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Water Tank
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Michael & Norma Greenwood
16 Posts
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12th January 2019 - 9:52 pm
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I am having a large 171l glassed in water tank cut out that runs the length of the cockpit sole.  It was built in as part of the spec for a transatlantic cruise when the Twister was new c 1980.  Reason being it is too large for my needs and I have never been happy with its potability.  Also I want to be able to inspect and clean the bilges periodically.  I am thinking of replacing it with the 61 litre Vetus plastic tank.  Have any members fitted one underfloor?  Any comments welcome.
Miike
"Wild Rover"

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David Hopkins
151 Posts
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12th January 2019 - 10:10 pm
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My first thought is will it fit? It's quite narrow down there.

Which tank are you considering? I could check the dimensions.

 

Dave

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Michael & Norma Greenwood
16 Posts
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13th January 2019 - 12:09 pm
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Re my post above the length should be "cabin sole" not cockpit.
Mike

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David Hopkins
151 Posts
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13th January 2019 - 1:20 pm
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Measure very carefully before committing as I don't think the ATANK 61ltr will fit. 

Screenshot-2019-01-13-at-14.15.03.pngImage EnlargerScreenshot-2019-01-13-at-14.14.48.pngImage EnlargerScreenshot-2019-01-13-at-14.16.17.pngImage EnlargerScreenshot-2019-01-13-at-14.17.04.pngImage Enlarger

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Peter Mulville
210 Posts
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15th January 2019 - 8:47 pm
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I was saving these pictures for the new website. For glass Twisters, I plan to publish a comprehensive review [which will surely be corrected in due course] of the differences in hulls between various build dates plus details of as many and nooks and crannies in a glass Twister that I can find...or people send me. For example, pictures of engine installations and exhaust systems. Please more pictures like the ones below.

However, if you have the standard moulded in bilge water tank this is what it looks like if cut out...and the replacement. This is from Ron Francis who has carried out a major refit on Blue Velvet...and sent lots of good pictures. I have to tell you that cutting it out is going to be very messy.

I haven't asked the cost of the new tank. Me, I have the glassed in bilge tank. I have taken off the hatches [and replaced them because the 'marine' aluminium on the Henderson hatches isn't that great] and cleaned inside. I'd drink the water on a trip but use bottled water normally and refill the bottles. I also fitted an electric water pump to encourage usage. 

If you are worried about the bugs that lurk a very good biocide is hydrogen peroxide. [H2O2]You can get it on the web or it is used by farmers to sterilise the teats on cows. Why, because it has no smell and leaves no taste when flushed. It decays to water [H2O] plus whatever the spare oxygen atom has attacked. Sadly, the very concentrated version is harder to get now. A good dose [leave for 24 hours] and then well flushed through [use a pump] will sort out a lot. 

Peter

rsz_cabin_sole_no_tank.jpgImage Enlargerrsz_img_6185_1.jpgImage Enlarger

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David Hopkins
151 Posts
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15th January 2019 - 10:19 pm
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Mine is the same and I agree about the Henderson hatches. They are on my list for next year. 

What's funny is the shape doesn't match the ballast shape on the drawings so I'm wondering if (I can't think why) it's a false bottom under the tank. I'm more inclined to think it's not. 

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John MacMullen and Ann Musgrave
154 Posts
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16th January 2019 - 8:56 pm
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Here are my thoughts, and we are talking here of the GRP hulls:

I would suggest that, in the days of Twister building, drawings were for 'guidance' and a lot of finer detail was 'eyeballed' depending on who was doing the job!

Firstly there was an option to have either iron or lead ballast. The latter is certainly nicer, and for the purists, the C of G would be slightly lower and make for a 'stiffer' boat. It also cost a whole lot more and so most boats ended up with the iron. The lead is heavier by volume and therefore allows for a larger FW tank to be formed (around 30 gallons) whilst the iron option (which we have) allows space for about 18 gallons. I don't think that our tank has a false bottom ... it's the GRP over the ballast.

Despite Crionna, and her tank, being 49 years old the water still develops a 'taint' and we tend not to drink it after a while. But we made things a whole lot better by cutting an inspection hatch towards the forward end and fitting a Whale TCL 4 hatch there.  also a new Henderson oval cam action hatch at the after end. This means we can reach all the inside and, originally, give it a seriously thorough clean out. I agree about the raw finish on the Henderson aluminium. We solved that by taking it to a local anodisers who did the business in return for a contribution to the tea fund! There has never been any trace of corrosion on it since fitting years ago. (Use 'Duralac' on the stainless fixing screws). We also made an annular spacer from polypropylene sheet, some 20mm thick. This keeps the hatch up out of any bilge water or any grot which may find its way there on its way from forward to the bilge sump. Lastly we have a second Whale bilge pump mounted in the cabin under the chart table. This has a 1 metre hose extension to its suction which we use to pump out the fresh water tank before refilling or for flushing. 3 minutes is all it takes and we think it was well worth doing.

The stainless tank that Peter shows is indeed a very fine thing. I'm glad it wasn't paid for out of my bank a/c!

Hope this is all helpful  

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Peter Mulville
210 Posts
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8
17th January 2019 - 4:27 pm
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I replaced my aft oval Henderson Hatch [3rd time I've done this on VIVEZA!] on the bilge water tank 2 years ago - and, like John above, I created an oval [with hole in middle] spacer to lift the hatch out of the small sump it sat in. I didn't think of anodizing the hatch [great idea - this is why this forum is most useful] but did apply much expensive paint.

I made the spacer out of 12mm black High Density Polyethene. [HDPE.] A sheet was a few pounds from the web. I'd already bought the Henderson Hatch for some £60.00. As I was making the spacer I realised that I could have fitted it on the underside of the glass fibre top of the water tank using a couple of small stainless steel self tapping screws where it would act as a backing plate. I could then have made a second solid oval 'spacer' - which in fact would be a lid. 

HDPE is easy to work with wood working tools. It takes self tapping screws well. Just drill the standard sized pilot hole. I could have screwed on the HDPE lid, into the backing plate, using the existing holes in the tank top with say, No. 10 self-tappers and saved £60.00. The downside would be that if I wanted to look inside [I have little desire to do so - it could worry me - although last time I looked it was apparently clean] it would take a little longer to remove the screws. An upside is that I'd have a more reliable fitting.

I'd use plenty of polysulphide sealant. I'd probably route a couple of small grooves on the underside of the lid, one inside and one outside of the line of the screws, to hold the sealant. As always, I'd only loosely fasten down until the sealant had set - then harden up.

I might have to replace the bigger forward hatch this year. If so I'll use this technique.

John is absolutely right; it's best to refill an empty tank. If you can, it's a good idea to flush a tank through at the beginning of the season using your chosen biocide...but do empty over winter if out of the water. Beware of frost!

Peter   

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Justin Butler
149 Posts
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17th January 2019 - 7:02 pm
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Just on the subject of taste and health... One of the first things I did on Roquetta was install a water filter. Its push fit (after a fashion), and the whale hand pump can draw water through it with only a little extra effort.ill be upgrading that to an electric pump soon but the process was: removing both inspection hatches, filling the tank and adding one of the proprietary water/tank cleaning agents and letting it slosh around at the mooring for a week, then draining, cleaning and refilling the tank. The tank wasn't spotless. Then I installed a filter (activated charcoal, filters to 1 micron I think I recall).

I changed the filter after I'd got through the first tank of water, but have left the replacement in for over 6 months and have absolute confidence in the quality of the water. I call it 'eau d' kernow spring' for the guests.

I'm only saying because for the cost and inconvenience of cutting the tank out, a 15 quid filter will fix the problem.

Regards,

Justin,

Roquetta

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Robert Plunkett
20 Posts
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10
29th January 2019 - 6:15 pm
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On Alope, she has just the fwd section of the tank remaining, Not looking fed to cutting it out. Does the tank finish just at the heads/ main cabin area? Will be using a multi tool if I can as a grinder with disc would just be a nightmare. A new stainless tank would be great, does anyone have a price?

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John MacMullen and Ann Musgrave
154 Posts
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11
29th January 2019 - 6:29 pm
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Ours stops at about 400mm back from the after bulkhead (Separating the heads from the saloon). I think you'll find that if you do a gentle hammer test you will hear where the tank end is.

As an aside: After a few days of cold weather take a look at the outside of the hull on the first warm day. The ballast area will have remained colder than the rest and you'll see the ballast outlined in condensation on the keel.

John

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Michael & Norma Greenwood
16 Posts
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1st February 2019 - 5:00 pm
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Thank you for your replies which as always on the Twister Assoc site are very informative.  I bit the bullet and my man has removed the tank top after lifting the flooring - quite a task as the tank top was 30mm thick.  I have decided to replace it with a Tek Tanks 600x240x240mm 32 litre off the shelf tank though will have the hatch and plumbing moulded in by them prior to delivery.   I have made a frame to these dimensions and will verify its suitability onboard this weekend.
I attach a photo forward top showing the tank top removed and will post further images as work progresses.

Hello Robert (replyDSC03663a.JPGImage Enlarger above) owner of "Alope" which I knew when she was at Fairlie and Largs and owned by Brian.  My Twister Wild Rover's homeport is Largs YH and currently on the hard there.  Where are you now?

Mike

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Robert Plunkett
20 Posts
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4th February 2019 - 10:44 pm
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Hi Mike, ‘Alope’ is just further up the Clyde, currently out at silvers marine for a bit of a mini refit. When we purchased Alope from Brian & Melanie, they had mentioned the dodgy bladder water tank which has been in for a long time by the looks of it. The old original tank had been partially cut out for some reason. Might have a work colleague make a replacement 316 s/s made if I have the time.

Cheers

Robert

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Michael & Norma Greenwood
16 Posts
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14
8th February 2019 - 8:01 pm
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After giving the tank shape more thought (and funds!) I am thinking of ordering a bespoke food grade 8mm polypropylene 57 litre tank with baffles, hatch and plumbing and has a sloping base to fit the old tank bottom.  Dimensions 570mm length, 240mm x 240mm for'd end 240mm X 400mm aft end.

Robert look foward to seeing "Alope" back on the water.

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Ian Payne
14 Posts
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15
11th April 2019 - 2:22 pm
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Hi all,

 

I have read this thread with great interest because I have been recently considering what to do with Wild Girls water tank (integral to the GRP moulding above the keel ballast). Her tank is in poor condition internally it seems, it may just be very dirty so I will reserve full judgement until a thorough clean has been undertaken.

My first thoughts were to cut the top off, insert a stainless bespoke fabricated unit and glass that into the current tank void as per examples above. Then I considered the feasibility/availability of a highly flexible but tough bladder (not sure what material - maybe latex rubber of sufficient thickness – something food hygiene suitable), that could be tailored to fit the existing shape e.g. welded sections in the rough dimensions of the tank, as this would ensure maximum expansion of the bladder in the void when filled with water. The bladder could be inserted and arranged within the current enclosed tank through existing hatches and then connections made directly to the bladder from the filler, breather and take off pipework. The original tank would then become merely a former to support the bladder when filled. Following on with this thought process I found this on line.

https://www.covac.co.uk/glass-.....stic-tanks

It looks to offer a paintable solution particularly suitable for GRP tanks and claims to meet all the latest food hygiene standards etc. A paint on bladder in effect, other than the original pipe work connections would need to be retained. I’m now thinking remove the top of the existing tank moulding but leaving a small flange around the perimeter. Clean prep and paint the inside of the tank with this stuff then use Peter’s idea of creating a new lid in HDPE mounted on an anodised aluminium/HDPE ring that bolts through and clamps onto the flange left from the original tank top. Potable water and easy cleaning going forward.

The reason for wanting to isolate the inside GRP faces of the existing tank at all, aside from the look of the current mess in there, is because of the perceived risk I have of styrene’s leaching into the water as a result of Osmotic action. I know Twisters are famed for not generally suffering with Osmosis, however when GRP interfaces with fresh water I think the risk increases considerably. I’m a great believer that stainless tanks dispense the best tasting water, but looking for alternatives to cut costs of going down this route and hoping that this solution coupled with a carbon filter will give satisfactory results 

Has anyone tried or know of any previous use of this type of covering? Or any views on the ideas above.

 

Many thanks

Ian

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