CHB 41 Fuel Tanks Advice

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K

KME

Member
Joined
Jul 4, 2023
Messages
5
Vessel Name
Change of Course
Vessel Make
1980 Marine Trader 34DC
We are looking hard at a CHB 41. Everything about the boat ranges from acceptable to great. BUT, the fuel tanks are near term ticking time bombs. Port has a patch on the bottom, starboard has scale rust on the top, crud in the Racor. This is a single engine boat so there is a bit more room to move about, but not enough to pull a tank intact. I have no issue getting the old tanks out.

My question is, what have people done for replacements? Stacked poly tanks? I don't want to shift or pull the engine.

Thanks for your input.
Ken
 
Pretty common these days to add inspection ports, clean tanks and coat them inside with magic goop. I would look for someone who does this professionally, even as a DIY person I thik this is a place not to go cheap
HW
 
I would get a price on pulling the engine. I know you don't want to do that, but the insane amount of time you will waste cobbling tanks together or coating interiors has to have a value. Speaking of value, when it's time to sell, anything short of new tanks will be the Achilles heel as far as selling at market value.

Find a yard that routinely extracts engines and transmissions from boats, and get a price. Once done, drain the tanks and remove them. Find a tank builder that will replicate what you've removed, and the put the boat back together.

Yes, this is going to cost some money, but hopefully it's recovered when you sell.

Maybe post some pictures to see how simple or complex the engine removal is, or isn't. Another way to look at this is, unless the boat is of such little value, if you have an engine or transmission problem, they may need to come out. This project you can do at a time and a place of your choosing.

Ted
 
I did this a few years ago on a single engine CHB34. I attach a couple of files relating the options I considered and how I actually did it. You might find these of interest.
 

Attachments

  • CHB34 Fuel Tank Replacement Rev0.pdf
    2.6 MB · Views: 88
  • Cutting up a CHB34 fuel tank Rev1.pdf
    1.1 MB · Views: 39
On our last boat I pulled both engines, one at a time. It was quite easy. I built a crane to lift the engines up and stack it over the other engine. Once I got everything figured out it took less than 2 hours out and 2 hours back in. It was 3 guys doing the work. Easy peasy.
 
I have a CHB41, and the PO hired a company to replace one of the tanks, which rotted from the outside due to a leaking hot water heater. I think it was around $10k for the job - the new tank is three (I think) beautiful stainless tanks. We have twins, and they appear to have just pulled each engine & shifted a couple of feet toward the centerline, then back after the job was done.

The other tank had scale on the top from the typical leaking fuel fill fitting. Fortunately, I was able to remedy this by scraping off the scale to get down to good metal, cleaning (and cleaning and cleaning) then painting with POR-15 if I recall.

If you're in SoCal I can give you the name of the guys who did the job. They do it all the time for these old Taiwanese Trawlers.
 
I would much rather see aluminum tanks instead of S/S, it is difficult toweld properly. Aluminum is fine. Just make sure the aluminum alloy is proper. I also would go one size thicker than the minimum, cost difference will be negligible.
 
I replaced my steel tanks with fiberglass. Two 225-gal saddle tanks became four 110-gal tanks. For people skilled in mechanical stuff, removing the engine is no big deal.

One thing to consider is to my mind, tank replacement is top of the list for scope creep. There is so much that can be done while the engine is out - clean up wiring, engine room insulation, paint engine, paint engine room, repair/replace difficult to access items such as water heater or generator, etc. Also, sounds like a deck leak caused at least one of the tank issues. That of course needs to be addressed.

Comodave gave good advice about assuring proper alloy of aluminum - the wrong alloy will dissolve like Pepto Bismol around the mounts if/when it gets wet with salt water

Sounds like you are in the due diligence phase of purchase - are you sure this is the right boat for you?

Peter
 
Nick F said:
I did this a few years ago on a single engine CHB34. I attach a couple of files relating the options I considered and how I actually did it. You might find these of interest.
Click to expand...
that's a wealth of information. thank you!
 
Thanks everyone for your advice and input. One of the reasons why we're seriously considering this boat is an awful lot has been done in the last couple of years such that it is set up quite close to how we want it for how we will use it. Many of the sub systems and equipment have been replaced, upgraded or added. The decks have already been professionally done. Yes, there are a few spots in the boat needing attention, but are not deal breakers. From my perspective internally coating tanks that have rust and reduced wall thickness with a miracle goop doesn't make sense. The same can be said for installing bladders. Either strikes me as a lot of work, approaching that of new tanks. At this point I'm collecting budgetary estimates for: A. New duplicate tanks made in aluminum and B. 2 tanks per side duplicating the shape of the originals. Picture slicing the existing tanks in half horizontally. These tanks would slide in place without pulling the engine. I'm still exploring my options and costs. Once in hand we will decide what we want to do, meaning do I want to take the project on if we can negotiate an acceptable deal for the boat. The answer is most likely yes. As I said there are a lot of positives.

Anyone interested in a 1980 MT DC 34'. Power is a Yanmar 6LP-DTE with approximately 950 hours. Generator installed at the same time as the engine has approx 1300 hrs. Recent bow thruster, solar, new windlass, good canvass, davits, inflatable, no teak decks.
 
Tank material options in my order of preference...

FRP (not many folks can make these properly for fuel for anything less than an arm and a leg, but they are forever)
Aluminum (fairly straightforward and the most common)
Roto Poly (cheap, but you have to use off the shelf sizes, can't be fully baffled)

I would not use stainless, it has drawbacks related to weld embrittlement, and it's costly.
I would also not consider coating, cleaning a tank, even a new one, much less a used one, well enough to enable a coating to adhere for very long is nearly impossible.

More details on installation and design here...


https://stevedmarineconsulting.com/wp-content/uploads/2022/11/FuelTanksPt1-193-FINAL.pdf

 
Steve DAntonio said:
Tank material options in my order of preference...

FRP (not many folks can make these properly for fuel for anything less than an arm and a leg, but they are forever)
Aluminum (fairly straightforward and the most common)
Roto Poly (cheap, but you have to use off the shelf sizes, can't be fully baffled)

I would not use stainless, it has drawbacks related to weld embrittlement, and it's costly.
I would also not consider coating, cleaning a tank, even a new one, much less a used one, well enough to enable a coating to adhere for very long is nearly impossible.

More details on installation and design here...


https://stevedmarineconsulting.com/wp-content/uploads/2022/11/FuelTanksPt1-193-FINAL.pdf

Click to expand...
Thank you for your help and info Steve. I did get a couple of quotes and had a vendor I was comfortable with, but the seller was not willing to make any price concession, so the deal is not going to happen with me.
 
KME said:
Thank you for your help and info Steve. I did get a couple of quotes and had a vendor I was comfortable with, but the seller was not willing to make any price concession, so the deal is not going to happen with me.
Click to expand...
Fwiw. How much were the quotes? Just curious for a ballpark figure.
 
Silverlining said:
Fwiw. How much were the quotes? Just curious for a ballpark figure.
Click to expand...
I asked for quotes two ways. The 1st was to duplicate the existing tanks should I decide to pull the engine. rounded up a few dollars $4,400. The 2nd was to duplicate the existing tank profiles but use 2 tanks layered per side if I decided not to pull the engine. Again, rounded up a few dollars, $6,400. These would be aluminum, and certified.
 
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