Is a bare bottom a good thing?

M

miss ellie

New member
My 2004 22 has never been bottom painted. Apparently the prior owner did not leave it sit in the SC salt water when not using it.
Last month it sustained damage in a storm, consisting of gouges into but not through the bottom gelcoat (...ugh). The repair shop has given me the option of filling and fairing the gouges and (1) re-coating the entire bottom with gelcoat, or (2) re-coating it with a barrier coat and then 2 coats of bottom paint.
This boat sits on a mooring in Maine salt water June 1 to July 31, and Aug 20 to Sept 30. Its power-washed after each haulout and then left on its trailer. In two months there is plenty of barnacle growth, but it blasts off easily.
Depending on who you ask, and what you read, opinions vary on bottom paint versus just washing the bottom frequently, particularly for a trailerable boat. Having looked at all factors, I am firmly sitting on the exact center of the fence.
Anyone able to throw a little wisdom at this problem?
:roll:
 
Gelcoat is sprayed into the mold to start building a boat. It can be sprayed on to repair a boat but I feel better to apply bottom paint. Salt water as well as fresh will grow stuff. Doing a barrier system and bottom paint will prevent barnackles and would be my choice. You're lucky you've found barnackles easy to wash off they can pose real problems to get off
 
Barrier coat and bottom paint or risk osmotic blisters. Always a shame to ruin and nice, fair, smooth hull with bottom paint though.
Had a 35ft racing sailboat a while back, it just had epoxy barrier coat, sanded to 1000 grit, so we put it in the water so see what would happen. It yellowed badly and got some tenacious growth which consisted of little hairs that just seemed to come out of the surface and very hard to remove. This was after less than a month or so. So we put bottom paint on and wet sanded for days.
 
One source suggested that a boat that sits on a trailer is hard on its bottom paint: the paint becomes less effective if allowed to dry out over a month or more, and also, that being soft and ablative, it is easily scraped off on carpeted bunks.
Ghone and Chriscarerra, what's your experience with your boats, if you store on trailers?
 
I don't know that there is a universal better, but there are considerations.

First of all, if you are keeping a boat in the water in a moderate to high fouling location, you pretty much have to go with bottom paint (or haul every week and clean).

The other extreme is a boat that you keep in the garage, take out for a few days from time to time, and that's it. That boat has no need or desire for bottom paint. After all, it is just one more thing to maintain.

In the middle is where there is no "right" answer, however....

1) I would probably never re-gelcoat an entire boat. The original gelcoat is put into the mold first and then the boat built, and that's not quite the same as spraying it. You can spray it on, no question, but....

2) My question is, can they spot repair it? Typically scratches can be somewhat buffed out, and then the worst areas sprayed/re-gelcoated and then buffed. Are they so bad that they have to do the whole boat?

3) There is the difference in that this is below the waterline, so you don't have the same options as you do above it. Above it, there is no question in my mind that I would go back with a good, two-part paint (Awgrip, etc.). But you can't do that below the waterline.

4) For as long as I don't need bottom paint, I prefer a "bare" gelcoat bottom on the boat. So I would be trying hard for #2, if at all feasible.

5) If you do end up painting/barrier coating, then there are paints that will survive being stored out of the water just fine (and others that won't). There is also probably a paint/type that is better/best for your area (paint requirements are fairly regional in nature). So you'd want a combination of the right kind for your area, plus one that can be dry stored without losing effectiveness.

6) Lastly, know that there is a difference (or was, last time I was "into it" which was a few years ago) between using barrier coat as a tie coat (it will make a chemical tie bond with the bottom paint, and actually using it as a barrier coat. Typically the difference is in the millage (thickness) of the barrier product. As a rule of thumb from "those days," two coats is a tie amount, five coats is a barrier coat. You can/should check on the current recommendations, as they do change over time and with product changes, but this at least gives you an awareness of what you might be looking for.

7) Lastly, I have seen barrier/bottom jobs fail, and almost every time it was due to improper preparation, especially the first time over gelcoat. There is mold release wax on the boat (even decades later), and it needs to be properly and methodically removed with something like Interlux 202 and clean rags/right procedure or you can get bonding failure.

Can you post a photo of the scratches/damage? Of course this is all just chatting about it without actually seeing it.
 
If it were me, I would go for two coats of epoxy barrier, followed by a bottom paint that is made to remain effective for periods of time out of the water. We used Micron CSC and found it to be great for a boat that goes on/off the trailer. I would check with boatyards in your area to see what they suggest for paint. The Micron CSC worked fine in the Gulf of Mexico, the PNW, Florida Keys, and fresh water (Hudson River, Erie Canal, Lake Powell, etc).

The paint we used is ablative - stuff may stick, but it comes off easily. "Easily" as compared to no bottom paint. In our home area, the warm water and high salinity means barnacles can stick in 10 days. The bottom paint makes that less of an issue.

I don't understand the reluctance of some regarding bottom paint. It is part of caring for a boat that spends more than just a few days at a time in the water. We used to have a Corsair trimaran that we raced... with bottom paint; we had it sprayed on to get the smoothest surface possible. It wasn't shiny like the original gelcoat, but it was just as smooth.

Jim B.
 
I just had a similar discussion with my son who lives in Olympia Wa. I was mentioning having to paint Carpy's bottom for an extended visit to the PNW which is in our long range plans. He was appalled at the thought. He sails in Puget Sound and advised me to avoid bottom paint at all costs. He races two sailboats in Budd inlet. One stays in the water and one is on a trailer when not racing. His in water boat is scrubbed fairly regularly with a curvy handled brush he has designed and occasionally by a diver. Bottom paint is very expensive and has a limited life. Removing it is a nightmare. It's toxic. Moreover it is a cycle of endless maintenance. And if anything is to be avoided it is a cycle of endless maintianece.
It is similar to staining a treated wood deck. I have a very large area of treated decks at my hillside home. Every flat surface is a wooden deck. Every spring I power wash it all and in my estimation it looks just as well as those who wash, stain and fuss about their decks. I think it might be the same with bottom paint on a boat that is in the water a limited period of time. Regular scrubbing with brushes, hauling and power washing, or some such routine could eliminate a cycle of endless expensive maintenance.

Just my 2 cents

Carpy
 
" Regular scrubbing with brushes, hauling and power washing, or some such routine could eliminate a cycle of endless expensive maintenance. "

Sounds like a lot of work, too much for me. The PNW is a great place to keep a boat in the water. Bottom paint on a relatively slow moving boat lasts a looooong time. If I were racing my sailboat I might have a different opinion but I am happy to have painted. I used the Interprotect epoxy sealer when she was new with a coat of red hard paint on top. After that it has been CSC, two coats every two years. It is a great ablative up here. I do check periodically ( think GoPro) to see if any red is showing. That would indicate time for a extra coat of CSC but so far I have not found the need.

That's easy living to me but I don't trailer.
 
We've used Interlux Micron CSC in our waters and it holds up for multi season immersion and periods of time on the trailer. We're afloat most of the year but there are times when the boat is stored for a couple of months and the paint remains effective. I'd follow Jim's plan. Although Interlux will recommend 4 coats of barrier. The prep work is the hard part like most jobs. But easy to maintain after it's done.
 
If it were me, I'd fill and fair the gouges, make sure the bottom was well cleaned, remove any remaining wax with Interprotect 202 solvent, apply 2 coats Pettit sandless primer (following directions carefully), and then 2-3 coats Pettit Hydrocoat bottom paint (a not-so-nasty water-based ablative).

Minus filling the gouges, this is what I did in 2006. New Moon spends 2-3 months each summer on the water in BC and/or SE Alaska, then 9 months on her trailer. The bottom paint applied in 2006 still completely stops barnacles, though it's about time for a refresher at least along the sides.
 
In New England the water temperature is 70°. When the boat is in the water for about five days at this temperature, you see tiny barnacles start to form on the lower hull. However, we keep our Marinaut in a boat rack valet storage facility. When the boat is removed from the water, they wash and scrub down the lower Hall. It's been four seasons now that we've had her, and the gelcoat looks brand-new. I don't recommend bottom coating a trailer boat. I've been told that bottom painting can reduce the resale value of a boat by as much as 15%. Aside from that, theoretically, the boat should enjoy greater fuel efficiency due to reduced drag. Additionally, the chance for blistering is much less. why do it if you don't have to, along with added maintenance? It's one thing if the boat is sitting in a marine environment with warm water temperatures all the time, but it is quite another thing if the boat is trailered and/or is used in colder waters. Our previous boat was bomb coded, and it really added it to our annual maintenance expense.

Rich
 
C-Nile":2dt622qm said:
Additionally, the chance for blistering [without bottom paint] is much less.
Click to expand...

I completely agree with you in that I don't bottom paint a boat unless I need to, for various reasons (if I need to, then I do, simple as that; however if I don't, I don't). But, that said, I have to disagree with the statement above. It has been awhile since I was current with these things, but here is what I remember (plus links to articles below)

1) The best thing for the fiberglass part of a fiberglass boat is to be out of the water. Ironic, but true (and the opposite of a traditionally planked wooden boat). Fiberglass likes dry. Out of the water is dry. But that can be achieved with or without bottom paint.

2) As I understand blistering, it involves hydrolysis. Basically, the fiberglass (resin) is slightly porous, and some water molecules can pass through that, especially under pressure. So a slight amount of water basically "soaks in" to the boat hull.

3) Then it combines with some water soluble materials that are typically present in a polyester resin layup. This makes the "sweet smelling brown soup" that often comes out of a blister.

4) The problem with the brown soup is that the molecules are larger than the plain water molecules, so they can't get back out the same "pores" they went in by. Hence it forms a blister (bulge) inside the layup.

Older (1960's/1970's) boats often didn't blister although they were made with polyester resin. Some people think this is because they are better/tougher. I'm more inclined to believe a different theory, which is that the "pores" are larger. This means that when the water molecules that got in combine with the water soluble materials in the layup they *can* get back out. So they do and don't form a blister. However, if this keeps happening over a long period of time, the resin could become "starved" and weaken (as parts were essentially washed out), although it doesn't happen instantly, and I imagine many boats are not in the water enough for it to show up as a problem.

I don't believe bottom paint either stops or exacerbates this process though. I would think it was basically neutral from a blistering perspective.

On the other hand, a properly applied barrier coat (of the appropriate millage which at least used to be around five coats) is supposed to block the "entry pores" that let the water in in the first place. If they are successful, that seems like a good thing. If they are not successful, then I don't see how it could really be any worse than the bare hull (on which the water can get in but not back out once it combines with resin). It would just cost money and be a bit heavier.

Again, I have a bare gelcoat bottom and prefer it this way for how I currently boat. So I'm with you on that. I just don't agree that bare gelcoat makes the chances for blistering less than bottom paint does. However it is true that the less a boat is in the water the less chance for blisters, and boats without bottom paint probably don't statistically spend as much time in the water, so I could easily imagine a correlation there (but not a cause).

Here is some reading on the subject if interested. I likely made some mistakes above as I was just typing from my remembered knowledge.

http://www.zahnisers.com/wp-content/upl ... isters.pdf

Has some formatting issues, but otherwise a good read.
http://www.oceannavigator.com/May-June- ... nd-repair/
 
So we see that there are varying suggestions based on where the boat operates, our experience at what has worked for us and lots of logistical considerations.
My decision is to have the bottom barrier-coated with Sea Hawk Tuff-Stuff and bottom painted with Sea Hawk AF-33.
AF-33 is a hybrid ablative/self polishing coating perfect for the way "miss ellie" is used.
I appreciate all you guys noodling through this topic and being part of this decision. Thank you all.
BTW, so far my experience with BoatUS insurance has been outstanding. Great to work with and fair. They accepted the surveyor's report ($$) and I only have to pay my deductible.
Sure wish they would insure my cars!
 
First, I applaud the decision to epoxy the bottom and use bottom paint. We spent 6 weeks in the water in the strait of Georgia, BC this summer and even with bottom paint had some growth on the stern, where the water didn't ablate the paint. And the latitude is about the same as Maine. You can leave Micron CSC on the trailer for a long time.

That said, here's a note about Sea Hawk's parent company: New Nautical Coatings indictment. Shows what happens if you don't get along with the EPA. I know nothing about the paint and so I was curious.

Boris
 
Just a heads-up that when we had our boat bottom painted for the first time last year the yard said they only recommend barrier coats on new boats. The reason, apparently, is that the tiny amounts of moisture in the fiberglass will cause the barrier coat itself to blister.

Maybe some of the fiberglass experts here could explain how to make sure the hull is absolutely dry.
 
I used to think how nice it would be to have one's boat available in the water at one's own dock. After leaving my boat in the water at a rental place for a month in June, I am still scrapping barnacles. Valuable lesson learned. Take the boat out and rinse once in a while. I have heard that bottom paint adds considerable weight. I'll never complain about trailering the boat again. There are advantages.
 
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