Bottom paint 3 weeks in - what am I looking at here? Lagoon 420 with Sea Hawk Islands 44 Plus...

[rudykruger]

Our boat, a Lagoon 420, was hauled at Bradford Marine in Freeport, Bahamas during December 2019 for bottom paint and other work.

The Islands 44 Plus bottom paint application was a saga. Constant blisters - mainly on the outer starboard hull and keel and to a lesser extent on the port hull - developed in the paint, right up to the day of splashing the boat 2 weeks after painting started. Bradford re-coated the blistered areas several times, sometimes with sanding and a barrier coat, sometimes with sanding only, and sometimes without either sanding or barrier coat. Usually the re-coated areas were done in neat squares as it was rolled on in patches of varying sizes...

So, boat prep probably sub par.

This is the condition of the bottom ~3 weeks after splash. During that time the boat was at a slip facing north, with about equal daily sun on the port vs starboard sides.

Thoughts, comments? Where is this going?

https://www.youtube.com/watch?v=OKGSD_uC9Ug&t=30s

[Peter]

A sad sight, it is obviously not working as "anti" fouling.

Looks like a strip and start again. Been there done that got the t shirt. Wet sanding back to gel-coat is a horrible experience.

What was the age of the paint?
Did you personally inspect the paint when the tins were opened?
Were they stirred correctly?
Did they adhere to the timings between coats? Too soon blisters resulting from solvents in the first coats not escaping. Too long surface too shinny and not re- abraded.

Metal based AF paints copper and tin separate out when left standing. If it is not stirred, using powered mixer and or the lid has been left off the solvents will evaporate leaving a viscous liquid with metal content at the bottom. It is very hard and time consuming to mix in this state. Less knowledgeable folk, professionals included will then thin the paint, but still leave the active metal ingredient undisturbed at the bottom of the tin. During the painting process it is imperative to keep the paint properly stirred even in the tray.

Hard AF paints are still expected to erode in order for the active ingredient to be released adding thinner may interfere with this process meaning once the initial active ingredient is washed off no new will be exposed. Thinned paint will also take longer to go green so adding additional coats too soon will trap un-evaporated solvent - blisters! Use of an incompatible thinner, contamination or poor mixing would also explain the the blistering and or poor adhesion.

FWIW Despite the myths surrounding TBT it is not that effective for sailing yachts, because they remain stationary for long periods and do not sail that fast, where the large ships that it was originally designed for are constantly moving. There are also much better AF paints nowadays that are far less "toxic", knowing that your bottom is very toxic, although in your case probably not, are you happy to scrub it in the water or even swim around it?

[rudykruger]

A sad sight, it is obviously not working as "anti" fouling.

Looks like a strip and start again. Been there done that got the t shirt. Wet sanding back to gel-coat is a horrible experience.

What was the age of the paint?
Did you personally inspect the paint when the tins were opened?
Were they stirred correctly?
Did they adhere to the timings between coats? Too soon blisters resulting from solvents in the first coats not escaping. Too long surface too shinny and not re- abraded.

Metal based AF paints copper and tin separate out when left standing. If it is not stirred, using powered mixer and or the lid has been left off the solvents will evaporate leaving a viscous liquid with metal content at the bottom. It is very hard and time consuming to mix in this state. Less knowledgeable folk, professionals included will then thin the paint, but still leave the active metal ingredient undisturbed at the bottom of the tin. During the painting process it is imperative to keep the paint properly stirred even in the tray.

Hard AF paints are still expected to erode in order for the active ingredient to be released adding thinner may interfere with this process meaning once the initial active ingredient is washed off no new will be exposed. Thinned paint will also take longer to go green so adding additional coats too soon will trap un-evaporated solvent - blisters! Use of an incompatible thinner, contamination or poor mixing would also explain the the blistering and or poor adhesion.

FWIW Despite the myths surrounding TBT it is not that effective for sailing yachts, because they remain stationary for long periods and do not sail that fast, where the large ships that it was originally designed for are constantly moving. There are also much better AF paints nowadays that are far less "toxic", knowing that your bottom is very toxic, although in your case probably not, are you happy to scrub it in the water or even swim around it?

Thanks for the thoughtful reply. In general I did not personally inspect the paint or police stirring and timing (which I don't know enough about in any event - but apparently I really need to learn). Bradford Marine has a reputation as one of the better marine service outfits, but my experience while the boat was at their yard in Freeport was unfortunately sobering.

So, both the blistering during application and the numerous areas where antifoul is clearly not working can potentially be attributed to poor prep - one from incorrect timing and thinning and the other from incorrect mixing? I never saw them thin any paint, but I certainly did see a can opened and after minimal stirring poured into a tray followed by rolling it on.

Point taken about better paints...

[Peter]

Good luck with whatever you decide.

[colemj]

I'm not sure, but it looks like the parts with growth are the repaired parts? They look like rectangle areas of growth. If this is the case, my bet is that they just dumped a bit of paint out of the can to touch up those spots, and did not properly stir the paint. So you got a repair that looked painted, but the paint did not contain any biocide.

Mark