Sanding/cleaning s glass fibre yacht hull

[chunkolini]

My mate has hauled his yacht out of the water for a winter refurb.
Job 1 clean the hulls A catamaran).
Soda blast? Sand? Scrape?
If blasting how many cfm for the compressor.
Sanding? Belt sander? Disc sander? Hand?
It's quite old and has antifoul paint.
There are quite s few boat types here; any input appreciated.

 

[Barking Mat]

Start off with a high pressure hose.

If the fibre glass is greening, we pass an acid rinse, gloves, goggles, bucket and mop, leave 20 mins, high pressure hose again.

If the antifouling is peeling run round below the water line with a orbital sander. Antifouling is nasty stuff face mask etc.

Repaint.

Obviously checking cutlass bearing, rudder gear, and any Hull fittings are ship shape, etc and winterise.

 

[Keith 66]

How old is she? Grp hulls gelcoat will degrade over time, often a boat will have been machine polished many times & there is a limit to how many times you can get away with it before the glass reinforcement starts grinning through. If its just dirty a good scrub with Jif works wonders. Dark colours fade & chalk much more with dark green & blue being the worst.
As for antifouling, be careful, as said it is nasty stuff. The old TBT stuff cant be sanded off as it clogs the discs instantly, It is horrible stuff that will make you very ill if you breathe dust or fumes in. Copper based is easier to deal with.

 

[500e]

Once washed off an Albin Viggen 24Ft fin & skeg we bought with gun cleaner, 10 coats of AF nothing else would move it, "fibreglass pain stripper it laught at", took forever filthy dirty job the PLine was about 30mm higher when we put it on the water.
Lovely little boat changed it for a Ballad then a Dufor 35

 

[chunkolini]

Has anybody got any thoughts regards soda blasting?

 

[500e]

Seen it done can't remember if they were going to re jelcoat it.
In the back of my mind they were going to tisue and flowcoat as it had surface damage as well as a lot of paint and AF