Water tank inspection port

[peterg]

Charlie- I really never gave much credence to the plywood tank top being a structural member. The rear wall of the tank acts as a structural stiffener and the fiberglass surround that the wooden top fits into also renders additional stiffening to the bow area. I experienced no detrimental structural effects from the total removal of the rotted cover- which will be a source of odor and potential mold if not removed and replaced. My new cover was easily removeable, with no screws or adhesive holding it down, and no water sloshing around on it to cause deterioration.  . I saw this as an advantage from the viewpoint of access to the bladder tank, as well as some additional storage area under the cover. That said, if you are apprehensive about possibly compromising this area of the boat, I would make a cover of 5/8" plywood, glue and screw it to the original fitment area, and install a 12" x 18" removeable rectangular hatch- readily available from any marine supply house or eBay.I would install a flexible    bladder tank and have easy access to it through the large hatch. I forget who I bought the bladder from, but it was a 26 gallon affair that fit perfectly in the old tank area. I'll check around to see if I can find a receipt. Good luck with the project!

[deisher6]

Thanks for the information it is invaluable before starting a project.  You are absolutely right about the mold and smell. As soon as it warms up some, I will take the top off and then consider what to do from there.

Again thanks.

regards charlie

[wes]

Boy, I'm dreading the removal of the old plywood top. They must have used a whole tube of 5200. Love the idea of the bottle jack, but I'm sure it will also need a good dose of Debond.

Peter, how did you keep the new flexible tank clean? No way to get inside to scrub it, I assume. Did you have a regimen of bleach treatment?

Wes

[peterg]

Wes- I have been using flexible tanks for quite a number of years, and I have found that a couple capsful of bleach at each fill-up kept them free of nasties. At the end of the season, half fill the tank with water and a bit of bleach and slosh it around, then empty the tank. Do this a couple times before storing and you should be clean. An in-line filter before end use fixtures catches most anything of a particulate nature. Be careful where you fill your water tank......I have filled up at a marina in Long Island Sound and ended up with a bunch of crud in my tank! Had to do multiple flushes to totally clean it.

[jimyoung]

Thanks for all the activity on this subject.... I am needing to do the same thing to Miss B. so have been following closely. By-the-way I have found that 3M's General Purpose Adhesive Remover works wonders in not only cleaning up 5200 when using it, it also is really good at breaking down cured silicone as well.....  My $.02 worth.  Keep adding posts, pictures and ideas on this!

[peterg]

I just re-discovered my source that I had used for 26 gallon triangular flexible water tanks (and 15 gallon poly holding tanks for 27's) at the best prices........ foreandaftmarine.com   Just in case anyone is contemplating some upgrades.

[deisher6]

Here's a 31 gal version...  http://www.navimousa.com/Water%20Tanks.pdf    I was thinking that two might fit.  This project is definitely coming up soon.  First though I have some teak for a cockpit deck and just bought another piece for drop boards. 

I brought a chuckle to the office yesterday when I picked up the wood for the deck.  The owner had shown me some cut offs that he said were free.  A couple pieces of mahogany caught my eye.  So after I paid for the lumber without thought I asked the lady (owner's daughter) if I could look through their shorts for a couple pieces of mahogany! 

Wound up with a cutoff from another yacht owner's hatch project, still $24/BF.

I will take pictures when I get started.

regards charlie

[wes]

Charlie - what's your source for teak? I've been planning a trip up to World Panel Products in Windsor NC (recommended by the boys at my boatyard). Open to better ideas though.

Wes

[deisher6]

Hey Wes:

Precision Moulding & Woodworks, Inc.
908 George St.
New Bern, NC 28560

Ph# 252 638 3845

They are abut 3-4 blocks from our house.  I first went to them out of curiosity.  I had 17, 4/4 oak boards that I needed to plane to 3/4.  They were glad to do it.  I had them do three sides.  It took about 45 min.  Charge was $34 for an hour of shop time.

Their stock teak is 8/4 X 10-12 in  X 8-10 ft.  The best deal is in their cut offs from other orders.  Do not hesitate to bargain.  

They have just finished several hundreds of sqft of 5 X 3/4 tongue and groove purple heart flooring.  I would really like to see the finished floor....

regards charlie

[deisher6]

Have started on the water tank top replacement project.  Have about two hours into it so far not counting a trip home for a saber saw.  Started out with screws, bring a fresh battery.  Worked on the aft end and tried to cut out some of the 5200 using a thin pry bar, a utility knife and a wood chisel.  Attempted to pry the top loose.  Not an easy task.





Considered trying the hydraulic jack to force the top off.  Decided to saw around the top of the tank leaving about 2 inches of the top.



The remainder was easier to reach and work on, but there seems to be no really easy way to remove the rest of the top.  Tomorrow I will try chisels (resharpened) to remove the rest of the top. Then acetone & scotch brite pads to clean up the edge.

The top was funky, moldy and stank. It also fit out the hatch with room to spare, albeit it is two inches smaller all the way around.  I do not have a sea hood, and do not know if that makes the hatch smaller.  I plan on making a full size pattern and try the fit again to make sure of the fit.  Not sure what I am going to use for a replacement.



I am open to any suggestions.

More tomorrow.

regards charlie

[wes]

Charlie - the tank itself looks pretty clean. No mold or bad smell other than the rotted cover? Any cracks/leaks in the tank?

For replacement, I'm thinking something non-wood, impervious to water. Plexiglas? What about StarBoard? I looked at the specs and it says "resistant" to water, but there's no info on using it in contact with water (esp. potable water).

I'm very interested - keep us posted!

Wes

[peterg]

I replaced the tank lid on my Orion27 with marine plywood with a layer of glass cloth and resin on the bottom to provide waterproofing. Never had a problem with it. On the CP27, as mentioned earlier, I put in a flexible tank with a removeable varnished plywood cover. Worked great.

[deisher6]

Thank you Wes and Peterg for your suggestions.

Removed the remainder of the top and the rest of the 5200.  Wes, I think your estimate of how much 5200 Hutchins used was wrong, they used at least a tube and a half.  Might still be a little loopy from the solvent that I used to clean off the last of it.

There were some small cracks at the forward edge of the tank.



The top was 1 inch cabinet grade plywood.  It is a trapezoid with bases of 6 and 47 inches and an altitude of 43 inches.  I just ordered a 48 x 54 x 3/4 sheet of StarBoard from West Marine.  It should be here Friday.   It was right at $400. The StarBoard saves me the time of having to fiberglass a piece of plywood. I was leery of using Plexiglas because of its brittleness.  I could see cracking the edges when screwing it down.  

Considered just putting on a removable cover and using bladders.  It is a good recommendation and a real workable solution.  However I really like the 50 gallons of fresh water, and the set up is good for fill and venting so a new top it is.

Speaking of venting, when pumping the tank dry from about 1/3 full, there was suction on the inspection port when I removed it.  Will check to see if some critter has plugged up the vent before I reassemble.

I noticed that in several places there was no 5200 around the screws on the lip of the tank.  This was particularly evident on the forward edge of the top.  The plywood on the forward edge was damp and deteriorated.  Elsewhere I think that tank probably leaked a little into the bilge when the fresh water was against the seam.   The membrane under the top was not originally one piece adding to the deterioration.

When I install the new top I will ensure that the old screw holes are covered with 5200, and that I use enough to have some squeeze out inside the tank.

Made a pattern to test the dimensions and to see if it would fit through the hatch.  The dimensions were good but it did not fit through the hatch.  I was able to flex the one inch styrofoam insulation that I used enough to get it through the hatch.  You would never be able to do that with anything over 1/2 inch plywood.  Even that would be tough.  I am hoping that the starboard flexes just a little.  If not I will probably look at putting a half lap joint on the forward end of the top and installing it in two pieces.



The pattern fit well.  I will use a 1/4 or 1/2 round over on the bottom edge of the top.



Have about 3.5-4.0 hours into the job now.

To install the new top.  After getting a good fit, Should I use fast dry 5200, set the top and let it sit for a day or so before screwing it down?  Or screw the top down right away?

Again thanks for your suggestions.  (I really hope that there is some flex in the StarBoard (+;!!!

regards charlie

[wes]

Personally I would use 4200, since this is not a structural joint and you mainly need sealing, not super powerful adhesion. Some poor fool will curse your name 20 years from now if you use 5200.

This might be one of those rare situations where silicone caulk makes sense. Easier to remove in future, safe for potable water, and it's an invisible area that will never need to be painted. Just a thought. I'm extremely cautious about silicone normally but this could be an exception.

On balance, I vote for 4200.

Wes

[MacGyver]

I had to mess with something similar, oddly installed in a macgregor 26. What a job...... anyway, I am watching with great regard to the job, your doing great.

I vote 4200 for what it is worth. I try to avoid silicone just due to its very nature. And agree with Wes, 5200 is a real job for the next guy.
4200 should do wonderfully.

I kinda wish I was there to see all of your work in person...... Please keep the pictures coming, I find it very interesting.

Mac