I had seen this project 1st on Netboys site a few years back (linked on home page). Using a deck lid, primarily used on boats, You cut a hole in the top of your water tank, install deck lid for access inside. For cleaning-just to see, but what finally got me going-using the port to fill the tanks when using jugs!.
These things are designed to be water tight, the lid unscrews easily for access. Yes this came up again in a discussion on RV.net last night. Fella had a fill hose adapter blow off into his tank-"How do I get it out. or does it matter?" Consensus was, Well since the hose is inert shouldnít hurt to stay in there but the "if you had an access port..." came up. One guy says he'd like to put one in to check his level. Then another fella mentioned he mostly used his port when using jugs to fill the tank.
DOHP! in the all the years I've thought of this project, camping & making 20 trips with a gallon jug, holding a funnel trying to refill the tank -just never occurred to me. Ya know if we had a tank port we could just dump it in. Could also use the Britta or similar to filter the water before dumping.
Any way I looked on line, deck lids range (for the same brand $10-30) then I saw you could get them with clear lids. Hmm that would be kinda nice. Anyway on my home tonight I stopped by the local RV/Marine shop. I said I was kinda thinking of adding an access port to my water tank, folks are using "deck lids". He walks over to the shelf. " this is all I have, just came in, a 6" deck lid with a clear lens. $16". I said sold. Went to the hardware, picked up (12) 1" 8-32 phillips CS Stainless screws 5/8x #8 fender washer & nylok nuts, and tube of silicon. I Highly recommend getting socket head countersunk screws, I didn't only spun the head on 2....
Hereís the new deck lid, checking if you can really see thru the lid, I've got it wedged in the chest bout 18" off the floor -you can read the box. Nice
I modified the ring, adding 6 more holes. This helps insure it doesn't leak or warp and give more support to the tank top.
Ready to start. Modified ring, clear lid and o ring. I used fender washers but making a backup ring like Netboy did might be a good idea (use plastic cutting board).
This is the step to bed, under the carpeted board is the water tank, 4 screws hold it in place. I was thinking of adding a piano hinge- ,except Iíd have to cut the board, part is under the slide sooo...then again I may just add an internal support (because the lid actually holds the front box wall, not a lot of structure). Add a block on the back camper wall that keeps board from flipping and adding some kind of bracket/ latch to the front, then the board could just slide off. Maybe later.
Traced the position I wanted then used the template to draw the cut line. Were committed now. Yup that's a lot of wire....
Used a utility knife. Only broke 2 blades. Though the tank is easy to cut itís not easy using a knife to cut round hole. Take it SLOW. If I were to do this again, Iíd drain tank and use a saw, then clean the tank.
Finally.. hole. I placed the ring in the hole, marked one screw hole. Drilled then replace ring with one screw to keep it from moving and drilled rest of holes. I held a wet paper towel underneath to catch any shavings, but most spirals out. I used Margaretís kitchen strainer to catch a couple of fallen pieces of plastic-it floats? Oh see the screw in the cut out-when I only had about 2" left to cut, I could slide in my hand in to support & I put a screw in the scrap to hold it so it didn't fall in tank.
Used a 1/4 bead of silicon in the corner on the snout that protrudes into tank and flange, a small bead around perimeter. Small dab on each washer & under head of screw. Sequentially tightened, the silicon made it slick-hence the phillips head were really hard to hold. As noted before, If I ever do this again Id use socket head counter sunk or you could use washers on top and hex cap heads might be easier. Any way itís done- Iím liking it. Refilling the tank will be really easy. One thing that surprised me how clean this 9 year old tank is inside. I was really expecting a mess. Iíll still clean and rise the tank once the silicone cures.
Ok-Next making a tool to fit the lid & modify the tanks step board for easy access.
Tool for opening the lid. I cut 2 wedges, sanded to fit the concave interior of the recesses in lid.
To insure alignment I placed the 2 small blocks in the lid recess, applied wood glue, put the cross piece (handle ) and lightly clamped. Removed after couple of hours and used 3 nails each side. Sanded and sprayed some clear on . Also drilled for lanyard to tie off in water tank area.
Here you can see the profile I needed to match.
Lastly modify the box top for getting access to the new water tank access port
Nice would be a simple piano hinge. But part of the board is under slide, so id need to cut-hmm I just re carpeted, there's no structure to the box (it relies on the top being screwed down for integrity) and there's no room to add anything to support the hinge side or reinforce the outer box wall to the camper wall. He hawed around for a while then decided all I needed was to duplicate the original top, put a false top on the box , then it wouldn't need the carpeted board for integrity. I could make the top board just slide in. I used a piece of plastic cause that's what I had laying in the shop. Works well but Iíll probably at some point add a piece of flat bar with cross flanges welded so I can secure the outer box wall back to the camper wall. Piece of 1/8-1/4 ply would also work for the false top.
I used 2 simple hook & eyes to hold the board front on.
I also added 2 small angles at back edge of board to insure it doesn't tilt up. Board slides in pretty tight. Because Ill be pouring thru 2 holes Iím going to find a plastic bowl that will reach into the tank, cut the bottom out & install screen. Or a large funnel. It'll act as a splash guard when refilling with jugs (juggin) and catch any large objects that are not supposed to be submerged in our drinking water.
Couldnít find a funnel or bowl that was short and also big enough around, so made one. Iím sure thereís something out there. Used some scrap poly sheet I had. Formed approx. 11 1/2 od X 3 id X 5" cone. Silicone the lap and used #8 x 1/2"screws& nuts. I was going to get some screen and happed to see this old tube bumper cap on the bench. Wow-perfect fit, just plain luck, got a lip so canít push thru, extends the reach. Drilled it full of holes. If the water chokes Ill completely remove center of cap and put coarse screen on it. It just slips in didnít seal
As Iíll be pouring thru 2 holes when using jugs-this will work great. Screen (Cap) also extends the reach into tank.
Final note: Another reason for adding the tank access port. After I finished the install decided to clean & drain the tank. Realized I could put a hose in thru the window and siphon it out. With hose in tank, slowly turn on hose attached to faucet-once air is out turn off water un screw hose from faucet (keeping it lower than tank) and tank should drain. WOW like in 15 minutes instead of normal hour or more using the tanks drain. Plus you can move hose around to suck any debris off the bottom.