holding tank sizes

[chubby]

Hello

 

I m looking at taking on the unenviable task of replacing my holding tank . My current one is old and these things don t last forever .

I ve had a mooch on tinternet & found two options but would be grateful if anyone can suggest others .

One is from a firm called ASAP supplies . They sell Vetus tanks . These you must purchase along with a fitting kit & then you need to purchase right angled pipe fittings etc . YOU have to fit these yourself which doesn t strike me as entirely ideal & are in various sizes .

Another option is from a website marinestore.co.uk . This tank is made by a firm called Dometic . It comes with all pipes & connections fitted & tested which is preferable to me . The biggest size it comes in is 137 litres . The Vetus ones go bigger . I d get the 170 litre maybe .

Does anyone have a 137 litre tank ? How often does it need emptying out ? Is this a worthwhile size ? It would be smaller than my current one but thats ok with me unless it needed very frequent emptying which then becomes costly .

Has anyone fitted one of these Vetus tanks , i really don t like the idea of having to drill your own holes to fit the connections etc . But will do if people found it straightforward & reliable .

Alternatively does anyone know whereabouts i could get a holding tank elsewhere ?

 

cheers

[Keeping Up]

It depends what sort of toilet you have. Is it a straightforward dump-through, or a macerator, or vacuum flush? They use different amounts of water. For the latter, the volume of water per flush is usually published in their spec and usually makes up a majority part of the content.

 

Ours is a straight dump-through, and we generally find we need to store up to one gallon (4.5 litres) per person per day. Less if we can make extensive use of on-shore facilities - and always more when we have guests who aren't used to boats. For the two of us therefore our 40 gallon (150 litre) tank which actually has a usable volume of about 35 gallons (130 litres) because it's not a good idea to fill it to the brim, lasts between 2 and 3 weeks.

[chubby]

Cheers

 

I m on the boat by myself & liveaboard . If i can get 5 weeks between empying then thats a price i can live with . The toilet itself is a Tecma macerator type & on the back of the flush button it has a dial to adjust the amount of water used during the flush . Never touched it before so i m uncertain which way to turn the dial , but i do have a manual for it so shall check whats what .

I think 137 litres may be bordering on a little small but i like the idea that this ltank comes ready to fit with all the right angled fittings already in place & tested . Vetus ones are a bit cheaper & go bigger but i just don t like the idea of drilling holes in it & fitting the pipework myself . The 137 litre dometic tank may be smaller but perhaps more reliable .

Also , a bit smaller may work out well because the dometic ones aren t as wide as my current one & therefore the tank should fit more centrally width wise and could help with some ballasting issues i ve got .

so if anyone thinks that 4 -5 weeks is possible between pumpouts if i cut water right down to a minimum then i think i ll look to bite the bullet & shell out . I also try to make good use of shore facilities - The WISE approach ....

Wee In Someone Elses .....

 

cheers

Edited June 10, 2014 by chubby

[p6rob]

What's the capacity or dimensions of your current tank and how long does it last between emptying? All other things being equal, with these figures it should be possible to work out the frequency which either smaller tank would need emptying.

[Robbo]

I tink for 5-6 weeks you'll need a lot more (read 400 litres!).

[nb Innisfree]

We have a polypropylene tank of 580 lts, never allowed it above 3/4 full so in practice that means 430 useful lts. Wouldn't fancy anything less as we like to use plenty of flushing water with our macerator to stop pipes smelling.

 

Polypropylene is east to cut holes in, I used a bi metal saw. All inkets/outlets on top of the tank, just in case

 

We used Stansa Plastic Fabrication near Ipswich 01473 312186. Small firm, make tanks to order, ours is welded 12mm polypropelene, nice and solid. Ten years ago now but they seem to be in business still, cheapest in the UK at the time.

[Alan de Enfield]

Just for comparative purposes

 

Our cassette is 22 litres (say 20 litres) with a very small 'flush' volume and lasts two of us 3 days.

A 137 litre tank at the recommended 3/4 max is 102 litres

 

ie 5x the cassette size so it would last two of us 15 days max.

 

As has been suggested work out the exiting tank volume and how many days that lasts and you an extrapolate for the 137 litre tank.

That will take into account YOUR production volumes, and, YOUR flush cycle.

[chubby]

cheers

 

the current tank is 135 cm long , 64 cm wide & 30 cm high . I can 5 - 6 weeks between pumpouts . The company in Ipswich look like a possibility . I ll call them tomorrow & email them too . When things are custom made though i expect high prices so i ll see what they say . Once things start going up past £400 - £450 i ll have to have a rethink .

The Vetus ones might be a decent option . I ve emailed them too as i cannot fathom how all these pipe fittings connect to it . If driling the holes into the plastics fine as you say , then i think it ll have to be the Vetus rather than the 137 litre Dometic . I called the firm selling them who failed to call back after promising to do so . So i ll see what sort of costs the company in Ipswich come up with & take it from there .

 

cheers again

 

Edit : Cheers Alan . i was typing when u replied . its looking like 137 isn t going to be enough afterall .

Edited June 10, 2014 by chubby

[ChimneyChain]

Would you really want to carry around over 200 ltrs of stale shit??

 

Darren

[KJT]

There's a company called Tek-Tanks who make both standard waste tanks up to 1000 litres capacity or custom build to suit your requirements. They are located down South on the Hampshire/Surrey border.

 

www.tek-tanks.com

 

Ken

[Alan de Enfield]

Chubby - your existing tank is 260 litres

[nb Innisfree]

Would you really want to carry around over 200 ltrs of stale shit??

 

Darren

Is stale shit worse than fresh shit?! Edited June 10, 2014 by nb Innisfree

[ChimneyChain]

Is stale shit worse than fresh shit?!

God yeh!!!

 

Darren

[Barge Maria]

Also look at LeeSan. Tek tanks, as you mention, are very helpful in designing tanks and installations.

[Bod]

Remember what ever size you settle on, it has to get into the boat to be of any use.........

Whats the smallest hole, it would have to pass though? (Door way/side hatch)

 

Bod

[David Mack]

Vetus ones are a bit cheaper

Surely shome mishtake!!

[chubby]

Cheers again

 

Vetus ones appear competitavely priced . Not cheap but less expensive than the Dometic 137 litre tank i was comparing it with .

Tek Tanks look like they re worth following up on . Theyve got one for £225 that holds 192 litres . No idea if this is inclusive of VAT but i doubt it so that becomes £270 . I ll call tomorrow as i can t fathom out how much thier fittings etc cost .

One other thing : I don t really WANT 150 + litres of crap being stored on my boat . I ve got a toilet that works but the holding tanks on its last legs so i need to replace it . if i start with a brand new tank then i can " treat " the contents in such a way as to prevent any grim odours . I could use odorlos or brewers yeast etc to treat the tank .

 

Thanks for all your help . I ll be in touch with some companies tomorrow

 

cheers

[Alan de Enfield]

I don t really WANT 150 + litres of crap being stored on my boat .

 

Then dont !!!

For the price of a tank you could have a proper (cassette) system fitted.

 

 

On your own - empty once a week, have a spare cassette and empty once a fortnight - no paying pump-out fees either

[Keeping Up]

One other thing : I don t really WANT 150 + litres of crap being stored on my boat

 

Why not, if it's sealed in a tank ?

[Woodstock]

We had a brand new tank made in the Midlands. It was made slightly larger than the previous one, but with the connections in exactly the same place as the previous one so we didnt have to change fittings. We've had it a while now and no issues

 

Price was reasonable compared to the standard size ones out there- Heres the link I posted at the time

http://www.canalworld.net/forums/index.php?showtopic=58124&hl=

[nb Innisfree]

Surely the whole point of a holding tank is to hold larger quantities of toilet waste than a cassette system. If the OP doesn't fancy doing that then why is he/she bothering one?

[Paul's Nulife4-2]

Would you really want to carry around over 200 ltrs of stale shit??

 

Darren

It would help to solve your Ballast problem !

[John V]

Would you really want to carry around over 200 ltrs of stale shit??

 

Darren

 

200 litres, that's just a big cassette.....My black tank holds 160 gallons and I have a separate grey tank that holds another 80 gallons.

The grey water gets pumped out at high tide but the black tank has to last until the poo truck comes, or till I can get far enough off shore.

[chubby]

lCheers for the replies folks .

just to clarify that what i meant when i said i dont want 150 litres of crap onboard is that i dont WANT any crap onboard . But its a boat not a house & so therefore i MUST have crap onboard . The whole pumpout v cassette things been done to death .

I have to replace my holding tank as it has unfortunately split . Only slightly & the tanks empty thank goodness having just recently been emptied . So i was seeking opinions on size & manufacturers so i can make a decision about where to buy my new one . Thankyou for your replies as i now understand which sizes are worthwhile & have contacts for sourcing my new one .

Paul . Your comments re ballasting are also relevant and this issue has also crossed my mind . My boat leans left . My current tank ,is under the bed - on the left , & so if i can source a tank that is narrower ( though admittedly smaller ) this will keep the weight of the contents as central as possible & may contribute towards a correction of the boats current slight list .

This is why im looking for manufacturer recommendations so as to increase the options available

 

Cheers

[Paul's Nulife4-2]

I think you're just going to have to play around with moving weights, it's very difficult in not only a shallow area (ie Area between Base plate and Floor) but a Narrow area as well, so good luck with that one, a job I don't envy you've got.