Fuel tank replacement

[RickK]

Make sure you grind off all the old core so it's raw glass.  You don't want to try to adhere to old coring.

[clop52]

Sorry its been a few days, i have been working a lot and didnt get the chance to post anything. Rickk, i went back and grined everything to the core, it was worth it. It turned out really good. I had some bubbles after the 1702 dried off, and it wasnt perfect, but i was happy with the results and best of all i learned a lot. I cleaned the top of the lid, added a battery tray and i installed it today. I sealed it with 4200 and tomorrow i will be reinstalling the center console, steering, change the gear oil and she should be ready for sea trials by thursday, or next weekend.  After that, its all cosmetic. I am oiling the teak and adding new hatches to the center console and cleaning/waxing the boat. I had a great time doing it.  Here some pics of my progress, i will end the post early June with some final pics.

[clop52]

[clop52]

[clop52]

Never mind the resin bleed at the bottom.

[CTsalt12]

Hey there folks-reviving an old thread.   I am about to embark on the same project.  same boat, same tank (calling Alloy Metal works shortly). 

CLOP-any chance you still have the dimensions you used for this tank?  Would be a good resource for CAS members. 

I am going aluminum after many issues with my Moeller Poly tank the previous owner installed.

I am thinking I will use modified Pascoe- using factory straps but I will add starboard strap to keep the tank off the bottom of the coffin.

Lastly-I want to talk about coffin sealing methods.  I've had a lot of water intrusion issues, and while it may seem like sealing the coffin is straightforward, there's a lot of methods online. 

My thought process is to lay a thick bead of 4000 UV on the coffin 'ridge' before I lay the coffin cover down.  Then, I will double up and lay a bead in the crack between the deck and the coffin lid.  A handful of my coffin screw holes are a bit damaged and won't hold a screw either...  Not sure how to handle that.  Any thoughts?

[Capt. Bob]

Here are three posts on your original tank dimensions including one from Phil at Alloy:

https://classicaquasport.com/smf/index.php?topic=11420.msg113572#msg113572

https://classicaquasport.com/smf/index.php?topic=11420.msg112278#msg112278

https://classicaquasport.com/smf/index.php?topic=11420.msg112285#msg112285

I used 4000 UV on my coffin cover 11 years ago. Still looks/works well.

I had stripped screw holes also but since I have three hatches/deck plates for access to the tank/battery bay, I thru bolted the cover down. You might fill the holes with epoxy and re-drill.

Just a thought.

Good luck.

[CTsalt12]

Man, that's embarrassing.  I guess I should've done some searching. 

I hope to be done pulling coffin up today.  Most all of these threads have measurements for 170s, and while 170s and 175s are most likely the same sized coffin, I want to be totally sure.

I will fill with epoxy and re-drill.  Good idea Bob. 

Any thoughts on optimal location for fuel fill and vent locations on tank?  Aside from making sure you have an access port.  For instance, does it make most sense to have fill and vent closest to the bow (shortest run).  I am considering re-classing coffin lid as it's gotten a bit 'saggy' so it gives me the opportunity to move the inspection ports around.

[boatnamesue]

Here's the invoice for the aluminum fuel tank I had built for my '76 170.  Fabricator did a great job and quick turnaround time, located in Venice FL.  Can't beat the price either.  Tank specs are listed on the invoice.