Westerly heavy osmosis.

[Akestor]

I got sanding down to gelcoat ( dark green gelcoat-light green is gelshield) . Problem is that i discovered heavy osmosis above keel, with water not being under the gelcoat, but under the outer fiberglass lamination which for somereason was pigmented dark blue. So the vinegar water was trapped between the outer skin and the deeper white colored lamination, and this caused delamination between these layers. I grinded out all wet area and i will relaminate. I guess a sandblast would not have revealled all these as in some cases the outer blue lamination is 5- 8mm thick..
The areas were easily discoverd as they were slightly swollen and could push them with a screwdriver, then grinded until blue lamination was dry and not delaminated from white layer... i read about injecting epoxy in the delaminated area through holes, but then you go blind not knowing where the epoxy got, or were water is still trapped...
Any feeback is very welcomed!

 

[eddystone]

I’m surprised that Westerly used pigmented gel coat below waterline as considered good practice to use clear

 

[anoccasionalyachtsman]

Is it just that area? I don't understand why there seems to be a red layer there but nowhere else. Is it possible that the patch you're working on is an old repair?

 

[Akestor]

Is it just that area? I don't understand why there seems to be a red layer there but nowhere else. Is it possible that the patch you're working on is an old repair?

The blue square is the remaining antiful before sanding. Initially the boat was supported there and moved the support to sand it. You can also see the areas i grinded above the keel,

 

[johnalison]

I’m surprised that Westerly used pigmented gel coat below waterline as considered good practice to use clear

I bought a Mystere in '73 with pigment below the waterline, which was fairly normal at the time, and yes, we did get osmosis, though mildly. In the same yard when we visited during the build they were building Fishers, and these had clear gel below the waterline, so this was a period of transition.

 

[Akestor]

I’m surprised that Westerly used pigmented gel coat below waterline as considered good practice to use clear

Yes, Not only pigmented gelcoat (green), but pigmented outer fiberglass skin also ( blue). The Lloyds certificate shows " work No 032LK". I assume that i am the lucky owner of the 32nd boat made. The LK should mean Longbow Ketch. As it seems , this is one of the elder westerly's (made late 71-start 72) so they might discarded later that way of glassing with a more modern one..( without pigments mayby?). The chop strand mat looks like is layed with a chopper gun than by hand.

 

[Akestor]

I bought a Mystere in '73 with pigment below the waterline, which was fairly normal at the time, and yes, we did get osmosis, though mildly. In the same yard when we visited during the build they were building Fishers, and these had clear gel below the waterline, so this was a period of transition.

Read lately that pigments are helping osmosis development. Wonder why they would use pigment inside the fiberglass

 

[PuffTheMagicDragon]

Not trying to teach how to suck eggs.
Make sure that, after grinding to sound and dry laminate, you repeatedly rinse with copious amounts of fresh water over several days so that all traces of chemical are eliminated before applying the new laminates.

 

[jwilson]

I’m surprised that Westerly used pigmented gel coat below waterline as considered good practice to use clear

I've never owned a Westerly but am fairly confident that the gelcoats used were coloured. I know (and they probably did too) that clear gelcoat is better underwater, but it is cheaper and simpler to use the same coloured gelcoat throughout. Most production builders still do.

 

[johnalison]

I've never owned a Westerly but am fairly confident that the gelcoats used were coloured. I know (and they probably did too) that clear gelcoat is better underwater, but it is cheaper and simpler to use the same coloured gelcoat throughout. Most production builders still do.

I think that improved resins in the '80s and now widespread use of epoxy coating have made the need for omitting pigment less pressing.

 

[anoccasionalyachtsman]

The blue square is the remaining antiful before sanding. Initially the boat was supported there and moved the support to sand it. You can also see the areas i grinded above the keel,

It's obvious now that you've told me!

 

[Bru]

I've never owned a Westerly but am fairly confident that the gelcoats used were coloured. I know (and they probably did too) that clear gelcoat is better underwater, but it is cheaper and simpler to use the same coloured gelcoat throughout. Most production builders still do.

I do own a Westerly and the gelcoat below the waterline is clear

 

[johnalison]

I do own a Westerly and the gelcoat below the waterline is clear

Westerlys were in production for over thirty years, so we need to know the ages of the boats being discussed.

 

[Bru]

Westerlys were in production for over thirty years, so we need to know the ages of the boats being discussed.

1978 in the case of our W33

 

[lw395]

I got sanding down to gelcoat ( dark green gelcoat-light green is gelshield) . Problem is that i discovered heavy osmosis above keel, with water not being under the gelcoat, but under the outer fiberglass lamination which for somereason was pigmented dark blue. So the vinegar water was trapped between the outer skin and the deeper white colored lamination, and this caused delamination between these layers. I grinded out all wet area and i will relaminate. I guess a sandblast would not have revealled all these as in some cases the outer blue lamination is 5- 8mm thick..
The areas were easily discoverd as they were slightly swollen and could push them with a screwdriver, then grinded until blue lamination was dry and not delaminated from white layer... i read about injecting epoxy in the delaminated area through holes, but then you go blind not knowing where the epoxy got, or were water is still trapped...
Any feeback is very welcomed!View attachment 78097

I think I'd be looking for either a surveyor or an expert in the 'osmosis' trade.

 

[JumbleDuck]

I’m surprised that Westerly used pigmented gel coat below waterline as considered good practice to use clear

My '76 Jouster had pigmented below.

 

[Akestor]

Not trying to teach how to suck eggs.
Make sure that, after grinding to sound and dry laminate, you repeatedly rinse with copious amounts of fresh water over several days so that all traces of chemical are eliminated before applying the new laminates.

Sure that's the plan! i started washing yesterday when finished grinding, and planing to glass in about 2 weeks so i can repeat washing and let anything dry. I will glass it slightly lower and then seal it with epoxy putty,.