Oh Boy...This Smell Ain't Good

[DennisG01]

With just my two pointy fingers yet!

EDIT: I tried to just respond with just the smilie face thingy, but the forum said I had to use at least 10 characters. So I edited by adding these two statements... which is now much longer than 10 characters...

[panasonic]

Possibly a dumb question, but oh well here goes. The 4 tabs that would be welded to AL tank...do these tabs need also be AL or could they also be SS? Same applies to the screws. Not sure if SS has an "alergic" reaction to AL. Is there a metallurgist on forum

It's a catch 22 situation
The aluminum tabs on the tank need to bolted/screwed to boat. What to use? Stainless bolts or screws. But these are dissimilar metals and galvanic corrosion will occur, with the aluminum on the losing end. OK use regular zinc plated bolts, not so dissimilar but the old zinc plated bolt will rust away in quick order on a boat. So back to stainless.

So like Scott said you can isolate one from the other with a plastic washer and it should be fine. I use sealant on the washer under the head or nut to prevent direct contact between the stainless and aluminum.

See chart.

[TownsendsFJR1300]

The tabs should be made out of aluminum, but the hardware will be SS. It should be just fine. If you want to take an extra precaution, you can use a nylon washer between the screw head and the aluminum tab. EDIT: Looks like Scott typed his response faster than me!

With just my two pointy fingers yet!

[DennisG01]

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.

Oh, OK. I see what you're saying, now.

OK, here's a way you could go if you're unsure how thick the coffin sides are and whether or not they will support being screwed into. But, one thing to note..... the primary strength of stringers comes from the vertical section of the fiberglass. Even with a wood cored stringer, the fiberglass is the main component, not the wood....... Have the tank built slightly narrower (maybe an inch to an inch and a half) than the coffin sides. This will allow you to build out the wall of the "stringer" with another 1/2" of fiberglass in the area that will receive the tab screws. This will now be PLENTY strong in this area. And because the tank is still narrower than the built-up areas, it can still easily drop in, or out. If there ends up being a gap between the tab and the built-up area, that's easily remedied with a couple washers (or even a nut) as "spacers".

The foam board referenced, while solid stuff, should not be placed against the tank (unless it's epoxied FULLY to the tank). If it is, we're basically back to the same issues we can have with the pourable/expandable foam... trapping moisture against the tank. Ideally, we want AIR SPACE around the tank (including the bottom) to help it last as long as possible.

The tabs should be made out of aluminum, but the hardware will be SS. It should be just fine. If you want to take an extra precaution, you can use a nylon washer between the screw head and the aluminum tab. EDIT: Looks like Scott typed his response faster than me!

[TownsendsFJR1300]

Possibly a dumb question, but oh well here goes. The 4 tabs that would be welded to AL tank...do these tabs need also be AL or could they also be SS? Same applies to the screws. Not sure if SS has an "alergic" reaction to AL. Is there a metallurgist on forum

Don't need a metallurgist for this one.....

You can't weld aluminum to SS so those tabs have to be aluminum..

I'm sure the screws are SS with flat SS washers spreading some of the load.
If they weren't, they'd be rusty after 19 years on the head.

Mixing the two there isn't an issue. If you want to make/put a plastic washer between the aluminum and SS bolt you can.

The screws would simply be slipping thru the tabs and "threaded" into the wood/anchor/what ever you use as a spacer...

Mine doesn't appear to have anything.. You likely won't be touching that tank for another 20 years...

[pstephens46]

The "harder" metal wins. I would use thick AL if available. If touching tank.
Sometimes you have no choice. Fasteners, etc. bolts screws

[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..

Possibly a dumb question, but oh well here goes. The 4 tabs that would be welded to AL tank...do these tabs need also be AL or could they also be SS? Same applies to the screws. Not sure if SS has an "alergic" reaction to AL. Is there a metallurgist on forum

[panasonic]

Precision Board Plus HDU - Coastal Enterprises

[pstephens46]

I believe that precision foam board is called a few different names by manufacturers. If it is what I think, they build modern transoms with it. Drill holes and mount big motors. With washers, it doesn't compress.
Brutally strong. So no wood needed..... I don't build boats. Wish I knew how. Like those guys that live around Rodbolt and build those killer 70 ft Carolina boats. They also told the stuff doesn't absorb water. So no freezing damage...of course some of you have no worries about that!

[Jason2tpa]

I would think think the stringers have to have wood in the middle...

How would you make a stringer of foam, then Fiberglas over it, just doesn't make sense..

Foam filled fiberglass. The pictures below will help you visualize. First pic the foam has been extracted from the fiber construct. 2nd pic shows the fiber construct filled with foam, ready for deck installation. These pics are not of my hull, they are of the same model/year hull ('76). Fuel coffin is the forward compartment, bilge aft.

This innovative stringer construction is one of the primary reasons AQ hull's last as long as they do. All other hull manufactures in the late 60's & 70's used wood and/or fiber stringer systems. How many 1970s Ranger hulls do you see around these days?



[IMG][/IMG]

[TownsendsFJR1300]

it's a hard foam and it's meant to be glassed over, resin does not melt it.

I just meant he could use pieces of this material as spacers AFTER he gets the tank secured in. To make sure it doses not shift around.

I made stringers from it and glassed them in, very stiff and strong and will never rot like wood.

Interesting!

Well, if it's strong enough to be a stringer, epoxying pieces to it (the bigger the better-more surface area), would be the way to go...

[panasonic]

it's a hard foam and it's meant to be glassed over, resin does not melt it.

I just meant he could use pieces of this material as spacers AFTER he gets the tank secured in. To make sure it doses not shift around.

I made stringers from it and glassed them in, very stiff and strong and will never rot like wood.

[TownsendsFJR1300]

I would think think the stringers have to have wood in the middle...

How would you make a stringer of foam, then Fiberglas over it, just doesn't make sense..

In any event, IMO, have the tank built your yours, (print out my pic for the welder) and as shown it'll fit slightly loosly in the hull.

Now custom cut some of that material (posted above) to take up the little bit of extra space between the tank and stringer (each side). Epoxy that piece to the stringers and bolt the tank to those.

A for the bottom, dunno what's at the bottom.

BTW, thought my tank was a 60 gallon. Per the original sales brochure, it's 50 gallons..

Re my tank, that's the first time I've seen how it's mounted. As noted earlier, I did wipe off a wet , saw dust like material years ago. That black color on the top of the tank was my acrylic paint I applied years ago(looking thru a mirror-working backwards-PIA) to stop the couple of white spots. Thought I might find some "dust" under there today that needed a wipe down, nope. That hasn't been opened up in at least 4 years... I kinda dreaded having what your going thru right now but I guess that's highly un-likely (thanks Jason, really)

[Jason2tpa]

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.

I too like scott's method. I have my concerns about using the stringers as an anchor, only because my hull is 40 years old. I'm a member on a classic aquasport forum. I started a new thread voicing this concern. I'm hoping to hear from a few members who i know have a lot of experience with classic AQs. If they think screwing into adjacent stringers is no problem then scott's method is what i'll do.

I got 8 quotes on a custom made AL tank from 8 different sources. The highest was $515, majority in the $430-$480 range. Low quote is $355, which is the one I'm going with. Not because it's the cheapest, though this works out nice. Fabricator named Tony, Sunrise Marine Tanks in Venice, FL. He had been recommended by 3 different sources. Good price and good referrals, no need to shop around anymore.

[Jason2tpa]

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.

I too like scott's method. I have my concerns about using the stringers as an anchor, only because my hull is 40 years old. I'm a member on a classic aquasport forum. I started a new thread voicing this concern. I'm hoping to hear from a few members who i know have a lot of experience with classic AQs. If they think screwing into adjacent stringers is no problem then scott's method is what i'll do.

I got 8 quotes on a custom made AL tank from 8 different sources. The highest was $515, majority in the $430-$480 range. Low quote is $355, which is the one I'm going with. Not because it's the cheapest, though this works out nice. Fabricator named Tony, Sunrise Marine Tanks in Venice, FL. He had been recommended by 3 different sources. Good price and good referrals, no need to shop around anymore.