bottom scraping and beyond

[vtsailor]

Folks,
I'm looking to get a quick "schooling" on bottom work. Let's say you were going to buy a Typhoon that had about 8 years worth of bottom paint on it. What is the process (and tools) needed to scrape it off? Is sanding required in addition to scraping?
What is the most cost effective but "bulletproof" treatment of painting? The boat would be sailed on fresh water, so most likely VC 17 would be applied. (suggestions welcome here too)
Any thoughts on this laborious process would be greatly appreciated!
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Magic flight

[David van den Burgh]

I had good luck with a paint scraper and 80 grit paper on our CD36. You can read about it here: http://www.ariel-cd36.org/projects_bottomwork.htm

[Steve Laume]

I did a Typhoon and the CD-30. A couple of years apart. I found a very sharp chisel with the corners rounded worked the best. If you can find a socket chisel pull out the handle and add a dowel about 18" with a crutch tip on the end. That way you can use two hands and really push the thing. Keep a stone handy to keep the chisel really sharp and a few contour scrapers are handy too. Block the boat up as high as you can so you don't have to bend over as much. Be very happy when you are finished, Steve.

[ray b]

why remove the old paint??
just paint over it and go sailing

[vtsailor]

I could do that, but I'd be falling into the same pattern of neglect that the current owner has exhibited. It's like asking "Why paint your house. Just live in it" At some point maintenance HAS to be done. I can only guess at how much 8 layers of bottom paint weights. Pretty sure it's not an enhancement to the sailing characteristics of the boat.
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Yamaha V-Max Specifications

[Ron M.]

My experience has been that with so many coats of bottom paint it usually scrapes off easily. An assortment of sharp scrapers (chisel type) 4" - 1" did the job for me. The longer the handle the less fatigue, and keep them sharp. It will take some time and effort so do a 2 or 3 foot section at a time then do something else. Wear a mask and gloves as this creates a lot of dust. paint strippers are costly and time consuming.
When you get it down to gel coat - solvent wash , sand with 80 grit , wash again prior to new bottom paint
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M271 engine

[Dan & Pat]

... and don't forget to barrier coat any place where the gelcoat is showing.

I've done a few bottom paint jobs in the last 30 years, and can tell you from experience that it is not the kind of job you want to do over and over. If you don't prepare the surface properly you'll be doing it again. Barrier paint is often a two part - catalyst/paint - product that seals and primes your hull. Gelcoat is usually mixed with and applied with a wax to help free it from the mold during the production of a boat. Even on a 30 year old boat, some of this wax is still present on the very surface of the boat hull so a barrier needs to be established to allow for adhesion of the bottom paint.

I am a big fan of hard bodied ablative paints. Southern waters are known for some powerful creatures and nasty grasses that will live on just about anything. The hard surface paints are less suseptible to these critters. They protect better and last longer. My favorite is stuff called Super Shipbottom can be found at:

www.supershipbottom.com

[David van den Burgh]

... and don't forget to barrier coat any place where the gelcoat is showing.

Not to be contrary - and with respect to DanPat - be sure to do your own research regarding barrier coating to determine if it is the best option for your situation.