1979 Marine Trader 44 Tri-Cabin Holding Tank Replacement

[KnottyGuy]

[FONT=&quot]Hello Everyone,[/FONT]

[FONT=&quot]Recently I discovered the original fiberglass blackwater holding tank in my 1979 Marine Trader 44 is no longer holding waste. My investigations revealed that a long crack, about 14" in length, formed along the tank bottom corner edge. I suspect a small crack started many years ago and grew as time went on. The sediments inside the tank filled the crack as liquids slowly leaked through into the bilge. The most recent pump out must have dislodged a large amount the filler sediment because now the tank can not contain any liquids. [/FONT]

[FONT=&quot]The factory tank which is 30 gallons (39"L x 15"W x 12"H) was installed between the two inner stringers just ahead of the engine room bulkhead and below companionway leading to the V-berth. This past weekend the tank was cut free of its mounts and removed through a 16"W x 26"L hatch in the V-berth floor. Now outside the boat and upon closer examination the tank does not look worthy of repairs.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]I am looking at this now as an opportunity to increase holding capacity to 50 to 60 gallons. But how do I move forward from here. I see three options:[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]Option 1: Drop in two new holding tanks that will dimensionally fit through the 16"W x 26"L hatch in the V-berth floor. Then hydraulically connect them through another hatch in the mid-cabin floor.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]Option 2: Cut a new hatch in the [/FONT][FONT=&quot][FONT=&quot]companionway floor large enough to drop in the new holding tank. My mistake. This is not an option. My sense of space was off. The companionway is offset right of center to make room for the mid cabin. [/FONT][/FONT]
[FONT=&quot][FONT=&quot]
[/FONT][/FONT]
[FONT=&quot][FONT=&quot]Option 3: Remove a segment of bulkhead between inner stringers from the top of the stringers to the bilge. Then slide the new holding tank from the engine room though the new opening.[/FONT][/FONT]
[FONT=&quot][FONT=&quot]
[/FONT][/FONT]
[FONT=&quot][FONT=&quot]All of the above options will require a self to be built above the bilge area to fully and equally support a new polyethylene holding tank.
[/FONT][/FONT][FONT=&quot][FONT=&quot]

[/FONT][/FONT]

[FONT=&quot]Someone has experienced a similar problem and I am asking for help in determining what will be the best solution. Any advice is much appreciated.[/FONT]

 

[Comodave]

I think that option 2 may be the best choice. I wouldn’t want 2 holding tanks, PITA for pump outs. I would cut a hatch in the deck big enough to get the new tank in and enough room to work on it hooking it up. Make the shelf very strong since the weight will be a lot and you don’t want that tank coming adrift. Ronko makes quality tanks and will install the fittings where you specify. They have hundreds of stock tanks to choose from so you probably won’t have to have a custom tank made, expensive. Good luck.

 

[KnottyGuy]

Ninety-Seven people viewed this post and only one person offered advice? No one here replaced a black water holding tank? That's hard to believe. Thank you Comodave for giving your input.

 

[RT Firefly]

Greetings,
Mr. GK. The easiest, simplest and most straight forward approach would be to replace the old tank with a new tank exactly the same size and profile. You've lived with the capacity of the old tank for how long? Change the tank, not your routine.

 

[Redhook98]

As luck would have it, I have a tank that may work for you, out of a 1979 49ft MT RPH. It is my fiberglass gray water tank. Appx 50 gallon capacity, maybe more. Can easily be re-utilized as a black water tank. Great shape, just decided to go with the small pump out box for my shower instead of the large tank. It is almost the exact same looking tank as the black water tank I have installed.