CONTINUOUSWAVE

How much bottom paint is needeed [for an 18-foot Boston Whaler boat]?

What type paint should be used?

ASIDE: I have a 1983 18-foot Boston Whaler boat. It's not in great shape, but the boat is looking better. I have cleaned and I am painting the boat currently. The spider cracking will mostly remain—too much work to cure. I'm ordering a quart of anti-skid for the deck. I have a gallon of two-part poly for the boat. I have painted most of the boat. I ran out of epoxy primer, so I could not finish the interior. The current plan is the use a roller for the primer on the interior. I will then spray the interior walls and trim, I will then mask and roll the anti skip on the main deck and the anti skid sections. The boat has black bottom paint on it, I do not know what type, but it used to live in the water. The boat was a sailboat chaser. She is now a trailer queen. I'm not going to strip the old bottom paint, that would be too much work.

Maybe a quart or half-quart for two coats, but only comes in gallons.

If you are not going to keep the boat in the water you don't need to paint the bottom with expensive antifouling bottom paint. Just try a quart of good exterior house paint. If you use a contrasting color, green for example, it will let you know when another coat is needed.

If the boat will stay in water for a period of more than about a week, the hull bottom should be coated with a protective paint to reduce the penetration of water into the hull.

Check the owner’s manual for advice.

If you do not have an owner’s manual you can read my HTML versions which have been published in the Reference Section for years:

http://continuouswave.com/whaler/reference/manual9-17/

Read the section on the topic of bottom paint:

http://continuouswave.com/whaler/refere ... tml#bottom

If a boat is 17-feet long and 8-feet wide, the bottom would be 8 x 17 = 136-feet-square.

If the bottom has a 15-degree deadrise the the effective width will increase by a factor of 1/cos15 or about three percent. Since the bottom is not square and the immersed area will be significantly less, estimating the area to be covered by just using boat length times beam seems like a reasonable method to estimate the amount of paint needed.

As for the type of anti-fouling paint to use, the best approach is to survey what anti-fouling paint is used in your area. Water salinity, water temperature, water flow, and marine growths all vary, and paints with different properties may be preferred in one location but not in another.

If anti-fouling paint is not necessary then use a tinted white epoxy paint that will just provide a waterproof seal to the hull and match closely the hull gel coat resin hue.

[Repeats his earlier answer to his own question posted a week or two earlier and again suggest to paint the bottom of an 18-foot boat the amount of paint needed will be] about a quart, but that does not matter because [bottom paint] is not sold in quarts but in gallons [and asserts that this answer is] the right answer.


With one gallon you can paint the boat if the the boat is getting her bottom pained separately.

KARLOW— thanks for asking us a question and then giving us the answer. I didn’t realize your post was a quiz.