Water tank rplacement for 3870 boatworkfl-gctid821400

[boatworkfl]

Recently I discovered why I use so much water, a leaky tank.

I was able to see the major leak area from the port stateroom bilge pump access.

The leak was just under the supply fitting and was about 2 1/2" long on the weld.

I emptied the tank and let the water drain then put 3 large coolers of water on the bow then used a heat gun to dry the area.

I then sanded the seam and used 2 layers epoxy and 2 layers of the sealant that is advertised on TV on a boat bottom, I let it cure and re-filled the tank, still have a slow leak or leaks but doable for now.

I will tear up the floor before I leave Seward, AK and take the measurements.

I intend to build 2 tanks to fit out of Vinyl ester resin and fiberglass and install pads to fit the pipe threads.

After layup I will heat the tanks to 160 to 180 for 6-8 hours to drive off the gasses and that should leave the tanks to be used for water.

I will take photos of the layup and finished product and the installation and post it.

I will try and make the photo's posted so they can be copied.

I need to build a 12' x 16' extension on my shed for a more doable workshop, with a portable air conditioner so I can layup an item with out the heat curing the resin to fast.

I will be leaving AK at the end of August and drive back to Florida.

boatworkfl

[Pcpete]

You must have access to a pretty good size oven. I'm a how can I get the best bang for my buck kind of guy and enjoy building my own whatever I'm working on, but I balance that against the total cost of getting the parts where they need to be. My minor discomfort with your plan is transporting the tanks to Seward in the spring. The territory the new stuff will take up is significant, or, if you are going to freight them up, the risk and cost of that verses, and I'm sure you've done the research, however, buying a semi custom set from one of the manufacturers and having it shipped. If you have a buddy with any kind of a shop or store you may even be able to piggyback on a regular order. I'm thinking pallet or small container.

One of the other guys here did a double poly installation and would be able to give you the tank part numbers and the rest of bill of materials he used.

Just me being me

Pete

[aspen1880]

25 years ago i was heavily into windsurfing. a buddie built his own boards. he had a simple rigid foam box that was large enough to hold a 9-1/2 foot windsurfer. inside were several 40w incand light bulbs. easy to hit temp targets between 100 and 200F by varying venting and bulb sizes. worked awesome! probably about $30 of materials, very simple.

[boatworkfl]

I haul a 5' x 8' x 4' enclosed trailer up to Alaska each year and back, I may be buying a new wider and longer trailer next year, Sams club has these in Florida.

[Cool_Beans]

Interesting, I'll be following along as my tank is knocking on deaths door.

Not to hijack too much, but would it be easier to build in an integral tank? Stringers as the sides, small strip over the keel and you have the bottom of the tank, bulkhead each end and a top? Seal and coat the inside with food grade epoxy? I'm sure I'm over simplifying it, but...

[boatworkfl]

I would need to tear apart a wall and the floor in the port stateroom to build in lace, then there is the issue of curing the vinyl ester resin at 160 to 180 degrees for 6-8 hours to make it safe for potable water.

I also live on the boat in Alaska all summer.

[boatworkfl]

A plywood box or even a small tent will work and a heater.

[Craggles]

I have just gone through this exercise on my 1987 3870 I purchased in January knowing the water tank was had it. Once I warily looked around I used my 5" power saw and cut through the two layers of flooring in the passage for access to the tank. I used a drill, jigsaw and angle grinder to cut the original water tank in half and pulled it out in three pieces. I drew up computer drawings and had two tanks made, dropped the first in the passage access, slid it over and dropped the second tank in. All threaded fittings are accessed under the steps included balance pipes, filler and dual breather pipes. I ended up making the section in the passage at galley level into a storage area, removable steps to allow access to bilge and pumps and to plumb the two plastic food grade tanks. I don't know why but I have trouble uploading photos. I will try again.

We live aboard our boat and my wife's business is on the marina sewing and upholstering so I put the boat back together every afternoon before she got home.

[boatworkfl]

"Pcpete" post=821411 wrote:
You must have access to a pretty good size oven. I'm a how can I get the best bang for my buck kind of guy and enjoy building my own whatever I'm working on, but I balance that against the total cost of getting the parts where they need to be. My minor discomfort with your plan is transporting the tanks to Seward in the spring. The territory the new stuff will take up is significant, or, if you are going to freight them up, the risk and cost of that verses, and I'm sure you've done the research, however, buying a semi custom set from one of the manufacturers and having it shipped. If you have a buddy with any kind of a shop or store you may even be able to piggyback on a regular order. I'm thinking pallet or small container.

One of the other guys here did a double poly installation and would be able to give you the tank part numbers and the rest of bill of materials he used.

Just me being me

Pete

I drive every year from Florida to Seward, AK, I have a 5' x 8' x 36" high enclosed trailer.

For an oven a simple enclosure of thin plywood or 1 1/2" foam will work for an oven, it does not need to be very hot, just enough to bake and cure the resin.

The 2 tanks can be wrapped and mounted on each side of the trailer.

[Woodsea]

You could possibly use your trailer as your "oven". I bet just closing it up and leaving it in the sum would do pretty well in the Florida sun. If not just add a couple of 100 watt incandescent bulbs.

[boatworkfl]

I just returned to Florida yesterday, I will be building an addition to my storage shed, 12' x 16' for a shop.

After the shed is done I will order materials for tunnels, I have orders for 2 sets so far.

Does anyone know if the 4550 has the same size tunnel exit as the 3870?

When I build my new water tanks I will use iso resin then have a vinyl ester liner inside, although iso resin is supposed to be drinking water safe.

I use iso resin on the tunnels, more water proof than GP resin.