Sir Percy Posted May 10, 2014 Report Posted May 10, 2014 On excavating down to the bottom of my boat - having taken up the floorboards and removed the ballast (concrete paving slabs), I then had to peel away a nasty, sticky mess of roofing felt. I can understand that it was there to protect the metal against water, but it hadn't - so also had to remove scale rust. Why roofing felt? This isn't a load-bearing material. Should the ballast have been laid differently? Are there any alternatives - like Butyl pond liner? Thanks for looking, appreciate any responses. Bear with me if I need explanation - newbie.
RLWP Posted May 10, 2014 Report Posted May 10, 2014 It's to protect the baseplate from the slabs shuffling about Richard
Ex- Member Posted May 10, 2014 Report Posted May 10, 2014 (edited) On excavating down to the bottom of my boat - having taken up the floorboards and removed the ballast (concrete paving slabs), I then had to peel away a nasty, sticky mess of roofing felt. I can understand that it was there to protect the metal against water, but it hadn't - so also had to remove scale rust. Why roofing felt? This isn't a load-bearing material. Should the ballast have been laid differently? Are there any alternatives - like Butyl pond liner? Thanks for looking, appreciate any responses. Bear with me if I need explanation - newbie. Yeah, ends up a right mess in most cases and if water does get to the bilges it will end up getting trapped between the felt and ballast. When we ballasted all the 2 x 2 slabs were laid on strips of solid plastic, (offcut strips from double glazing) These keep the ballast off the base plate and a decent air gap between. Should any leakage occur, water will flow easily to the stern and dry out quickly between ballast & base plate. There's also good air flow. We accessed our bilges just last week, first time for 6 years so didn't know what to expect. Happy to see this though. No damp or musty smells either. I always intended to put an accessible hatch in this area but prioritised other things. Might well do so now. Edited May 10, 2014 by Julynian
Neil2 Posted May 10, 2014 Report Posted May 10, 2014 As Richard says it's supposed to stop the ballast scratching the protective paint off the baseplate, but the flip side is should any water get down there it is going to take an age to dry out, if it ever does. I think I'm right in saying that in the days when boats were built with "wet" cabin bilges, the floors had longitudinal L section strips which held the concrete slab ballast clear of the baseplate. This method was still used, and probably is still used in some boats even though all boats now have dry bilges. It seems to me to make a lot of sense though it doesn't work if you are using brick ballast.
OldGoat Posted May 10, 2014 Report Posted May 10, 2014 Funny that, When I built, I used roofing felt (as I didn't know any better) as an alternative to waxoil which seemed nasty and sticky. I didn't know it was a general practice. 'twas several years ago.
John V Posted May 11, 2014 Report Posted May 11, 2014 Like Julynian my ballast is laid on spacers, I didn't have access to plastic spacers at the time and just used 1/2" batten. The ballast itself is mixed steel block and pig iron and after about 15 years all is still fine there although I have had a couple of minor floods due to plumbing problems. The raised ballast allowed a good air flow (aided by a fan heater)to dry the bilges quickly and thoroughly
Keeping Up Posted May 11, 2014 Report Posted May 11, 2014 As Richard says it's supposed to stop the ballast scratching the protective paint off the baseplate, but the flip side is should any water get down there it is going to take an age to dry out, if it ever does. I think I'm right in saying that in the days when boats were built with "wet" cabin bilges, the floors had longitudinal L section strips which held the concrete slab ballast clear of the baseplate. This method was still used, and probably is still used in some boats even though all boats now have dry bilges. It seems to me to make a lot of sense though it doesn't work if you are using brick ballast. My first boat had a wet bilge and the slabs were just laid directly on the baseplate.
Sir Percy Posted May 11, 2014 Author Report Posted May 11, 2014 From what you've all said, I reckon that my best bet is to go with using a protective layer of primer/paint, then plastic spacers on which to lay my ballast, as it's concrete slabs. I'm thinking that time / movement probably caused the old felt layer to fail. Now that the metal is no longer smooth due to the corrosion, a new layer would be more of a potential water trap. Thanks all.
Larryman Posted July 17, 2016 Report Posted July 17, 2016 Hello All, Me and my girlfriend are currently in the same position with our narrowboat that Sir Percy was in back in 2014. Just wandering if anyone could recommend anywhere that we could get some plastic spacers that would work to create this ventilation gap between the bilge and the ballast - have been scouring the interweb and can't really find what we want. Many thanks.
Robbo Posted July 17, 2016 Report Posted July 17, 2016 (edited) You could use rubber instead of plastic, I use cut up rubber mats with the hexagon holes. Like this - http://www.matsgrids.co.uk/rubber-grass-mats/55-grassmats-23mm-thick-100x150cms.html?fo_c=730&fo_k=1c7cc18c16d50223013f84b89dac1b93&fo_s=gplauk&gclid=CLflh-27-s0CFTYW0wodr9ECrw Edited July 17, 2016 by Robbo
Phil Ambrose Posted July 17, 2016 Report Posted July 17, 2016 Or you could use plastic curtain track, comes in a roll and cheap as chips Phil 1
Guest Posted July 17, 2016 Report Posted July 17, 2016 (edited) Some people use the larger "cross shaped" tile spacers. For example http://www.ebay.co.uk/itm/Floor-Wall-Tile-Spacers-1-5-2-3-4-5-8-10mm-Grouting-Tiling-Groat-Rake-/271382113933?var=&hash=item3f2fa26e8d:m:mxdAv-0FJkJJPFFKNXzuHKw Edited July 17, 2016 by Guest
Jess-- Posted July 17, 2016 Report Posted July 17, 2016 Some people use the larger "cross shaped" tile spacers. For example http://www.ebay.co.uk/itm/Floor-Wall-Tile-Spacers-1-5-2-3-4-5-8-10mm-Grouting-Tiling-Groat-Rake-/271382113933?var=&hash=item3f2fa26e8d:m:mxdAv-0FJkJJPFFKNXzuHKw another option I have seen used is the pipe clips for 15mm pipe
dreadnought Posted July 17, 2016 Report Posted July 17, 2016 use an old hosepipe cut into about 3inch lengths, alternatively get hold of some old twin and earth cable and cut that up to use as spacers 1
Ropnersnavy Posted July 17, 2016 Report Posted July 17, 2016 use an old hosepipe cut into about 3inch lengths, alternatively get hold of some old twin and earth cable and cut that up to use as spacers If there is any wet, won't the copper in the cable cause problems.... i.e. dissimilar metals
RLWP Posted July 17, 2016 Report Posted July 17, 2016 If there is any wet, won't the copper in the cable cause problems.... i.e. dissimilar metals No. It isn't in contact with the hull Richard
starman Posted July 18, 2016 Report Posted July 18, 2016 I used those big tile spacers too - cheap, quick and simple. In a few other spots used cut-off pieces of hose. That works too but a bit fiddly over large areas I'd say.
cuthound Posted July 18, 2016 Report Posted July 18, 2016 If there is any wet, won't the copper in the cable cause problems.... i.e. dissimilar metals Yes, it will become a copper/iron battery, but only if the water in the bilge is deep enough to cover the copper. If the two dissimilar metals are kept apart all will be ok, although personally I would use plastic as spacers. See the bit about the statue of liberty in the attached. https://en.m.wikipedia.org/wiki/Galvanic_corrosion
Sir Percy Posted July 18, 2016 Author Report Posted July 18, 2016 (edited) Hello All, Me and my girlfriend are currently in the same position with our narrowboat that Sir Percy was in back in 2014. Just wandering if anyone could recommend anywhere that we could get some plastic spacers that would work to create this ventilation gap between the bilge and the ballast - have been scouring the interweb and can't really find what we want. Many thanks. You might have timed this just right - I don't mean picking up on a thread two years old, I mean we're just now getting some hot, dry weather after a wet summer. I think it was like this when I was looking around for material to go underneath the ballast. What I found was quite a few garden hoses being chucked out by people needing to do a bit of a watering and finding that theirs was old and knackered. Good luck! Gav Edited July 18, 2016 by Sir Percy
swift1894 Posted July 21, 2016 Report Posted July 21, 2016 Old fan belts cut into 1" pieces are excellent spacers. I think rubber is better than plastic, less chance of vibration. Also, waxoyl tends to dry out over time and becomes crusty, any water then gets trapped under the waxoyl and retains the dampness in the bilge. Undesirable.
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