Fresh Water Tanks

I'm in the process of cleaning and doing a bit of re-plumbing of my two fresh water tanks.
I'm concerned about these pits, one, quite large, the size of a dime, that have formed between the tank the inner coast of whatever that is.
As of now, they are not leaking.

My questions:

How big a concern are this pits?
If significant, possible solutions?

I've also attached a picture of the Maretron tubes (used for the ultrasonic sensor). there is a lot of Calcium deposits on the tubes (it's been three years since I opened these tanks up to look).

Thoughts?

Pictures will be in next post from my phone

Port tank




Stbd tank






Maretron tubes

Which material are the tanks made from. steel or aluminum.

The pits, some of them, look reddish which would indicate rust so steel for the tanks but is that the case?

I'm not sure. Metal, but it's fibreglassed on the outside and has a two layer inner coating.
I picked at that spot, while it seems brown, it doesn't seem to be red.

Hi Richard, I can’t answer your question but a magnet will tell you if it’s steel. If it isn’t steel, it’s most likely aluminum.

If you decide to replace the tanks, this is the place to buy new ones.
https://ronco-plastics.com/newRonco...rsProducts=0&totalRows_rsProducts=450&catID=1

They will install the fittings where ever you want.

Possibly a silly question but do they build the plastic tanks in place ?

Simi 60 said:

Possibly a silly question but do they build the plastic tanks in place ?

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Could be done though never heard of it.

Building out of glass and epoxy or vinylester/polyester may be a better alternative for build in place.

Many of the pieces sometimes can be fabricated out of the boat and my choice if/when my holding and water tanks need replacing.

My tanks are stainless and have the occasional rust spots and rust on welds like a lot of stainless....they are uncovered in/out.

If Dauntless's tanks are stainless and covered for some strange reason, the magnet trick wont necessarily work and may subject them to more rust than an uncovered tank. But I doubt KK would cover a stainless tank, and with the deposits on the sensor, I would lean towards aluminum tanks and that's why they are coated. I would think steel would not even make the list on such a small vessel (unless an integral tank on a steel boat).

Richard: We’re hull number 120 and our tanks are fiberglass and I believe all KK42 water tanks are the same. We have blisters on the insides but nothing I worry about. The tanks are integral to the hull as the build plans show. Unless your tanks are leaking, you should be fine.

Larry M said:

Richard: We’re hull number 120 and our tanks are fiberglass and I believe all KK42 water tanks are the same. We have blisters on the insides but nothing I worry about. The tanks are intrigal to the hull as the build plans show. Unless your tanks are leaking, you should be fine.

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I’m with Larry. I’ve had Salty Lady’s (hull 113) tanks open, I cleaned them and an of the opinion that they definitely fiberglass.
I have seen some of the tops fracture probably due to filling to fast and having vents plugged.

I’m working on replumbing the outgoing valves as so I can control which tank is being used from the access panel under the stairs. I’m keeping it simple and not changing the valves but rather leaving them open and running the line to and from new valves under the stairs. My concern with changing the valves is breaking something loose on the tank.
Going to use two 1/2” fuel ball valves from Defender @ $28 each since they have feet I can screw to a piece of plywood being attached to the tank using sika 291. I’ll use the same size tubing and flare fittings as exist on the rest of the system. It might be done by the time your in NY.

Larry M said:

Richard: We’re hull number 120 and our tanks are fiberglass and I believe all KK42 water tanks are the same. We have blisters on the insides but nothing I worry about. The tanks are intrigal to the hull as the build plans show. Unless your tanks are leaking, you should be fine.

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Oops

Larry is right. They are fibreglass.

Not leaking, so the plan now is to continue business as usual until they start to leak or I die, which ever comes first.

Dcbeach said:

I’m with Larry. I’ve had Salty Lady’s (hull 113) tanks open, I cleaned them and an of the opinion that they definitely fiberglass.
I have seen some of the tops fracture probably due to filling to fast and having vents plugged.

I’m working on replumbing the outgoing valves as so I can control which tank is being used from the access panel under the stairs. I’m keeping it simple and not changing the valves but rather leaving them open and running the line to and from new valves under the stairs. My concern with changing the valves is breaking something loose on the tank.
Going to use two 1/2” fuel ball valves from Defender @ $28 each since they have feet I can screw to a piece of plywood being attached to the tank using sika 291. I’ll use the same size tubing and flare fittings as exist on the rest of the system. It might be done by the time your in NY.

Click to expand...

I'm doing the same. Which caused me to open them up in the first place.

My solution is to put nipple off current 1/2" valve, which will be kept open.
Each of those feeds will then go to three way valve now located under arms behind first step in passageway staircase.

I'll attach first valve to wall.

So to change tank feed, just reach under stair and move handle 90°.

Thanks for all the advice.

Richard

When you get to Japan (I forgot whether that's in your plans).....

I suggest a one time fill of Sake to draw any water from the tank sides and reduce blisters. Highly recommended by fiberglass tank manufacturers. Rum would have worked in the Caribbean when you were there.....

How you dispose of it is up to you...

Miller tank co, burkettsville pa builds first class pot water tanks ...if top quality is desired and 5 yr warranty