Water Tank Inspection Port

Feb 27, 2004
172
Hunter 335 North East, MD
The bad or good thing about the stay at home mandates is that I at least start thinking up new projects for the boat- The water tank in my 1994 Hunter is located under the V berth the top of which easily accessible by pulling up cushions and a wooden hatch. I was thinking of adding an inspection/access hatch in the top of the tank- the tank is poly. I wonder if anyone has done this and has any installation tips-

Thanks
 
Jan 19, 2010
12,362
Hobie 16 & Rhodes 22 Skeeter Charleston
Seems like a good idea. I would make it large enough that you could get a pressure washing wand or a brush on a stick down into the tank. SBO sells a 4". I would think a 6" would be better. Maybe use the "contact us" link on the SBO store and ask if they can get you a 6".

 
Dec 2, 2003
751
Hunter 260 winnipeg, Manitoba
Did that on our poly tank about the 2nd year we owned our boat. Works well. Each fall I open the access, sponge out remaining water, disconnect pump and blow out lines. In spring I wipe the tank with disinfectant, rinse, replace hatch, reconnect pump and fill.

Only difficulty is it’s a looong reach to the bottom of the tank from the v berth.

Used a screw in deck plate (4”) similar to the one posted by rgranger
 
Jun 11, 2004
1,621
Oday 31 Redondo Beach
This may be an ignorant question but why would it be necessary to inspect your fresh water tank if everything was okay? I follow Peggie Hall's recommended recommissioning procedure and have never had a problem.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
...Used a screw in deck plate (4”) similar to the one posted by rgranger.
.

And people tell me I have too much "stuff" in my place... Right next to the computer is a Marinco box of parts from all too many of their solar vents installed. I have two, 4.5 " "holes". I think if my large arm fits through, then you can probably use a 4.0 /// unless you NEED a bigger size. If I had the "plates", i'd send them freebie, but I only have the 2 rings and ss covers.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
This may be an ignorant question but why would it be necessary to inspect your fresh water tank if everything was okay? I follow Peggie Hall's recommended recommissioning procedure and have never had a problem.
:plus: This weekend I'll be doing my water system and will open the port and do an inspection wipe of the interior. If all's well, no worries, mate.
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
That's a good project. I don't see otherwise how you can be sure the tank is really clean of debris.
I followed Practical Sailor's advice and installed a strainer on the tank's vent hose to keep insects out.
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Dec 2, 2003
751
Hunter 260 winnipeg, Manitoba
This may be an ignorant question but why would it be necessary to inspect your fresh water tank if everything was okay? I follow Peggie Hall's recommended recommissioning procedure and have never had a problem.
I also follow Peggie’s recommendations during the season if needed.

I put our plate in primarily for ease of winterization. Did the winterization chemical one year, took months for the flavour to get out of the lines. Now I use a sponge to dry tank, disconnect pump, blow lines and done. In the spring a quick wipe down, reconnect pump, a bit of Peggie‘s brew for the lines and it’s done. No lasting flavours To the water.

Our system is quite simple though, pump, two faucets and maybe 20 feet of piping that all run downhill to a common point.

Also allowed cleaning of our tank after a fill from one marina that had a lot of sediment in the water. It was potable but not pretty!
 
Jan 7, 2011
4,723
Oday 322 East Chicago, IN
I put inspection ports on both of my water tanks.

I used 4” Beckson deck plates.

Cut the poly tank with a jig saw, vacuumed out the plastic bits, used some deck caulk and screwed them down on the poly tank.

around 11:50 on this video I am putting one of the tanks in and you can see the washout.


Greg
 
Feb 27, 2004
172
Hunter 335 North East, MD
Thanks for the feedback- I think I'm definitely going to do this one- beside a jigsaw I guess I could use a hole saw if I can find one the right size
 
Dec 2, 2003
751
Hunter 260 winnipeg, Manitoba
Hole saw will definitely work, even a Dremel, sharp knife, utility or sheet metal shears, etc can work. Polyethylene used for tank is relatively soft and easily cut.

back up screws on inside of tank with some hard rigid material to distribute load for better sealing.

start well inside of final opening and work your way out.
 
Jan 19, 2010
12,362
Hobie 16 & Rhodes 22 Skeeter Charleston
A four inch hole saw is going to run you about $25 at Lowes or Home Depot...

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Then it is going to sit in your shed until you die and your kids will sell it for $0.25 at a garage sale.
I keep one of these in my boat's took kit

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It is surprising how many uses I find for it. Although the blade is a hacksaw blade, it makes an excellent coping saw for jiging out a tight pattern. And the hack part is nice for lopping off the ends of through bolts so you don't snag them and get cut. And the saw will get used again and again.

Or..
A sawzaw with a fine tooth blade would also make a nice tool for cutting that hole... again, it is something you would use again. Porter Cable makes a nice one (I have one) and it is cordless. It is twice the price of the hole saw but you will use it a lot.
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Jul 5, 2011
702
Oday 28 Madison, CT
I am very happy I added the port to my tank. See my post in other thread as to why. Also, if you don't clean it you will be loading up your pump filter more often than you want to.
 
Dec 2, 1997
8,708
- - LIttle Rock
back up screws on inside of tank with some hard rigid material to distribute load for better sealing.
Not how I'd do it...nor would I use any sealant because all sealants dry out requiring replacement, which can be a real PITA job. Instead I'd put a rubber gasket (available from Beckson or make one..rubber gasket material is readily available from box and hardware stores) under the flange and secure the flange with screws...they won't pull out because there's no stress on 'em, so no "backing plate" needed. A rubber o-ring seals the cap.
Rubber also dries out, requiring new gasket and o-ring every 5-6 years...but replacing 'em is a LOT easier than scraping dried out sealant and replacing it.

--Peggie
 
Feb 27, 2004
172
Hunter 335 North East, MD
Not how I'd do it...nor would I use any sealant because all sealants dry out requiring replacement, which can be a real PITA job. Instead I'd put a rubber gasket (available from Beckson or make one..rubber gasket material is readily available from box and hardware stores) under the flange and secure the flange with screws...they won't pull out because there's no stress on 'em, so no "backing plate" needed. A rubber o-ring seals the cap.
Rubber also dries out, requiring new gasket and o-ring every 5-6 years...but replacing 'em is a LOT easier than scraping dried out sealant and replacing it.

--Peggie
Thank you Headmistress- that's very helpful

Nigel
 

RoyS

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Jun 3, 2012
1,739
Hunter 33 Steamboat Wharf, Hull, MA
I would use elastic lock nuts and machine screws to fasten. Easy to install nuts with cover off. Gasket is a nice idea.