Removing old diesel tanks

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Fotoman

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Nov 12, 2009
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The original steel tanks are still in place (new plastic ones were installed at some point). I'm thinking of removing them eventually but it's not possible to just take them out as they are too big. Can I cut them in pieces after making sure they are empty? Is that dangerous?
 
"Is that dangerous?"

NOT if they really are empty.

A chisel at the lowest point will get that last 1/2 cup .

An air chisel does a less messy job than a big grinder fit with a cut off wheel.

A small grinder like the muffler folks use will be handy too.

Wondering how new tanks were installed with out removing the old tanks and not screwing up the boats center of gravity?

FF
 
Why take them out!* I plan on leaving them in place and using them as the frame work and support for the new tanks.* I dont understand your comment (new plastic ones were installed at some point)?
 
FF wrote:

Wondering how new tanks were installed with out removing the old tanks and not screwing up the boats center of gravity?

FF
Well, that's why I want to remove the old tanks. The new ones were installed aft of the old ones and the surveyor pointed out that it could have an effect on the overall stability. The new ones are much smaller but still, I don't like the idea of being on a boat that is not well balanced (I'm used to sailboats so I'm a bit anal on this).

So if I make sure they are really empty, I don't risk an explosion or a fire by cutting them up with a grinder?

*
 
Grind away. Many yards remove them with a lot less mess by using a reciprocating saw and a box of blades. If it was me I'd use the saw method vs throwing grindings every where.
 
If you're really paranoid, before you start cutting, throw in some dry ice (using the appropriate gloves, etc).* The cold CO2 is much heavier than air and will displace any oxygen in the tank.* And no oxygen == no risk of bad things happening inside the tank.
 
Chris Foster wrote:

If you're really paranoid, before you start cutting, throw in some dry ice (using the appropriate gloves, etc).* The cold CO2 is much heavier than air and will displace any oxygen in the tank.* And no oxygen == no risk of bad things happening inside the tank.
Interesting idea. Thanks! (pun intented)

*
 
And no oxygen == no risk of bad things happening inside the tank.

Depending on the engine room ventilation , this could be a DEATH SENTANCE for the tanl chopper.

Can you train your mother in law ?
 
I took a closer look at the tanks last weekend. I can't believe how big they are. They run pretty much the entire lenght of the cabin house. The new ones are much smaller. I'll save a lot of space by removing the old ones. And since I won't do any extended cruising the smaller capacity will not be a problem.
 
And since I won't do any extended cruising the smaller capacity will not be a problem.


Actually you will have fewer problems with fuel in storage .

FF
 
A friend had his cut out by a guy with a portable plasma torch he was happywith the job and had no problem. I don't have details on what sort of fire prevention
Steve W.
 
Whatever you do, be damn careful!

While at a wilderness fish camp in S.E. Alaska 5 years ago, we were trolling for salmon about 2 miles off the fish camp's beach when we heard a loud boom. An employee of the camp was cutting a hole in an old rusty diesel tank. (about 250-500 gals.) It had set on the beach for years, rusting away. I don't know if he was using a mechanical saw or a torch. All I know is that he was blown about 75-100 feet, burned very badly and died in Seattle after a mercy flight.
 
A friend had his cut out by a guy with a portable plasma torch

I would be very wary , most GRP boats use a resin that is very hard to stop from burning if lit.

Look at any photo of a burnt down boat , or boatyard ,all the boats are gone to the WL.

Of course the 2c or 3c a pound difference in resin cost would have been paid IF FIRST PURCHASERS had been knowledgable enough to Demand it.

HETRON FR , if you are flush enough to request it on your next boat.
 
Fotoman wrote:[Well, that's why I want to remove the old tanks. The new ones were installed aft of the old ones and the surveyor pointed out that it could have an effect on the overall stability. The new ones are much smaller but still, I don't like the idea of being on a boat that is not well balanced (I'm used to sailboats so I'm a bit anal on this).
So if I make sure they are really empty, I don't risk an explosion or a fire by cutting them up with a grinder?]

Can I ask an obvious question, the answer being not so obvious?* I'm with Phil here (Hi Phil, long time so see), why bother to remove them, with all that hard work and attendant risk and expense, if you don't plan to use the space to increase your fuel capacity?* I have a similar vessel, similar situation, but I have just closed the taps (empty), and look on the old tanks as buoyancy - maybe if the ER flooded it might help hold her up until help came?* If I was going to use the space at all, then like Phil, I'd just remove the end and use the space to hold a new suitably-sized, custom made, fuel grade plastic tank for longer distance running, linked in such a way they could be left empty if not needed, to minimise stale fuel potential.* They do not significantly affect your trim empty.* My tanks, water and fuel, are even further aft in the lazerette, yet do not adversely affect stability or trim, as it is the widest and lowest part of the hull.* The original tanks in their normal position are set so high it would worry me a bit what effect they would have on righting moment if full, to be honest.* I was also a yachtie, and a bit anal re that issue.
Peter B

*

*


-- Edited by Peter B on Thursday 21st of January 2010 06:55:25 AM

-- Edited by Peter B on Thursday 21st of January 2010 06:57:34 AM
 
The original tanks in their normal position are set so high it would worry me a bit what effect they would have on righting moment if full, to be honest.

They might be high to smooth the roll.

Most inshore boats carry full fuel and the added time to roll (esp if the boat has hard chines) might be a blessing the orig NA built in.

FF
 
When we bought our CC Endeavour our fuel tank had been installed in the keel under the engine and our 85 gal tank had 30+ gallons of water in it. *The top of the tank looked like swiss cheese. *We emptied the fuel, pumped it out into temp tanks and went to town with a sawzall. *It came out in pieces, *any size and shape we could cut. *Because the location of the tank, it was foamed in place which stank of diesel as well. *Our new tank was custom made of fiberglass, from a mockup made from cardboard. *We lost about 15 gallons because the tank had to be installed from inside the boat and allowances made for the height of the opening. * I guess you could sell the metal for $$$. *It was had work, but worth the effort an I no longer had to run to the engine room to drain the fuel filter of water. *We had the fuel filtered and the water had settled in the temp tanks anyway making it possible to reuse the fuel! *Hope this helps.
 
I started the work this weekend. Here's the before and after shot. A few hours next week end and the port one is history.
 

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Fotoman,
Way to go.
Big job ahead but it is best to get rid of the s***t and then install new tanks that are purpose built with sumps, drains ,vents& proper self closing gauge glasses etc.
You will be extremely happy with this decision.

Benn
 
With all the problems of water and other crud in tanks why aren't they all equipped with a sump and convenient drain?
Steve W.
 
Fotoman wrote:

The original steel tanks are still in place (new plastic ones were installed at some point).
Good job getting the old tanks out.* From the looks at things none to soon.* Great pics.* Where are the plastic ones?

Larry/Lena
Hobo KK42
La Cruz, Nayarit, MX

*
 
I am jealous of your great access to the tanks! My monk 36 has a bulkhead between the engine and the tanks, making access a nightmare if they ever needed to be replaced. I'd have to cut out the bulkhead and then cut out the tanks...yuck!
 
Larry M wrote:

*
Fotoman wrote:

The original steel tanks are still in place (new plastic ones were installed at some point).
Where are the plastic ones?


*
You can see one behind the old tank. It's grey.

None too soon indeed. The bottom and the back had holes in them. I could take out big pieces with my hands, making the job easier.

*


-- Edited by Fotoman on Monday 8th of November 2010 08:02:10 AM
 
That's it, first one gone. I can't beleive all the storage space I will have.
 

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A little bit of elbow grease, some nice white Bilgecote or similar, a mattress and you could sleep a couple of extras down there.
 
Starboard side done. I hurt everywhere.
 

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Is that old gate valve history?
 
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