O'Day 27 Holding Tank

[Clint Abbott]

I would like to install a holding tank in my 1978 O'Day 27 (traditional layout).Unlike in the US, Canada has been very slow to mandate holding tanks in boats, and pump out facilities are few and far between. Thus my boat still has the original direct pump-out head setup.Can anyone with a similar boat tell me where they have located a holding tank? Any suggestions on installation? Size of tanks? Pictures?I have considered putting a 10 gallon tank under the v-berth, and plumbing anti-syphon loops for both the water intake line, and tank to open ocean discharge line. These anti-syphone loops could be installed behind the head on the bulkhead between the v-berth and the head area. I think my best option is to avoid any y-valve and plumb from the head directly to the tank, then have two more fittings on the tank (plus vents of course) - one fitting for the pump out line, the other for a line to the through-hull valve. The other option is to locate the tank under the port settee - but that would require longer hose runs and may be too much weight on the one side.Any comments or suggestions would help.Thanks.

 

[Mike]

Same Boat -- Same Issue

I had the same issue with a '77 27. I installed a 15 gallon flexible holding tank under the v-berth with a y valve -- it's been an excellent solution.

 

[Clint Abbott]

Smell?

Thanks for the feedback.I have heard mixed stories about the flexible tanks - do you notice any smell? What did you prepare for a bed for the tank to sink in/on? Did you use anti-syphon loops?Clint.

 

[guitrain]

I'd like to know more

I have a 25 that I just purchased and the head is missing. There is a hole where it looks like a pump or some sort of hosing went through.Was there ever a holding tank in these boats or were they designed to pump out to the sea?In any case, what would you recommend for such a thing? I was thinking of just a porta-potty.thanksjason

 

[Seth Dixon]

Bladder?

My O25 is just a smaller verion of yours. I have a Manual head with hoses that lead to a bladder under the Vberth. There is some smell that is associated with this set up. Mine is old to say the least, But I plan to replace it with a solid tank in the same location and good hoses.Seth DixonQuiet Time77 Oday 25

 

[Clint Abbott]

Thanks and more thoughts

Thanks for the responses. I have since done more research on tanks. I considered the bladder type - but all sources seem to warn against. I recentely made a few mock up tanks out of cardboard based on stock dimensions of a local supplier and found that a 8 gallon tank would fit (16" x 18" x 8"). This would require me to fibreglass in a plywood shelf. It leaves some room under the tank to access the speed impellor and depth transducer, and enough room above the tank for fittings and to retain the drop in storage bins. An 8" high tank seem perfect as I do not want to cut extra holes in the v-berth and this will fit through the storage bin holes.However, I still am concerned that 8 gallons may be too small!!! Any thoughts??? I have never used a holding tank in a boat of my own, thus have no clue as to volume generated by two people on 2-4 day trips.My lastest thought, is to get a custom made tank, still 8" high and flat on the top and bottom, and the bow end still 16" wide, but the stern end angling to 30" wide. This would make the tank a trapezoid, and increase the volume to ~13 gallons. I have to make a cardboard mock up to see if it I can get this size tank in throught the storage bin hole. If it does fit, I think I will go this option, even though the tank costs alot more than the rectangular stock dimension.Any more thoughts on capacities. For the tank placement in the O'Day 25 - what size was used, the dimensions and shape? Plywood shelfs?Also - I recently purchased the new book from Peggy Hall (the Head Mistress) - but it does not cover these type of issues.Clint.