Started cutting out fuel tanks.

Post your photos of Repairs and/or Outfitting projects

Started cutting out fuel tanks.

Postby Imaginethat » Sat Nov 09, 2019 10:19 pm

Port tank developed a leak if filled with more than 7" of fuel :cry:
I knew I'd need to replace the tanks when I bought the boat a year and a half ago, so no big surprise, just hard to find the time and motivation to get started... but today was the day!
Actually, I started preparation last week and removed the 7.5kw Onan generator

Temporary posts were put between the stringers and the floor timbers under the hoist (4 places)
2x6 (full dimension) 12ft planks and 3/4" conduit rollers with the generator on a thin piece of plywood allowed it to JUST fit out the aft companionway.

I then pumped the tank empty through a Racor 1000 into to the other tank
1974 GB 36 Classic #467 "Imagine That"
Bellingham, WA
View user's profile Send private message Send e-mail
You do not have the required permissions to view the files attached to this post.
Imaginethat
Posts: 28
Joined: Mon Mar 26, 2018 9:24 am

Re: Started cutting out fuel tanks.

Postby Imaginethat » Sat Nov 09, 2019 10:23 pm

Getting ready
1974 GB 36 Classic #467 "Imagine That"
Bellingham, WA
View user's profile Send private message Send e-mail
You do not have the required permissions to view the files attached to this post.
Imaginethat
Posts: 28
Joined: Mon Mar 26, 2018 9:24 am

Re: Started cutting out fuel tanks.

Postby Imaginethat » Sat Nov 09, 2019 10:24 pm

I thought I'd try a Bosch 10ga nibbler rather than sawsall and grinder like most people have used. Gotta say it was definitely the way to go! No mess, no fire, and really fast (relative to the other two methods). A bit tricky to get past the baffles. Fortunately their notched corners made it possible. I cut the inboard side into 3 sections and was able to lever each back and forth to break the welds where the baffles were attached.
1974 GB 36 Classic #467 "Imagine That"
Bellingham, WA
View user's profile Send private message Send e-mail
You do not have the required permissions to view the files attached to this post.
Imaginethat
Posts: 28
Joined: Mon Mar 26, 2018 9:24 am

Re: Started cutting out fuel tanks.

Postby Imaginethat » Sat Nov 09, 2019 10:25 pm

Next was cleaning up the 1/2 inch or so of schmutz on the bottom of the tank. A 6" putty knife and a 5 gal bucket with a garbage bag liner made it not too bad. Soaked up the remaining fuel and water with bilge soaks and paper towels, then got to work cutting out the baffles.
1974 GB 36 Classic #467 "Imagine That"
Bellingham, WA
View user's profile Send private message Send e-mail
You do not have the required permissions to view the files attached to this post.
Imaginethat
Posts: 28
Joined: Mon Mar 26, 2018 9:24 am

Re: Started cutting out fuel tanks.

Postby Imaginethat » Sat Nov 09, 2019 10:26 pm

I drilled a hole in the center of each of the (3) fore-aft baffles to start the nibbler, then cut diagonally to each corner where there was just enough room to exit the nibbler (it was less smooth than I'm making it sound here... got the nibbler stuck a number of times). Once quartered, I was able to bend each piece back and forth to break the welds... all except 2 sections - the inside vertical piece of both outside chambers was welded both sides... I gave up trying to break them off, nibbled a notch and bent tips to make room for the nibbler to pass while cutting the two side to side baffles top and bottom.

I finished the evening pretty tired. About 8 hours straight, not including the generator...
1974 GB 36 Classic #467 "Imagine That"
Bellingham, WA
View user's profile Send private message Send e-mail
You do not have the required permissions to view the files attached to this post.
Imaginethat
Posts: 28
Joined: Mon Mar 26, 2018 9:24 am

Re: Started cutting out fuel tanks.

Postby Imaginethat » Sat Nov 09, 2019 10:27 pm

Next I'll use an angle grinder to nip the outboard welds on the baffles to remove them, then sawsall or grind out a section in the inboard and forward and top corners of the tank to start the nibbler. I figure I can nibble the top in half, inboard-to-outboard between the floor timbers, then sawsall or nibble down the outboard side and also the bottom (careful to not cut exhaust or tank support). Then cut the forward wall of the tank mid-height and across the outboard wall so the forward top and bottom quarters come loose. Once they're removed, I should be able to slide the aft half of the tank forward, giving me room between the tank and bulkhead to cut it in half similarly.
1974 GB 36 Classic #467 "Imagine That"
Bellingham, WA
View user's profile Send private message Send e-mail
Imaginethat
Posts: 28
Joined: Mon Mar 26, 2018 9:24 am

Re: Started cutting out fuel tanks.

Postby StevenD » Sun Nov 10, 2019 11:01 am

Been there, still doing that! Try to save the profile of the bottom of the tank as a template for the new. The nibbler sounds like a less stressful way of attacking these bears. May try one on my port tank (if I ever finish the stb.) Nice job of finessing the genset out!
Steve D
M/V Kumatage
Hobe Sound, Fl.
GB 46 CL
View user's profile Send private message Send e-mail
User avatar
StevenD
Posts: 42
Joined: Mon Mar 19, 2018 10:38 am
Location: Hobe Sound Fl

Re: Started cutting out fuel tanks.

Postby StevenD » Sun Nov 10, 2019 11:13 am

BTW, let the dock-master know the fuel is all on one side causing the list. It will avoid that late night urgent phone call that your boat is sinking.
Steve D
M/V Kumatage
Hobe Sound, Fl.
GB 46 CL
View user's profile Send private message Send e-mail
User avatar
StevenD
Posts: 42
Joined: Mon Mar 19, 2018 10:38 am
Location: Hobe Sound Fl

Re: Started cutting out fuel tanks.

Postby Imaginethat » Sun Nov 10, 2019 10:09 pm

I only had about 50 gal fuel, so didn't list noticably. (it did help the fuel get to the fitting I was pumping out of tho!)

Today I pumped 30 gallons through the Racor into jerry cans in preparation of tackling the second tank removal.

I finished removing the starboard tank but cutting a panel out of the outboard side with the nibbler, then cutting the top into two sections and removing. This lightened the remaining L shaped piece to lift it up and slide it forward so I could get the nibbler into the aft wall.

I finally found the leak! While drilling a hole to start the nibbler, a chunk about the size of a quarter fell out. Over the years a leaky deck fill dribbled on top of the tank , ran aft and down between the tank aft bulkhead. If only they'd left 1/2" or so gap when installing the tanks!

This was about 5 hours work including hauling all the pieces and the 30 gal of fuel off the boat, into a dock cart, up the ramp, into the truck, home and out of the truck. 2 days of working crouched in a 3ft tall space, lifting heavy power tools and hauling out all the pieces of tank have me feeling like I'm getting old!

I used a diamond blade on the angle grinder to cut the welds in the remaining baffles. It really cuts down on the smoke and grit compared to abrasive cutting wheels. I had bought a couple different brand 5 packs plus a Diablo carbide blade thinking I'd do a comparison.. The Craftsman 18 tip bimetal blade held up surprisingly well, and is still in servicable shape. I might use the sawsall more on the other tank, but the nibbler was nice not having to worry about accidentally cutting something on the backside.

Two thing I figured out: always remove the holesaw from the arbor when drilling the pilot hole (it took a couple broken center drills to get this into my head!), and if you drill at a bit of an angle with the holesaw it cuts through much faster.

next up - cleaning the space...
1974 GB 36 Classic #467 "Imagine That"
Bellingham, WA
View user's profile Send private message Send e-mail
You do not have the required permissions to view the files attached to this post.
Imaginethat
Posts: 28
Joined: Mon Mar 26, 2018 9:24 am

Re: Started cutting out fuel tanks.

Postby Berger » Sun Nov 10, 2019 11:52 pm

Really nice description of the process.
View user's profile Send private message Send e-mail
Berger
Posts: 167
Joined: Mon Aug 21, 2017 6:02 pm
Location: San Francisco
Supporting Member

Re: Started cutting out fuel tanks.

Postby Charlie0 » Mon Nov 11, 2019 5:30 am

Thanks for this. I am hoping that I will always be a spectator but I think not.
Charlie O
Grand Banks 36
Hull 715
View user's profile Send private message Send e-mail
Charlie0
Posts: 171
Joined: Fri Sep 09, 2016 11:11 am
Location: New England / Narragansett Bay

Re: Started cutting out fuel tanks.

Postby FrugalWife » Mon Nov 11, 2019 1:24 pm

Just did the same this past May. Nasty job but the second tank took a couple hours less time due to less thinking about cutting strategy. I used a sawzall and 20 blades. The first tank took 7 hours to cut, remove all the pieces, and cleanup the mess. I used a shop vac to clean up the metal “sawdust”. The second tank only took a little over 5 hours to do the same. It’s the cycle of learning thing that gives you the tank 2 time advantage.

First of all I am getting old (63) and have had so far 3 back surgeries so, yup, it’s hard work and well deserving of some liquid painkiller at the end of the day!

The next question is what’s going back in?
View user's profile Send private message Send e-mail
User avatar
FrugalWife
Posts: 490
Joined: Sat Dec 03, 2005 2:00 am
Location: Kennebunkport, ME

Re: Started cutting out fuel tanks.

Postby StevenD » Tue Nov 12, 2019 9:15 am

These are the mock-ups of the tanks that are going in Kumtage.The aft two are 17" wide (the max to go thru the cabin door), go in horizontally then stand upright while the fwd tank is 15" wide and slides in vertically behind the engine/in front of the aft water tank. She'll carry about 318 gal. to stb. The first real tank goes in today.
Steve D
M/V Kumatage
Hobe Sound, Fl.
GB 46 CL
View user's profile Send private message Send e-mail
You do not have the required permissions to view the files attached to this post.
User avatar
StevenD
Posts: 42
Joined: Mon Mar 19, 2018 10:38 am
Location: Hobe Sound Fl

Re: Started cutting out fuel tanks.

Postby Berger » Tue Nov 12, 2019 12:03 pm

Hey Steve Not sure if you know this but American tank in Ca. has built so many replacement tanks that they already have them templated. Mine were replaced by the PO and are stacked on top of each other.
View user's profile Send private message Send e-mail
Berger
Posts: 167
Joined: Mon Aug 21, 2017 6:02 pm
Location: San Francisco
Supporting Member

Re: Started cutting out fuel tanks.

Postby Charlie0 » Tue Nov 12, 2019 4:02 pm

318 gallons starboard side only???? Another 318 on port?
Charlie O
Grand Banks 36
Hull 715
View user's profile Send private message Send e-mail
Charlie0
Posts: 171
Joined: Fri Sep 09, 2016 11:11 am
Location: New England / Narragansett Bay


Who is online

Users browsing this forum: No registered users and 2 guests