deck patches

[edmorales]

hello all, i was browsing inside the neigborhood bookstore when i saw some school items on sale, particularly sticky backed vinyl sheets of all colours including transparent ones used for covering textbooks and the sort. $5 for a roll of 75 meters. it also comes in different thickness. i use it now to seal my deck hatches

ooppps! sorry, that's 7.5 meters not 75. i would need a forklift to carry 75!

[Ralph Knowles]

Hi Ed,

This is a salutary tale about using the wrong material for deck patches. It may not apply in your case as I suspect that your yacht has a fully moulded deck with hatches fitting the access cut outs. This tale refers to a Bantock designed 'Kite', which had been built of cedar planks with an 'Image' deck moulding. Bantock boats usually have large cut outs on both the foredecks and the aft decks which are covered by 'sticky'. Unfortunately an unreinforced vynel type material, similar to model aircraft wing material was used. On a cold windy day in Scottish waters there was a small contact at the windward mark where it is suspected that a jib or main boom lightly touched the film patch, which was very taught due to the cold water, and it split so much that within a very few meters, the boat took so much water that it resembled 'Titanic' with the rudder high in the air. Down she went, never to be recovered.

Moral: Don't use film as an unsupported patch, always use 'Dacron' woven sticky. Its as tough as old boots.

Cheers

Ralph

[edmorales]

yup! i agree with you 100%. an unsupported patch will not be rigid enough to handle rough conditions. i use the stickybacked vinyl on top of the normal hatch cover. its hard to notice it on the picture because i'm using the transparent type.
http://groups.msn.com/RCSailing/allican ... otoID=6134
regards
ed

[Chairman]

This is a salutary tale about using the wrong material for deck patches.

I took a deep interest in this subject when I only just managed to recover my boat after one of my patches split. There are a couple more factors to think about.

One is the "tackiness" of the patch material. Some great-looking material is "low tack", intended that it can be re-positioned without too much trouble. For example, I have some transparent book-spine covering material that says (in the packaging small print) "Low tack"...

Another is the effect of exposure, specifically, ultra-violet sunshine, which usually causes plastics to discolour and, more significantly, become brittle and stiff. That was what had happened to my (non-Dacron) patch -- it was a patch that I hardly ever needed to pull off, so it just stayed there getting older and stiffer, until the time a little bump with another object (did I mention this might have been a boat on starboard?) split it end to end.

Final issue is one of temperature and humidity. The lower the temperature, the less sticky the material is, and the more likely there is some microscopic condensation on the deck. I've learned never to rely on a patch put on when temperatures are below about 8 C -- I saw mine just peel itself off while I was jousting at the start line one time, and again just made it back to shore.

[edmorales]

hello all,
then i guess that the material i found on sale would only be advisable to use on southern hemisphere skiff type ioms fitted with hard or rigid hatches