Removing and rebedding windows etc

Tim O

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Hi, just had a prepurchase survey done on a Colvic Countess 33 ketch which I am intending to use as semi-liveaboard come September. One item which has come up is that several windows/hatches have leaks which have had past repairs with silicone.

My ideal solution as advised by surveyor would be to remove, cleanup, and replace with non-setting sealant....start with worst and do over the summer.

Also same problem with some stanchion fittings and chain plates.

How big a job is this as a DIY job? Any advice/costs/time involved much appreciated.
 
Hi, just had a prepurchase survey done on a Colvic Countess 33 ketch which I am intending to use as semi-liveaboard come September. One item which has come up is that several windows/hatches have leaks which have had past repairs with silicone.

My ideal solution as advised by surveyor would be to remove, cleanup, and replace with non-setting sealant....start with worst and do over the summer.

Also same problem with some stanchion fittings and chain plates.

How big a job is this as a DIY job? Any advice/costs/time involved much appreciated.

I assume the windows are in aluminium frames fastened with interscrews, Removal and refitting is two man job. One inside and one outside. You will likely need some/ a good few/ mostly new screws.

If the window units need refurbishing then it may be a pro job although you may be able to DIY with sealing section from Seals Direct


Ease or otherwise of stanchion bases and chain plates depends on the access. It may be two man job but doing what you can reach with windows out may simplify matters.

Check the apparently sound ones too as stainless steel screws passing through the deck etc can suffer from crevice corrosion.

Make sure all screws are well sealed into the deck to prevent water ingress and crevice corrosion in the future


If you stick plastic sheet over window openings dont use parcel tape!
 
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I replaced all six side windows on my deck- saloon ketch at the New Year. Maybe not the best time of year for the job. :D Six out, clean up, fill old holes, drill for new fastenings, and fit new windows in two days. The old ones had been bedded on clear silicon (?). I bedded the new ones on butyl tape. No dramas.
 
I rebedded the windows on a Hunter 272, single-handed, on this tape and they were still watertight after 3 years. I'd also recommend the supplier.
 
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I replaced all six side windows on my deck- saloon ketch at the New Year. Maybe not the best time of year for the job. :D Six out, clean up, fill old holes, drill for new fastenings, and fit new windows in two days. The old ones had been bedded on clear silicon (?). I bedded the new ones on butyl tape. No dramas.

Hi NormanS.....can I just ask why you filled old holes and rolled new?....is that cause you were replacing with completely new windows rather than just resealing?
 
Here are a couple of pics.....best I could pinch from the broker website.....do these look like interscrews?
 

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I have a friend with a colvic countess ketch who's windows leaked like a collander. He and another friend took out all of them (some are difficult), cleaned up re-glazed, re sealed and replaced. It still leaks like a sieve.
I've replaced a few similar windows with good results.
My point is, its not as easy as it looks!
 
Here are a couple of pics.....best I could pinch from the broker website.....do these look like interscrews?

Interscrews appear as screw heads ( usually but not necessarily slotted) on both sides . One side they are just ordinary countersunk or rose head machine screws. The other side they are the interscrews aka barrel nuts which look similar.


A good few years ago I helped a friend remove and refit the windows in his Westerly. The window units themselves did not require rebuilding. Completely satisfactory job.

We needed a lot of new interscrews, which are an uncommon size on old Westerlies and very expensive.
 
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Hi NormanS.....can I just ask why you filled old holes and rolled new?....is that cause you were replacing with completely new windows rather than just resealing?

We were treating ourselves to brand new double glazed windows, oohh!, so although the type of frame and dimensions were the same, the pattern of holes was different. I filled the old holes with Milliput.

The excuse for renewing the windows was that the original bedding between the glass and the frame was breaking down, after 23 years, and leaking, so something had to be done. I had previously renewed the front windows with double glazed units, and there is so much less condensation that I reckoned it was worthwhile.

Incidentally, mine are fastened with self tappers into 10mm GRP.
 
Hadlow Windows in Tonbridge can supply stainless inter screws in differing thread sizes and barrel lengths. They came with plain heads, so I cut screwdriver slots with my dremel.
 
When re bedding don't use Sikaflex or similar - you will never get them off again. Arbomast G is a non setting mastic that is easy to clean off the surplus. Any good builders merchant should have it. Also a lot cheaper, and a cartridge does not 'go off'. Did my windows with it; worked a treat.
 
When re bedding don't use Sikaflex or similar - you will never get them off again. Arbomast G is a non setting mastic that is easy to clean off the surplus. Any good builders merchant should have it. Also a lot cheaper, and a cartridge does not 'go off'. Did my windows with it; worked a treat.

Do you mean Arbomast GP http://www.arbo.co.uk/arbo-sealants/arbomast-gp/ Its only an oil based mastic

The non setting butyl rubber based sealant Arbomast BR is what is usually recommended http://www.arbo.co.uk/arbo-facades/arbomast-br/
 
This is all really helpful everyone, as its giving me the confidence that I can take this job on myself and make a decent job of it.

On the subject of interscrews, am I right in thinking their only real benefit is cosmetic? They sound potentially more trouble than they are worth with their propensity for seizing up on those internal thread,especially if you have to start cutting slots in them with a Dremel as superheat6k suggests?

Im after windows that don't leak, that stay put in heavy seas, but could be taken out reasonably easily if they start leaking again. If straightforward nuts and bolts will do that I'm not massively worried about the cosmetics inside. Dome head nuts have been suggested as one solution there.....in any case I kinda like the industrial look!��
 
I mean countersunk head machine screws rather than proper bolts! My engineer grandfather will be turning in his grave at my loose terminology
 
Interscrews are the best way of doing it. If you assemble them carefully with butyl tape to seal they will be secure and you will not need to take them out for a very long time. You can buy interscrews that do not need modifying - after all they are designed to make life easy for this job.
 
I resealed a leaky window about 6 years ago with Butyl tape. Stocked by most Glaziers,they use on conservatory,s etc. Is non setting and has a 20 year g/tee. Easy to use when you tighten the excess oozes out ,remove with part of a clothes peg
 
A couple of points, firstly +1 for Hadlow Marine and Scapa bedding tape. Secondly use pan head not countersunk bolts into interscrews, countersunk bolts give a much greater risk of cracking a window.
 
Very timely ! I returned from my boat today with a note to rebed one window, did a search to find this discussion is currently live. My window is simply a sheet of tinted acrylic (Hunter Ranger 245) whereas I think OP's is metal framed. Does the advice re butyl or Scapa bedding tape to apply or is there a better alternative? My leaking window has been bodge repaired in the past with just a squeeze of goo which has decayed, so it's time for a proper job!! Thanks in advance .
 
This is all really helpful everyone, as its giving me the confidence that I can take this job on myself and make a decent job of it.

On the subject of interscrews, am I right in thinking their only real benefit is cosmetic? They sound potentially more trouble than they are worth with their propensity for seizing up on those internal thread,especially if you have to start cutting slots in them with a Dremel as superheat6k suggests?

Im after windows that don't leak, that stay put in heavy seas, but could be taken out reasonably easily if they start leaking again. If straightforward nuts and bolts will do that I'm not massively worried about the cosmetics inside. Dome head nuts have been suggested as one solution there.....in any case I kinda like the industrial look!?
Reason I had to cut slots was because my opening forward window would have originally been assembled prior to fitting to the boat when it was built in 1990. The frame had been fitted with a setting mastic, that was not going to release (see note above re not using sikaflex), so all I had was the short stainless stud threads, So I needed something to enable me to spin the interscrews up tight. If you can get to the screw the other side then they will tighten by holding them gently with pliers or very carefully with mole grips.
 
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