Gas Tank Replacement - Osprey 245

[seabob4]

The reason I ask is my bilge/ stringers have a finished gel coated surface to them....  nice and smooth like they came out of a mold.

Yes, Bruce, they do.  The 225, on the other hand, has a rough glass finish, sprayed with gel.


When changes were made, I wish I could answer that question...

[Bergertime]

Stopped by the shop today to drop off some more $$$ and some progress is being made.  The new tanks is completely covered in cold tar epoxy from the top side edge to top side edge.  The inside compartment now has been cleaned out and the old and rotten balsa has been removed to make room for the filler to fix the existing deck.  I have also included a simple diagram showing the dimensions of the factory tank and the new one for those of you that are interested.  Have a happy Halloween!

B

[Aswaff400]

we had 4 boats  in the marina get leaking tanks this summer. every one the leak was on the bottom of the tank where the tank rested on the coffin floor or anywhere where water was trapped in the coffin.

[wingtime]

we had 4 boats  in the marina get leaking tanks this summer. every one the leak was on the bottom of the tank where the tank rested on the coffin floor or anywhere where water was trapped in the coffin.

There in lie the key Aaron,  it's ok if the tank gets wet...  but water trapped against the tank is bad bad bad.  That why I like the method of gluing the strips of starboard to the bottom the the tank to allow air to circulate all around the tank.  Of course if the strips come unglued then your back to the same problem.

[flounderpounder225]

thanks Bruce, the dimensions will be a great resource for all of us when the time comes...

[wingtime]

thanks Bruce, the dimensions will be a great resource for all of us when the time comes...

Hopefully not for a LONG time!  

[Bergertime]

The project is moving along and has taken longer that I anticipated.  Mostly due to the rebuild of the existing floors which are being filled with Pour Transom.  Here are some pics of the continued work.

Floor cleaned out with drain tube connecting the front bulkhead with the rear which empties into the bilge:



Tank mounted with foam pour.  Note - The sides are bottom are fully coated with cold tar expoxy:



Foam cut down and sanded:



The rest of the tank glassed in and lines and wire being re-connected:



The new floor (PVC Board) cut to fit existing hole:

[wingtime]

Looking solid.  Question how did they fill the floor with the transom pour?  Through the hole that look like were cut whit a 1.5" hole saw?

[Capt. Bob]

What is under the tank bottom for support?
I'm fuzzy on "transom pour" as it relates to the tank coffin bottom.

I don't believe I have seen a tank mounted (glassed in) with this method.

I've seen them foamed but not glassed over.

[Bergertime]

Wing - Yes, that is how he is doind it.  He said that he thinned the transom pour with resin and then filled it via the holes letting it run aft by raising the front of the boat.  He was/is using PVC board to ensure that each section is full.  He is going to refinish the existing deck by sanding off the factory non-skid and then spray a new one down after the floor is filled glassed and repaired.

Bob - As for glassing in the tank.. I was surprised he wanted to do that but the justification was that the whole tank is completely sealed from any water either by the foam, cold tar epoxy or the glass on the top.  He said, that he built a base for the tank out of PVC board supporting the entire tank and then padded it with rubber. I did not get a chance to get pics of that portion.  I think I am pushing it by stopping by every day during my lunch as it is.  I'm lucky, the shop is less than a mile from my office.  

To be honest I don't think it looks as nice as a new alum. tank but when the deck is overlaid who is gonna see it.  I guess I'd rather it be sealed than pretty... but I am a novice at this for sure. I did question if it was over-engineered for a 15 year old boat.  Thoughts?

[wingtime]

I've never seen a tank foamed and glassed in like that before either.  I think I've heard of them doing that on Classic Mako.  

I guess there are two camps on aluminum fuel tank installs.  

Camp #1: Try to keep them totally dry by sealing them up with coatings, foam. etc. in an effort to keep water from ever reaching the exterior of the tank.  The idea being if water never gets on the tank it will be safe.

Camp#2:  Allow air flow around the tank to allow any water that does get on it to dry and not cause crevice corrosion.  It's OK if water gets on the tank since the open air install will allow for it to dry quickly and not cause corrosion.

If one "camp" is better than the other is anyone's guess.  Neither one is perfect.  Personally I'm from camp #2.

[Capt. Bob]

The rest of the tank glassed in and lines and wire being re-connected:

Might be my eyes but it appears that they glassed over the tank bond/ground post.

[gran398]

Berg, this isn't going to be fun, but we've been chewing on this from the sidelines, and here is the consensus.

The glass over the tank is improper. The tank will sweat condensation... breaking the polyester bond to the aluminum. The two aren't meant to bond anyway.

Once the bond breaks...the tank continues to condense moisture. The glass remains....holding the increasing moisture tight to the tank. Crevice moisture rots aluminum.

This isn't pleasant news.  But she hasn't been decked, so now would be the time to make a change.

Would go with the Pascoe method of aluminum tank install noted recently. Another few hours tops.

Thanks for posting up, and glad you did. Please take this as positive input..and thanks

[Capt. Bob]

If nothing else, expose the tank ground and use it.
Bonding via the fuel sender is not what you want to do.

Good luck.

[seabob4]

I'm just gonna keep my mouth shut on this one...