol eats away at the resins and causes engine issues.

All that being said... please don't ever "drain your bilge" of gasoline that collected in it onto the land or into the water. Yes, it's more work, but you could have gotten some containers (jerry cans) to drain the gas into by being a little ingenious. It ain't the environment's fault... don't pollute, man! OK, good-natured tongue lashing is over.

EDIT: I forgot to mention (and pardon me if it was mentioned above, already)... While I haven't had to personally use them, I've heard plenty of good things about Florida Marine Tanks... in regards to building an aluminum (or stainless) fuel tank for you.

[99yam40]

I know nothing about those probes, but I think Boscoe has talked about a capacitance probe fuel level gauge in the past.
i think it did not have a float, just used the liquid touching the probe.

never mind he already posted on it

[pstephens46]

I have a analog fuel gauge. Anyone have experience using this type of fuel sender, pictured below:





Pictured below is the type of sender I was using in the tank I just pulled. I wasn't very pleased with its accuracy (usually 1/4 off).

My sender is 1/4 off too. In the good direction....makes me feel so relieved when I fill up. Much better than suddenly relieving oneself after filling up...

[boscoe99]

I have a analog fuel gauge. Anyone have experience using this type of fuel sender, pictured below:





Pictured below is the type of sender I was using in the tank I just pulled. I wasn't very pleased with its accuracy (usually 1/4 off).

Millions and millions have experience with that type of sender. Mostly unpleasant. That type of of sender has been around forever. Ancient technology. Referred to as a float on a stick.

For not a lot more money come join us with 20th century technology. Try one of these

CENTROID PRODUCTS - Computerized Tank Display - Electronic Senders - capacitive fuel gauges