3607 waste tanks replacement

[km1125]

Just finished replacing my fwd waste tank. The rear one sprung a small leak several years ago and I did a temp repair to it but haven't replaced it yet. We stopped using it a couple years ago knowing it had to be replaced and we were still able to use the forward tank. I had been plotting to replace both tanks at some point but was discouraged at the pricing (including shipping, which was an additional 50% of the tank price!!!). Well, the fwd tank sprung a leak this year, so I was forced to address the issue.

The tanks are each 40 gallons, which seems huge to have 80 gallons of waste on board, especially considering how we use the boat and compared to what's available on any of the newer boats. I contemplated several options and checked out pricing of either going to a single tank (40 gal or larger) or going with two smaller tanks. Using a smaller tank - especially in the fwd compartment - would also allow for some additional space for something like an inverter.

I ended up getting tanks from greatlakesskipper. These are tanks originally spec'd for a Larson boat but fit the dimensions I needed. They are rated at 29 gallons each but when you actually measure them and do the calcs they come out to about 34 gallons. I also remounted the fwd tank a bit more aft and to the port side so there's a lot of extra room in the compartment (it sits under the dinette seating). I'm also adding the iSeries tank monitor system, as I never had a monitor for the waste or potable tanks and always had to open a compartment to visually check the levels.

I have lots of pics but have to upload them and edit a bit but will post. I got the front tank done but the monitor system had a problem so a new one is on the way.

[g36]

Greatlakesskipper is a great place to shop

[km1125]

Source of the post Greatlakesskipper is a great place to shop

A huge difference was their shipping. They charged ~$30/tank, whereas all the others were more like ~$150/tank.

It was funny though, because I bought two the shipping changed to $150, so she entered both separately so they'd ship for $30 each. I was also pleasantly surprised how quickly they arrived. Ordered on a Tuesday and they were at my house on Friday.

[km1125]

Well, I finally got around to uploading some pictures, so I'll document this thread with what I have. I just finished installing the tank monitor that I have, but don't have pics uploaded of that yet.

Here's a pic of the old tank with some weird deformation in it. This was on the back side of it, so I had to stick my camera back there to see what was going on. I couldn't slide the tank out because the opening was just over 18" and the tank was 18" but with this deformation sticking out it wouldn't fit through the hole. Once it got it out I found that point is right where the leak was, as if the plastic shrunk and pulled apart opening a hole about 1/8" in diameter. These tanks were built in 1982

Old_tank_deformation.jpg

Here is the tank compartment. This is below the seating for the dinette on the port side of the boat. That grey framing was screwed in a little to the left of where it's sitting now, making the tank pretty centered in the whole comparment making it useless for anything else even though it was only tanking about 60% of the whole space.

Old_tank_compartment.jpg

[km1125]

I put some new framing together for the new tank. The new tank is a little narrower and a little longer than the original.

tank_framing.jpg

Here I'm dry fitting the new tank in the framing to make sure my measurements were correct:

Tank_framing_dry_fit.jpg

Here I'm prepping the new parts with some bilge paint. The larger part I was going to use as a partition in the space as the tank doesn't take up all the room, but I'm rethinking just how I'm going to do that now.

painting_the_parts.jpg

Here's what the new compartment looks like now. I really probably didn't need to put those parts up on the bulkhead, but they were some pieces I had and and the straps will fit in the gaps between them. You can also see the new holes for the hoses too, which are moved over several inches from the old hoses.

New_compartment.jpg

[km1125]

The new tank came with 4 embedded sensors for a tank monitor system. Since these would be up against the bulkhead when it's installed, I ran some wires to them in case they might be used at a later time. I'm going to use a different tank monitor system (see below), so these might never actually be used.

Tank_monitor_wiring.jpg

Here are the actual sensors that I'm using. This reads through the tank using capacitance between these two strips.

Tank_monitor_sensors.jpg

[km1125]

Here is the new tank in place. I was able to re-use the old strapping that was on the old tank.

New_tank_in_place.jpg

Here's a cool looking pic of the tank. Probably don't want this kind of lighting after the tank is in use though

cool_tank_pic.jpg

[km1125]

This door used to be just a dummy panel screwed in place to look like a door on the other side of the dinette. There was no reason for it to open before, as the waste tank was right behind it. I took off the angles that held it in place and put some hinges and a handle on it to match the door on the other side of the dinette. I am thinking of boxing in the tank with some panels but that will leave two rather large storage areas for things like spare parts or tools.

Here's a picture of the door closed:

Door_closed.jpg

Here's one with the door open. It came in handy this week as I need to connect the wires to the tank monitor system and didn't have to take the top apart again. You can see all the extra space in there.

Door_open.jpg

[Midnightsun]

Great work, love it when one takes the time to do it right.

Both my tanks have vacuum relief valves on them from the factory. Not that it is required but just adds additional protection against blocked vent or over powerful pumpout units and now is the time to do it before the tank sees it first use. Heck, did not even know this existed until I saw them on my tanks and researched it. https://www.dometic.com/en-us/us/produc ... er-_-25365

[Grafunkus]

Love the access door.