Bottom paint necessary?

Have a '77 CHB in Marina in SoCal, never go out. Paint has deteriorated to poor, have been told gelcoat is very thick and not to bother re painting. Have it cleaned monthly.

Greetings,
Welcome aboard. If your diver is fine with scraping and is not requesting painting to make his job easier, leave it the way it is. I don't think anti-foul has anything to do with gelcoat preservation other than your diver may damage the gelcoat since he has to scrape harder to remove growth. My .$02.

What is the diver cost per year vs painting. ?

If you never go out why bother with a diver??

Paint the bottom. The gelcoat will eventually be eaten through to the glass.

If you ever want to sell it - that will be a factor.

Here is what it will look like (from a boat I had surveyed a couple of years ago).

mcrandop said:

Have a '77 CHB in Marina in SoCal, never go out. Paint has deteriorated to poor, have been told gelcoat is very thick and not to bother re painting. Have it cleaned monthly.

Click to expand...

Never go out or seldom go out? If you never go out, why bother with a diver. Just let the barnacles build up like they do on the docks. A 40 year old boat can't be worth much and will probably go to the scrap heap when you are done with it.

Rather than asking people on the Internet, ask your diver if it needs to be painted. Ask other boaters in your marina what they do. Compare the cost of a haulout and bottom paint job to the value of your boat and how much longer you would like to keep it.

Personally, I leave my bottom paint until my diver starts complaining and then have it repainted. You can take that as advice or not.

Menzies:
Are you saying that marine growth can actually cause delamination of a FG hull? The hull shown looks like FG laminated over wood??
Would not have expected any damage other than increased build-up of marine growth.
A past dock neighbor left the bottom of his Marine Trader 44 unpainted for years. It was a real mess when it was hauled but no permanent damage when he finally decided to paint the bottom and go cruising.
Given the comments about going to the junk yard, and the give-away value of the old boat, why bother to do anything??

"Given the comments about going to the junk yard, and the give-away value of the old boat, why bother to do anything??"


If the boat in question has limited value to the owner and never will run on its bottom and that is OK with the marina then you can ignore all of the following:
- bottom
- running gear
- engines
- genset
- etc


If on the other hand the OP wants the option of going out on the boat some day or selling the boat for some reason then minimal maintenance will be a better path. Pay me now or may me later tends to work in this case.
FWIW - Out here where we are in the NE a boat that cannot move under its own power is very often not allowed at local marinas and will deal with problems associated with that condition.

As Chrisjs points out that picture is a glass sheathed wood hull, and lightly sheathed at that. It is not a solid fiberglass hull. The chance that having the hull scraped by a diver frequently over many years might wear away the gel coat is just about 0%.

Chrisjs said:

If you never go out why bother with a diver??

Click to expand...

Yes - a very good point. It will also avoid the inevitable deep scratches in the hull from excessive scraping and the ever increasing fees from cleaning a really fouled hull.

Chrisjs said:

Menzies:
Are you saying that marine growth can actually cause delamination of a FG hull? The hull shown looks like FG laminated over wood??
Would not have expected any damage other than increased build-up of marine growth.
A past dock neighbor left the bottom of his Marine Trader 44 unpainted for years. It was a real mess when it was hauled but no permanent damage when he finally decided to paint the bottom and go cruising.
Given the comments about going to the junk yard, and the give-away value of the old boat, why bother to do anything??

Click to expand...

tadhana said:

As Chrisjs points out that picture is a glass sheathed wood hull, and lightly sheathed at that. It is not a solid fiberglass hull. The chance that having the hull scraped by a diver frequently over many years might wear away the gel coat is just about 0%.

Click to expand...

No, I'm saying that the gelcoat can be eaten through. Not necessarily that the laminate is damaged. Though having the laminate exposed in salt water for years can't be good. Otherwise why would we care about blisters?

2003 Seahorse 53.

From the survey: "Construction is un-cored fiberglass laminate with gelled and cored top sides."

How would the gel coat be eaten through?

If you never leave the marina and don't care about the boat's bottom condition, then you needn't worry about protective bottom paint.

Honestly this is really freaking me out. I would never not bottom paint. Worth of a boat is determined by its worth to the owner. Although my boat is a 1986, the work put into her, restoring her is priceless to me. Why would I not bottom paint? I have a diver go down once a month. I just had it painted a month ago.

Donna said:

Honestly this is really freaking me out. I would never not bottom paint. Worth of a boat is determined by its worth to the owner. Although my boat is a 1986, the work put into her, restoring her is priceless to me. Why would I not bottom paint? I have a diver go down once a month. I just had it painted a month ago.

Click to expand...

I'm with you.

I have no idea for sure that paint helps a bottom, or not

In my boats case, it sat in a Ft Lauderdale canal for 25 years....in warm water.

The owner was a dive instructor, so the bottom was rarely painted but often scraped by students.

When I bought tbe boat, tbe bottom didnt appear poor, but adter some grinding, the gel coat looked like swiss cheese, the mat underneath was dry and could be pulled off by hand, and karge sections of laminate were hydrolyzed.

Cant say why the bottom rotted off, but that was its history...one I will never repeat.

Just how many wood-hulled boat were sunk or given up due to sea worms? More than one can count over the centuries?

I have seen a large plastic sheet pulled under a stored boat with all the edges pulled above the water.

Clorox or similar was dumped in the created pool and nothing grew on the hull.

For a liveaboard a sink discharge would require a piece of hose to go beyond the pool.

I would suggest the hull be spray coated with hot tar its quick and cheap to apply .I know of barges that have been treated this way and it lasts for 5 years

We shouldn't confuse antifouling paint with a barrier coat. A barrier coat protects the fiberglass from osmosis and blistering. Antifouling paint makes it harder for marine growth to adhere to the boat's hull, barrier coat or not.

gaston said:

I would suggest the hull be spray coated with hot tar its quick and cheap to apply .I know of barges that have been treated this way and it lasts for 5 years

Click to expand...

Why???
Is tar that toxic?
Fishermen in Alaska coat their decks w tar. I always just thought in terms of being watertight. But decks on wood boats will grow grass and mould if not maintained.

Studies I have read show some paint does help with preventing water absorption.....doent stop it but it does help slow it.

Paint keeps water from getting to wood quickly so some harder bottom paints do help in my common sense column making the studies seem plausible.....plus personal verifiable experience.

Certainly the thicker and more water migration resistant the coating is, the better the results. A true, properly applied barrier coat is one thing, but a thin, epoxy based paint isnt necessarily nothing.

If you don't bottom paint, you will grow everything ,and when you finally pull the boat it will be so much growth that it will cost you / buyer, alot of money to scrap it off and repair the damage to the hull. If you don't take care of your boat ,you don't deserve to own it.

We bought our boat on saltwater, Naraganssett Bay, and the previous owner spent a pile of money on a very good anti-fouling paint job. I thought to myself we were wasting his expensive bottom job by hauling it out to fresh-water Missouri River. Nope, wasn't a waste at all. The boats in our marina develop a pretty thick slime by the end of the summer, and now we're infected with zebra mussels. That ocean-caliber bottom job on our boat makes a huge difference with the slime and the mussels.

So yes, I'd do a good anti-fouling bottom job no matter where I am or how much we run the boat.