2859 transom/stringer and gas tank project

[sketch96]

Got the tank out of my 2859 and there was definite corrosion issues. Wasn't going to be long before it was going to leak. But what really suprised me was how totally rotten the shelf that the tank sits on was. Push my hand right through it. Bayliner quality control missed the fact that all three Bulkhead pass thru drains from under the tank into the motor compartment were half plugged off with fibreglass from the chopper gun. The bottom drain was tilted about a half inch up so that any water that would run under the tank would never get back out.

Got going on stripping the bad wood out of the transom afterwards. Looks like I have more rot to the starboard side so far.

Stringers are 2x4's sistered together on end, with 2x4 forming the motor mount humps.

[builderdude]

sketch, I see you're wasting no time tearing into your boat. How's the core around the keyhole? Hard to tell from the pic. Looks like the engine stringers solid. I also had a crooked drain tube in bulkhead aft of the tank. Lookin good so far B)

[sketch96]

Core around the keyhole is not too bad turns solid about halfway up. Out to starboard it's not so good. Thinking the trim tab and transducer were leaking pretty good.

Would you leave the stringers and just put new humps back on and refibreglass? They look pretty good. Moisture was built up under the humps only. They were not epoxied to the stringers. Nailed on and fibreglassed over Could epoxy new ones back on after the tank is back in. (Had to remove them to get the tank out or I would have had to cut into the aft bedroom wall to get enough room to lift it over the humps.

May try to pull the stringers out of the shell I left and laminate 3 pieces of 1inch plywood and epoxy bed them into the hull with new mount humps epoxied to that. Not sure yet. They don't look bad as they are.

Going to a fab shop today with the tank to see if they can weld a plate onto the bottom. I can go a bit higher so clearance won't be an issue. Weld on a new bottom to what's there in 1/4". Should last for another 20 years. Cheaper than a whole new tank. Has anyone done this before?

[GearGuts]

I have repaired several fuel tanks over the years most diesel and most steel but none that didn't leak. Reason being is you can't pressure test your repair and let me tell you no welder out there can do a perfect repair in one shot on old contaminated material, especially when the weld interface is overtop a previous weld such as would be the case when doubling up the bottom. I wouldn't do it, I would however look into the industrial epoxy tank coatings available and have your tank soda blasted and epoxied, i have used a product called armor coat before and it is still working well. Your stringers appear from the pictures to be solid but do show signs of moisture, check them out real good and if they are indeed solid all the way through then do your best with some heat and some halogen lights on the bottom of the boat and fans and etc to dry them out as much as possible before you start any glass work. Lots of good posts on here of others doing similar repairs, you should find lots of info and pictures.

[builderdude]

All this work to get that old tank out, replace it with a new one! Epoxy coat the new tank and it'll outlast you, me, and the next 5 guys plus if you ever sell the boat it's going to be a big plus IMO. Also IMO, Yes, if the engine stringers are solid do as GearGuts suggested. Don't get the halogens to close to the bottom of the hull and use fans on the interior. Once it's all dry then epoxy your new towers on.

[fritzman]

Sketch, you are well in to your project, I see the rot so you will need to replace some sections for the stringers after drying the out look for thin Epoxy to poor in, procedure is to get the area- wood warm so it outgases then remove the heat let it sit 15 to 30 minutes the poor epoxy in, the cooling wood will help suck the epoxy. keep the pictures coming . :cheer:

[sketch96]

Gear guts. Are you saying that they could soda blast the exterior of the tank I have now and epoxy coat the outside? Is the epoxy coat thick enough to cover and seal the corroded spots I have and last for ,hopefully, years?

Thanks for the tips guys. This is a first time for me doing all these types of repairs. I've been studying all the forums for this type of fix and learning as much as possible. Fritzman and builder dude were the reason I decided to give it a go. They provided great info on their projects!

[GearGuts]

Yep, If the tank isn't leaking now you can clean and coat it with the product of your choice. Each will have very specific application conditions that must be adhered to, success lies more in that than anything else. I have never used it on a tank before but I have coated a few aluminum boat hulls with west system g-flex epoxy and the stuff adheres very well and is quite thick giving a good film thickness of about a half millimeter and might be cheaper than the industrial tank sealant. If you were to properly clean scuff and top coat with interlux bilge coat I think you would have a pretty good shot at not having any problems as long as you own the boat. Of course the fact always remains that something could go wrong and you could have a leak in the future, but that leak would be identified immediately and repairs executed promptly because you always check your bilge for fumes before you start the boat right ? Right.

[builderdude]

"GearGuts" post=804174 wrote:
Of course the fact always remains that something could go wrong and you could have a leak in the future, but that leak would be identified immediately and repairs executed promptly because you always check your bilge for fumes before you start the boat right ? Right.

So if it does leak again in the future, you get to go through the process of removal and replacement again :woohoo: :huh:

[SomeSailor]

I'd replace the tank. You were close to having a leak and why pass that karma onto the next owner. You could be responsible for the death of a family. New tanks aren't too bad price-wise. Document everything well and you'll increase the resale of your boat.

Don't skimp on a fuel tank replacement. Once the aluminum corrodes, there's no stopping it and it'll likely be another soon. IF.... you insist on repairing it, have a new bottom plate man uafactured and cut off the old entireley, but with good welders demanding good pay, then you'll be a wash if they're doing it right anyhow. Bite the bullet.

[sketch96]

Bit the bullet. Can get a new tank made here where I live. A lot cheaper than heading to Washington to get one from coastline. 1000 to 1200. For me to head down to Washington it would end up around the 2000 mark after exchange, duties, taxes, fuel and hotel.

Makes sense. And nothing to worry about for years to come. Thanks for all the replies!

[sketch96]

I'm making a list of things to do and ran out of paper the list is so long!

Was thinking about the coupler and have decided to replace the input shaft on the leg and the coupler. there are 2 couplers available and one is the long snout steel spline version and the stock aluminum version. Is the steel spline necessary or is this mostly for high hp and work boats? is it overkill for a cruiser like the 2859?

also how do you tell if the rear motor mounts are worn out? do they make a hd version rear mount? It looks like,, from what I can tell, I have the older style non serrated mounts with the double spiral washers. When I look up a new mount kit it comes up with 865330a02. I see some bolt kits have the double spiral washer and others only show a flat washer along with the Fibre washer. What's the reasoning for the different washers?

Started to snow today so stayed in the shop and tore apart the gimbal assembly. Pulled the swivel shaft. Have the stainless one to put in. Looks like this may have been worked on by someone who forgot to put some parts back in. Its missing one of the fibre hinge pin washers and there is no shim under the gimbal ring (hope I described that right) the shim that the ring pulls up against when tightening the large nut on the swivel shaft. Both trim sender/limit switches were not working as the wiring had corroded off of both of them (are these absolutely necessary?). Much work needed there. Lots of parts to order to bring that back to new again!

seems the more I look the more I need to fix/replace.

[fritzman]

Hi Sketch, cant resist chiming in once more, as for the tank I had a local fabricator move the fill and vent, since the tank went forward and it was pressure tested, so yes it can be done look for a welder the runs a Tig welder often and you will have your man. On a separate suggestion wile you have things striped, why don't you lighten the load and get rid of the concrete-under the port side shelf, I pulled out 180 Lbs. I think Dave will chime in since he did this some time back. :cheer:

[builderdude]

Yep, Just moved my house bank over to where I removed the concrete

[builderdude]

"sketch96" post=804235 wrote:
I'm making a list of things to do and ran out of paper the list is so long!

seems the more I look the more I need to fix/replace.

I know the feeling, I still check off one item while adding 3-4 more :blink:

I thInk the aluminum couplers are fine, it's when the alignment goes out for whatever reason the aluminum coupler wears prematurely. With that said I think replacing the rear mounts with the new version is a must do. Me thinks there's a reason mercruiser redesigned those.