Holding tank fitting

[jddevel]

In an ideal world I`d like to fit my Dometic holding tank partly below finished floor level. In other words not on the hull base but not far off. What problems do the forum members see in that idea please?

[mrsmelly]

In an ideal world I`d like to fit my Dometic holding tank partly below finished floor level. In other words not on the hull base but not far off. What problems do the forum members see in that idea please?

 

No problem at all. Many boats have them in such a location.

 

Tim

[Chewbacka]

In an ideal world I`d like to fit my Dometic holding tank partly below finished floor level. In other words not on the hull base but not far off. What problems do the forum members see in that idea please?

Only concern I would have is the frame being able to take the weight and to ensure the frame load onto the hull is spread over a big enough area, by which I mean no thin legs bearing on a fibreglass hull. Steel narrowboat is no problem.

[Arthur Brown]

As above ^^^^^ All depends on the material of the hull and the position of the frames. Do not ask a GRP hull to take point loads or even linear loads where you can avoid them. Loads to be carried by a GRP hull need to be spread over an area. Steel boats will take a point load better.

[jddevel]

Thank you all. It`s a narrow boat 10mm base plate. I had hoped to fit the tank between the ribs. As it would

substitute the ballast in the chosen location is this a problem. Obviously it would have to be kept of the

actual steel and secured. How is the question?

[Chewbacka]

Thank you all. It`s a narrow boat 10mm base plate. I had hoped to fit the tank between the ribs. As it would

substitute the ballast in the chosen location is this a problem. Obviously it would have to be kept of the

actual steel and secured. How is the question?

If it is a polymer tank (plastic) it is best placed on a flat strong surface or over time there is a danger of it sagging into the unsupported areas.

Using it in place of ballast will make the boat a bit light when it is empty - depending on the size of the tank of course.

[OldGoat]

If it's any help, I have two tanks (two loos) made out of PolyProp (I think) made to fit between the bearers and thus sit on the base plate. They've been fine for 16 years - apart from the pong, for which I now have a solution.

Easy to fit and possibly refit - if that's eve needed and has the advantage of extra capacity.

[jddevel]

Thanks "Old Goat" that's reassuring. It`s a Dometic tank. 42 litres and PolyProp with carbon filter.It`s going to be installed amid ship and athwart the hull so hopefully lessening the effect of varying content. The important thing at this stage is how to secure and I assume not directly on the base plate?

[PaddingtonBear]

I read your title as holding tank FILLING

[OldGoat]

jddevel, on 02 Nov 2016 - 8:47 PM, said:

Thanks "Old Goat" that's reassuring. It`s a Dometic tank. 42 litres and PolyProp with carbon filter.It`s going to be installed amid ship and athwart the hull so hopefully lessening the effect of varying content. The important thing at this stage is how to secure and I assume not directly on the base plate?

 

No, mine does sit on the base plate - I can't remember whether I put some simple barrier (?roofing felt) twixt it and the steel. Being a new boat the steel was clean with no blemishes. The base of the tank was quite thick, 10mm ?

I had the tanks made to fit exactly between the floor bearers (my builder of the 'old school' variety had bearers at 2ft centres. The joys of having a hull built to my own specifications and the builder then making allowances for my inexperience.....)

The tanks aren't fixed - other than being constrained by wall and floor fixings.

[Phoenix_V]

42 litres is a bit small unless you moor next to the pump out

[jddevel]

Sorry-an age thing. Meant 42 gals!!! Fits neatly between the ribs/floor bearers so will find something suitable for it to rest on and "Go for it" Thanks all.