I buy 3 gal of interlux Ultra Putting on 2 good coats I have a little left over to use next time

Perhaps the wing keel takes more. I used Micron initially and now use Act I do not believe I have ever used over a gallon for 1 coat. When I did the boat the first time with Micron I used 11/2 gallons. Since the first coat I have never used a full gallon and usually have a small amount left.

For me, 2 gallons is plenty. Using a hard paint, I don't want to build up excessive thickness and I doubt more than 2 coats adds any real benefit.

I use Interlux Fiberglass Bottomkote ACT, an ablative paint. I use about a gallon every season. I've used as much as 2 gallons but the results were the same, half a dozen barnacles and lots of Chesapeake slime. The additional gallon of paint made no difference, and just contributed to paint build up.

I don't know how many gallons it takes; but whenever we have our bottom done, it's 2 coats except on the waterline, it's 3 coats. Of course, this may be due to the warm Florida waters.

When I did bottom job 3 years ago I bought 3 gallons of Horizons to put over a fresh Interprotect barrier coat job. I did a black coat, then a blue coat which was a really ugly bright blue so I mixed the remaining black in the blue and did a 3rd coat which looked nicer. I still had almost a full gallon left over.

Slightly off topic, but this paint is totally unsuitable for freshwater despite what Petit says. The slime buildup on it is just unbelievable and it won't slough off like it will with VC17 as the soft ablative surface is rougher and gives the slime more to adhere to. Had a brisk sail one day topping out at 8 knots, mostly between 7 and 8 knots, checked in the water later that day and it didn't look like anything came off.

Petit tells me for slime you need a dual biocide but none of that is legal in Canada. Hate to do it but might end up going back to VC17, maybe VC17M. I thought having the boat on a mooring this year would help as it moves most of the time but it made no difference at all. I scraped it by hand 3 times this year and it comes back in about two weeks.

So few choices up here for bottom paint, most of what is available in the US of A is not legal up here. Kripes.

[QUOTE=ProfDruhot;19419]I am planning on bottom painting my boat. I have had a local marina do it in the past and I am headed for a marina that doesn't mind me doing it myself. My question is how many gallons will I need?[/QUOTE]

Two gallons. After coating the boat you'll have about 1/2 gallon left. Use this to put additional paint on the leading edges of the bow, keel, and rudder, and just under the boot stripe all around.