Adding Auxiliary Tank

[DennisG01]

Looks like you're on top of things.

Here's a thought... and I don't think this would really cost all that much at a local welder...

-- Weld a some tabs - say 3 on each of the long sides - so they stick up enough to allow for a hole where you could use a screw to secure the tabs to the stringers (and use blocking in between the tab and the stringer). Make the whole quite a bit bigger than the screw to allow for expansion/contraction/vibration/movement.

Or, along the same idea, get two lengths of aluminum angle iron an use 5200 to glue them to the edges of each of the long side. The do the same thing of screwing to the stringer. You'd have the entire length of the angle iron glued to the top of the tank - I have no doubt that would be a permanent attachment, espeically if you lightly sand the contact points.

For the tank to floor issue you mentioned... maybe it would be easier to address this by modding the FLOOR as opposed to trying to adding things to the bottom of the tank?

Either way, if you haven't already thought of it, make a quick "profile" of the tank shape with a piece of plywood. Basically, trace one end of the tank onto a piece of plywood and cut it out - now you have a perfect representation of the tank bottom's shape and can use that to better fit support needed (whether on the tank or by modding the floor).

 

[Lite Tackle]

Actually, I am procrastinating because it starting raining overnight and it is warm inside and I am enjoying my coffee and watching The Grand Tour. Shame on me.

 

[DennisG01]

I bet Mcmaster Carr (or similar) would have nylon, polyethylene or PVC blocks that you could shape. Any of those would work fine. Smear a good thick layer of 5200 on to the tank, where the blocks will be. That way any water that gets trapped between the block and the tank won't cause corrosion. I think that little step would help ensure longevity as the coating in that area "could" wear away from vibration. But maybe I'm overthinking that one...

 

[DennisG01]

Actually, I am procrastinating because it starting raining overnight and it is warm inside and I am enjoying my coffee and watching The Grand Tour. Shame on me.

Nah, it's a good show! I was worried that when Top Gear got cancelled because Jeremy couldn't control his fists, that that would be it for those guys. Have you seen all of the Top Gears, as well? It was on air for a long, long time.

 

[Lite Tackle]

Dennis, easy to go down the rabbit hole on this issue, right?

 

[DennisG01]

Dennis, easy to go down the rabbit hole on this issue, right?

No question about it! It's like that "while I'm there, I might as well..." And you end up rebuilding half the boat.

 

[Lite Tackle]

No question about it! It's like that "while I'm there, I might as well..." And you end up rebuilding half the boat.

Lol, I resemble that remark.

 

[Ky Grady]

KY, What did you use to make the wedges?

As LT said, those are the original wedges that Grady installed when boat was built back in '04. From what I can tell, my boat came with every option available for 2004, including the auxiliary tank.

Might reach out to Grady customer service and see if you can get the wedges. I went on the factory tour last year but didn't pay attention how the new fuel tanks were secured.

 

[leeccoll]

I just went to Home Depot and purchased a 12' PVC 2 1/2" x 3/4" trim board ("Veranda" they call it-same as Azec boards).
I cut it down and glued/clamped the pieces together with waterproof glue to get the thicknesses I wanted-which was 2 pieces for each spacer.
Then I installed them with 2 1/2" SS lag bolts/w\fender washers on the sides and ends that I purchased from Mcmaster Carr.
Am attaching pics. You can see the spacers on the sides of the tank right before I used the 2 lag bolts/washers on each spacer.
I didn't have the end ones on the bulkheads installed yet in the picture.
I used epoxy to adhere the spacers to the sides of the coffin so they wouldn't fall down before the lag bolts went in.
However, my tank had brackets welded on for the side lag bolts, so you could just epoxy the spacers in after you have the width you need from your dry fit.
In your case LT, I might epoxy the pieces together instead of glue for added strength. They also could run vertically from the floor of the coffin up to the top if it makes the install easier. Just thinking out loud here

 

[Greyduk]

leeccoll , Where did you get your tank? I like the tabs welded on to secure the tank to the stringers.

 

[Greyduk]

I zoomed in and saw Patriot Marine. I like that design. Is you tank the same dimensions as the diagram above? Wondering how tall it is to accommodate the tabs which are used to secure it.

 

[leeccoll]

I zoomed in and saw Patriot Marine. I like that design. Is you tank the same dimensions as the diagram above? Wondering how tall it is to accommodate the tabs which are used to secure it.

Mine is specific for a '87 228G

It is the main tank, but it in the forward section and my aux tank is in the rear behind it if someone wanted that option.
Patriot Marine made width a bit smaller to make the new install easier. That was helpful.
So I think it depends on your hull year, as I figured out on the newer 226/228 models, Grady reversed the locations for the main and aux tanks from what I have.

The dimensions- I am uncertain if they are the same or not. Like LT, I had Grady email me the drawings for my specific hull and year.

Hope that helps you Greyduk

 

[Greyduk]

Thanks. It occurred to me after I posted that of course it was a different year model. Sometimes I seem to be a little slow on the uptake.

 

[leeccoll]

Thanks. It occurred to me after I posted that of course it was a different year model. Sometimes I seem to be a little slow on the uptake.

Not a problem!

 

[Lite Tackle]

Thanks Lee? (I hope that’s your name),

That is a solid install. Weather report from sunny California. Raining cats and dogs! Putting around in garage and came up with this. Had some teak board laying around. 5200 1/4” neoprene to teak to take up space on sides of tank. Surplus starboard across top to hold down tank, toenailed (ss screws) to side bulkheads and voila! See, I told you I would not have to leave casa today.

 

[leeccoll]

Correct, my name is Lee , and thank you.

Looks like you have it figured out. My install configuration had 3- 2x4's running across the top of the tank and under the lip of the deck (that's how Grady did it back in the day) which keeps it sandwiched in place. Between the wood and the tank I also glued strips of neoprene using 5200 on the side facing the wood so there is no wood in contact with the aluminum.

I can also vouch for that same storm, there are 50 mph gusts outside right now in Reno, I just did some shopping and my truck got a free microdermabrasion aka blowing dust that makes you cringe as you hear it impact the car clear coat. You can see the pockets of dirt flying around in the air, and all you can do is take evasive lane changes at times, and take the hits when there is nowhere else to go.

 

[Fishtales]

Nice job. You'll be happy with the capacity and the ride.

 

[Lite Tackle]

Update,

I know I’ll get minus points, but the tank never hit the paint booth. Weather was just too snotty. Found the aux tank sender wire bundle after reaching in bow end deck plate for the main tank. Grady was kind enough to provide the second hole in the port battery box bulkhead for the aux tank 3/8” fuel feed. Fish tape did the rest. No suprises except when I was tightening down the hose clamps and I got a call about the same time I dropped the nut driver into the abyss (beside the tank, not in). Few pics for your enjoyment.

 

[DennisG01]

Good thinking on using the PVC trim board! Not that it matters as I'm sure the glue you used is doing just fine, but since it's PVC, PVC cement could be used, as well. I recently built a "floor" for a skiff (behind the aft seat) out of a large piece of PVC board and PVC glued "chocks" of PVC trim to keep the gas tank and battery for the bilge pump in place.

Tackle, did you happen to heat treat the HDPE before using the 5200? HDPE is so slippery, it's hard to get things to stick to it long term, in my experience. I've had moderate success by torching it, first. Suggestion... Run a long screw or two through each HDPE block and into the teak for added reassurance. Overtime, I really don't think it's that far fetched for the HDPE to separate from the teak.

Painting the tank is great, but you'll be fine for many, many years the way it is - especially since you configured it better than original. I noticed you rotated the worm gear clamps 180* to each other...

How's the tank feel in place? Steady... no rocking?

 

[Lite Tackle]

Good thinking on using the PVC trim board! Not that it matters as I'm sure the glue you used is doing just fine, but since it's PVC, PVC cement could be used, as well. I recently built a "floor" for a skiff (behind the aft seat) out of a large piece of PVC board and PVC glued "chocks" of PVC trim to keep the gas tank and battery for the bilge pump in place.

Tackle, did you happen to heat treat the HDPE before using the 5200? HDPE is so slippery, it's hard to get things to stick to it long term, in my experience. I've had moderate success by torching it, first. Suggestion... Run a long screw or two through each HDPE block and into the teak for added reassurance. Overtime, I really don't think it's that far fetched for the HDPE to separate from the teak.

Painting the tank is great, but you'll be fine for many, many years the way it is - especially since you configured it better than original. I noticed you rotated the worm gear clamps 180* to each other...

How's the tank feel in place? Steady... no rocking?

The HDPE (1/2” Starboard) is only screwed (at angle) into the teak blocks and the bulkheads with 3” SS screws. I did glue the neoprene to the teak blocks with fast cure 5200. Still took too long due to cold temps. I put a small heater on them in the garage over night.