Clean Monel potable water tank or replace???

[glcalahan]

I am referring a 1972 Pearson 33 that sank in its slip roughly 5/6 years ago. It was raised in two days and previous owner had Yanmar torn down BUT the boat has sat basically unattended/unused. Now....the water tank. I have no idea what is in the tank but am convinced the tank had water intrusion. If true....there is no telling what is growing in there. I am likely going to have to cut in an inspection hole. I already have had health issues with black mold and have no interest is putting contaminated water into my system. To clean out baffled monel water tank and hope I get it clean or cut it out is my question? How would I clean or how do you suggest removing the tank?

Thanks

GLC

[Terra Nova]

Install clean-outs large enough to reach through with your arm and a spaghetti mop to thoroughly scrub all interior surfaces. A remote (fiber optics) camera is handy for 100 % visual inspection.

[glcalahan]

I forgot to mention it is a 60 gallon tank and I poured 6 gallons of bleach and topped off for 2/3 months. I have not looked for opening inspection windows and don't recall seeing such a product. Suggestions? Thank you Terri!

[Terra Nova]

This is the style I've used successfully.
https://www.fisheriessupply.com/whal...spection-hatch

[hellosailor]

Monel is like gold: You don't throw it out when it gets dirty.

Doesn't matter if the tank was submerged or just laid up over the winter, water tanks need to be accessed for cleaning inside. Check the price on new monel tanks--if you can still find them--and you may be motivated.(G)

[glcalahan]

Thanks for the input. Witthout pulling tank out I have no idea of dimensions. I didn't think monel was still available/used anymore.

[alley]

Ditto what the others have said. Cut ports for clean-out/access in your tanks. Monel is worth gold and is very resistant to corrosion - better than stainless, I'm told.

I have an Alberg 35 and all of its tankage (except the holding tank) is Monel. Wonderful stuff. I removed the gas tank and cleaned it out when I repowered with a diesel a few years ago. Some time with a scotch-brite pad and it had a mirror finish. I used a Dremel tool to cut an access port to remove 50 years of sediment that accumulated inside the tank and provide a future inspection port.

Here's a photo of the tank after I got it cleaned up and was reinstalling it on the boat.

[Dougtiff]

Install a couple of 8" screw-deck plates.

[glcalahan]

Well all this information has given me cause to rethink this issue. I may go ahead and remove what appears to a bitch to remove and install inspection Windows. Maybe see if I could get it steam cleaned too. BTW....what is monel anyway??

[peghall]

Everything you wanted know (and prob'ly a lot more) about monel:

https://en.wikipedia.org/wiki/Monel

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

[glcalahan]

Thank you all for the help!! I just don't want to be drinking contaminated water. I simply don't know of the tank had sea water breach. It was down for less than 2 days and Yanmar pulled and cleaned. I did have the Yanmar running at least. Every nut and bolt is rusty. I mentioned earlier in thread that I put 6 gallons of bleach into the tank and topped off the 60 gal tank and let it sit for 3 months. BTW....to my friend that suggested the 8" deck plate: thank you! I went to West Marine and found them!! Thank you!

[Cheechako]

It doesnt get any better than Monel. You should have a cleanout anyway. Get it cleaned up.
I doubt much seawater got in there anyway, thru the vent hole I suppose, but there's no pressure release to allow it in.
You should be able in many cases to put in a clean out without removing the tank.
However, you may find that other things from sinking are a bigger issue. Are the timbers etc under the floor dry or moldy?

[glcalahan]

Dry....in part because the boat has been on the hard a year as I rebuild her. Again...the boat sank , I think 5/6 yrs ago. It sat unused and seldom checked since than.

[Lepke]

The bleach killed anything in there, but all the dead organisms bodies are still there. Drain the tank, Rig a small pump, add fresh water, a house filter and circulate for a few hours or days. If the filter doesn't plug, go to a smaller micron. Your tank will be plenty clean enough.
Also, don't forget to flush the tank vent tube with a bleach solution.

[glcalahan]

Great point Lepke!!! Thank you!