Update on fuel tank change

[Kommy000]

Thought I would share the progress.
I posted while back about having fuel or oil in my bielge and figuring out it was diesel.
I finally was able to remove the panel between engine and tank and side panel too. Panel between engine and tank was soaked with diesel.
I looked at the hoses and they all dry and I didn't see any leaks, looked at the top of the tank and it's dry too. At this point I'm assuming it's leaking on the bottom because plywood floor under it looks soaked with fuel. I haven't removed tank yet, hoping to do it this Sunday and I received new plastic tank yesterday and installation kitchen should come in today.
Do you think regular pressure treated plywood would work as new tank floor and new panel separating engine and tank?
I don't think Lowe's or home Depot carry marine grade in stock.

 

[Ron20324]

...I don't think Lowe's or home Depot carry marine grade in stock.

It has been a couple years, but Home Depot in Annapolis had a sign up by the commercial desk that they now (back then) carried marine lumber. BUT, then again, Annapolis is a waterfront town.

 

[SailormanDan]

I used 3/4" PVC board that was recommended by a marine mechanic, I think the pressure treated plywood would work OK for that purpose. I'm sure what was in there and last how many decades now was not anything more than plain plywood, not marine grade. Mine was also soaked with fuel when I pulled it all out, I also replaced the bulkhead between the engine and the tank because it was soaked with fuel.

 

[Hayden Watson]

Just remember to clean all of the diesel stink out when you are in there. I have found Febreze to work well at eliminating diesel odors from the boat.

 

[heritage]

Would like to see a close up picture of where the leak is in your old tank after you remove it. I replaced the fill hose on mine that was leaking some fuel on top of the tank. Also, I found the fuel vent hose had become brittle and replaced it. Not a fun place to work in!!

 

[Kommy000]

Alright got more questions:
I got my installation kit and it has those brass looking screw in connectors that go into the brass fittings on the fuel tank.
Am I supposed to use plumbing tape with those or any kind of sealant or just screw them in raw?
Also, I don't know if I will be able to save 1/4 tank diesel I got left in the old tank, so basically my boat will be in the marina slip with no fuel. Do you know if marinas ok with me bringing in empty can to fill up with their diesel fuel so I can get some into the new tank and get the boat going so I can get to the fuel dock? Or should I just buy some diesel at the local gas station and fill the boat up at the slip? Is there a difference between say Wawa diesel fuel and diesel fuel you get at the marina?

 

[heritage]

Our marina doesn't have diesel. All I have ever ever used is from local gas stations.

 

[SailormanDan]

It looks like yellow plumbing tape, but is fuel-resistant.
We don't have fuel at our marina and I've always bought mine at the gas station and used it without problems, it's probably cleaner than what the marina has. Don't use the old fuel without filtering it, safer to dump it.

 

[smokey73]

There is no real difference in the diesel fuel itself between what is bought at a gas station or at a marina. Both are Diesel Fuel and unless you are in a real farm area all highway diesel and marina diesel is low sulfur. Road taxes are paid on diesel that is sold at gas stations but because of the captive audience, fuel from a marina is still probably more expensive. Some marina diesel has additives but I'm not sure how effective they really are and you can add your own additives to limit bio growth and probably should anyway. As a plus, most gas stations go through diesel pretty quickly so you can be surer the fuel if fresh. Then again, if its an old tank at the station it may have contaminants in it.

The long and the short is, go ahead and get your diesel fuel where ever you can get it. Just be careful when filling from a fuel jug not to spill it and cause a fuel slick.

 

[Benny17441]

BUT, then again, Annapolis is a waterfront town.

So is St. Petersburg, FL which is located in Tampa Bay. There is an active yachting community here. Tampa Bay is a true bay with only one entrance and exit for tidal flow. None of the box hardware stores carry marine plywood here but a simple google can lead one to a retailer. Marine plywood is good for use in areas that could get repeatedly wet; pressure treated plywood will not last as long but could be good enough for repairs on an old boat if there are budget and convenience considerations.

 

[JimInPB]

The long and the short is, go ahead and get your diesel fuel where ever you can get it. Just be careful when filling from a fuel jug not to spill it and cause a fuel slick.

This touches on a pet peeve of mine. The new vent-less fuel cans, that are now on the market, tend to be very hard to dispense fuel from without making a mess. I've taken to making my own spouts to combat this problem. In my opinion, the "CARB" regulations have been poorly implemented, if not ill-conceived from the onset. They seem to have causes more fuel to be dumped into the environment then they prevented.

As for sealing the fittings on the fuel tank, you can find both tape & paste type sealants that are rated for use with diesel. Either will work. Some guys use both together. Just don't use the stuff that is not fuel rated. I get my fuel dope from a local shop called Mako Hose.

Also, if you are unsure of the condition of the old fuel in your tank, check your yellow pages or do an internet search for a local guy that does "fuel polishing". He may be able to help you out with either fixing up the old fuel or getting rid of it.

 

[Kommy000]

Alright, even more update on this project.
Finally was able to disconnect all the hoses and get the tank out. Thought I might be able to move the tank out with fuel still in it but I noticed that just by moving it a little the fuel started dripping from the plywood deck under. I'm guessing plywood was plugging the leak somewhat and me cutting the strap that was holding it to the tank released the pressure and the hole opened up more.
I ended up pumping about 6 gallons of diesel out and when I looked at the bottom of the tank there was a nice round pin hole in it with no rust. So have no idea if it rusted from inside or how that pin hole happened.
Removed the soaked plywood also and found more fuel under and under the muffler that's located under the plywood.
I like the idea of using pvc board as fuel tank deck but my question is , will it be ok right on top of the muffler.
I don't know if muffler gets hot or what.
I've attached some pics of the progress. Will do clean up and whole bilge clean up my next day off.

 

[heritage]

Thanks for the pics Kommy. I had assumed that your tank was plastic like my 84 H27. The exhaust pipe and muffler should never get very hot because of the cooling effect of the water injection. Failure of the raw water pump or a blockage of water at the top of the mixing elbow would raise the temp, but you should have the engine shut down quickly if that ever happened.

 

[smokey73]

Good Work. OH NO "project creep warning" but sometimes the potential savings are worth it in the long run!
It looks like the exhaust hose to the Muffler and maybe even the muffler have been replaced sometime since the boat was built. I think I'd replace the exhaust hose from the outlet of the muffler to the overboard discharge since you have everything out and easy access. Use new double stainless hose clamps (don't use the ones from an auto parts store with the holes in the strap, use the kind you have now but new.) As a general practice I have the screw clamps facing opposite directions. It looks like you don't have a very long run from the engine, so I'd go ahead and take the opportunity to replace that hose to the muffler from the engine. While you have the hose off you might want to check to see if your exhaust elbow needs cleaning or replacing. Labor for this is a lot easier in the state you have it now than with everything installed and the tank in place.

I'd also replace the two blue electrical crimps (and any other you find) with proper crimps with head shrink connectors and put some chafe protection around those wires where they go through the opening in the fiberglass on the starboard side and tidy up the wiring. Be careful about tying to many things together with tiewraps you can't reach easily as it it just makes pulling a new wire using the old one impossible. I might even run a spare "chase line" from the stern under the tank to an easily reachable point near the engine in case I ever wanted to pull another line for something. Just a few thoughts.

 

[SailormanDan]

I bit the bullet and replaced everything while I had it all apart, muffler, the old plywood (both under the tank and the bulkhead between the engine and tank), all the hoses, fuel tank, sound insulation. It was enough of a hassle to get the side panels, etc. out for access that I'm glad I bothered. Especially the muffler since it's under neath everything, but running new exhaust & fuel hoses was easier with the tank out of the way.

 

[jssailem]

Smart move Dan. Your wisdom will be noticed, at least by you, through the next 5 years.

 

[SailormanDan]

Thanks, @jsailem,
I figured that the old system had lasted 35 years, so things should be good for at least that long.
Now if only it were that easy to overhaul my internal parts so I'd be good for another 35 years.

 

[SailormanDan]

@Kommy000 - the Vetus muffler that I used as a replacement is plastic. I forget the max temp rating, but I think the earlier comment about the engine overheating alarm going off before anything else overheats and becomes a problem is sound advice.
I don't think you need marine plywood underneath the tank, I'm sure what Hunter originally put under there was just exterior grade plywood and that lasted 36 years. If it gets wet down there, you have other problems.

 

[CloudDiver]

Keep in mind the only thing 'marine' about marine grade plywood is that waterproof adhesive is used between the plys and it also has a lower tolerance for voids or other imperfections. When looking for good plywood use the term 'exterior grade' when talking to lumber yards, same stuff. In this application I don't think its necessary, you'd be fine with a standard 3/4" sanded plywood. I would just give it two coats of epoxy, sand, and paint with an enamel to keep it fuel/waterproof.
The suggestion to use PVC (starboard) is a good one but that stuff is expensive in that size. G10 would be great too but also mucho expensive. My local plastics supplier sells cut offs of this stuff so I usually go scrounging and find good pieces for $2 a pound. I actually have two big planks of 1/2" G10 that are about 30 inches long by 6 inches wide that would work perfect for that.
Speaking of planks.... forget the plywood. Just buy a nice piece of white oak or other suitable hardwood and cut two planks, still coat with epoxy and paint it with Bilge Kote (Interlux). Most good lumber yards have a fair selection of off cuts you can get cheap.

 

[JimInPB]

The suggestion to use PVC (starboard) is a good one but that stuff is expensive in that size.

I believe that Starboard is actually HDPE. I have seen both HDPE & PVC used in marine environments. Around here, scraps of either go for about $3/lb these days.