Moored Boat Sits on Keel During Low Tide

[jsoceanlord]

I have a pure fiberglass 1965 BUCHAN 37 sloop. It's moored and rests on it's keel during low tide. It doesn't really 'tip', but I can't help if the repeated daily stress from sitting on it's keel, in mud, doesn't cause problems. The waterline is about 6-10 inches lower when the boat's sitting on the bottom. Any opinions ?

Also, I scrapped barnecles off along the waterline which also scrapped off gelcoat. Any thoughts for 'touch ups', etc? thanks.

[CSY Man]

It should not hurth the boat if it is well made.

(A junk boat will flex and delaminate, see this article/pics: Boat Review by David Pasoe - Carver 370)

[White Feather]

Move. You have no idea of what is on the bottom under the sand, mud or whatever. It only takes one iron engine head to cut a hole in the keel skin. Move. Well made or not, I would not tollerate my boat sitting on the bottom. Just my opinion.

[Gracias]

Doesn't it bounce around on the bottom in storms? I'd move to deeper water.

[hellosailor]

If that's a full keel (not a fin) I wouldn't worry about sitting on it. That's normal in many areas with sand or mud bottoms and large tidal swings. As long as your rudder and prop are well clear of the bottom you should be OK, but if the rudder or shaft bottoms out--that can get expensive fast.

Gelcoat repair, there are many products on the market. If you simply want protection against moisture getting into the hull, epoxy will do. There are gelcoat repair kits designed to be covered while curing, or not. A fast web search should turn them up but if you've got a local chandlery, they should be able to supply something that meets your demands for cosmetics versus costs.

[White Feather]

That Doesn't make sense. Gelcoat damage can be avoided by moving the boat to someplace deeper. My Cruising Cal had a full keel over a foot wide. Still I would not take a chance on getting it chipped due to hitting or sitting on the bottom when the easiest and simplest precaution is "move the boat to a deeper spot" Not about how easy repairs are. Why damage it in the first place.

Where the gelcoat is already damaged should be repaired BEFORE water can leech in and penetrate the gelcoat and cause damage between the layers and get into the fiberglass inside the gelcoat. Once in the water is costly to repair. It can happen on any boat. A chip down to the fiber layers will leach water in. Haul it and repair it before you have real serious problems.

[Stillraining]

Gel coat is porous..it wont keep water out...if it did there would be no such thing as blisters.

But I agree move the boat if you can...if you cant as long as its on soft mud i wouldn't worry to much about it in calm weather...different story in a storm.

[tallyhorob]

ok the damage was from him, "Also, I scrapped barnecles off along the waterline which also scrapped off gelcoat. Any thoughts for 'touch ups', etc? thanks." not from him sitting on the bottom,

Epoxy is teh fastest for that. I take it you will need the repair to dry fast before the tide comes back in, and if it right on the water line under the barnecles then a perfect match is not as important as getting it sealed back up.

[hellosailor]

If that image links it is from www.pbase.com/sheila/image/82940955 and that's typical in many parts of the world. Nice if you've got the luxury of enough water to float your boat, but in some places "move it to deeper water" simply isn't an option. And hasn't been for hundreds of years, but they deal with it.

[White Feather]

Most boats never see a blister. A friend bought a brand new trawler. It was launched without bottom paint to move it 50 miles. It had to wait for a few months to get hauled out. The entire bottom was blistered. The reason was that when laid up the gelcoat did not set right. The entire bottom had to be West Systemed. My last three boats were older boats. Two had the bottom paint worn off. None of them ever had a blister. Blisters are NOT formed if a boat was cured properly. Just because you have a fiberglass boat you do not have to expect blisters. They are a symptom that something is wrong. The cure is to grind the bottom blisters off and recoat the boat bottom. Marinas thrive on conviencing unwarry boaters that they need the getcoat replaced if you see a few blisters. I looked at a fellows boat that a marina said had to be redone because he had "Excessive Moisture" in the gelcoat as determined by their moisture meter. That's a croc. I have hauled boats that set for years without a blister. Gelcoat does not blister just because it is porous. It is not. If this were true every boat out there would be blistered topside and bottom. My current boat is over 40 years old and does not have a blister anywhere. And my boat has been in the water the whole time. So, wrong though I may be, I'm going out on a limb and saying that gelcoat is not porous and when properly applied will not blister. Of course, I could be wrong. That's just my opinion and I don't have a moisture meter.

[White Feather]

Did you notice that most of the sailboats are twin keeled for just such an event? Most of those are also iron keels. But to each his/her own. jsoceanlord, is this your reason for sitting on the bottom? Do you deal with tides like those in the picture or are you someplace you can move to deeper water?

[Stillraining]

Originally Posted by White Feather

Most boats never see a blister. A friend bought a brand new trawler. It was launched without bottom paint to move it 50 miles. It had to wait for a few months to get hauled out. The entire bottom was blistered. The reason was that when laid up the gelcoat did not set right. The entire bottom had to be West Systemed. My last three boats were older boats. Two had the bottom paint worn off. None of them ever had a blister. Blisters are NOT formed if a boat was cured properly. Just because you have a fiberglass boat you do not have to expect blisters. They are a symptom that something is wrong. The cure is to grind the bottom blisters off and recoat the boat bottom. Marinas thrive on conviencing unwarry boaters that they need the getcoat replaced if you see a few blisters. I looked at a fellows boat that a marina said had to be redone because he had "Excessive Moisture" in the gelcoat as determined by their moisture meter. That's a croc. I have hauled boats that set for years without a blister. Gelcoat does not blister just because it is porous. It is not. If this were true every boat out there would be blistered topside and bottom. My current boat is over 40 years old and does not have a blister anywhere. And my boat has been in the water the whole time. So, wrong though I may be, I'm going out on a limb and saying that gelcoat is not porous and when properly applied will not blister. Of course, I could be wrong. That's just my opinion and I don't have a moisture meter.

You might want to go here and read up on what this guy has to say about it...pretty much the excepted expert on the subject.

Boat Hull Blisters: Blister Repair Failure Part 2 - by David Pascoe, Marine Surveyor

He states even epoxy barrier coating is not 100% water impervious.

But you are correct in saying the main problem is poor wet out and cure...leaving voids for osmosis to take place.

[White Feather]

Very interesting article but it says the same thing. The gelcoat is normally not porus. It has some sort of injury, imporper bonding, improper curing or other factor that has compromised the topcoat allowing water to penetrate the gelcoat to the fiber of the mat. This allows water behind the gelcoat and blisters form between the layers.

Maybe I should have mentioned that I built prototypes and made the molds used on large yachts. From these molds many boats were constructed. We had very strict proceedures that had to be followed to the letter. I won't go into proceedures but it was quite intensive. These boats are top of the line and very expensive. They were custom built for a spicific customer. We had no showroom of finished yachts. They were all delivered as soon as they passed sea trials. We never heard of blistering problems on one of our boats. We had several other yachts come into the yard for gelcoat repairs by our crew. Unless damaged in an accident we never saw one of our yachts return. I worked there a few years. Fiberglass construction is something I know very well. I know that layup is so important that you do not let a hull set for weeks between layers because the laid up layer will over harden and not adhere as well if left for weeks between coats. As I said, if the outer layer of gelcoat is compromised it will allow water to penetrate the hull into the mat. Water behind that coat causes blisters. Most boatyards are employing what I refere to as yardmonkeys who are there to learn at your expense. They screw up and you get to pay again. I don't want some kid learning on my dollars. I know more about hulls and proper proceedures than most boatyards. And deffinately more than a herd of yardmonkeys. Chemical reactions to various coatings can destroy an otherwise good looking job. There is no way to tell a great job from a nightmare until time goes by. Then it's to late, so why would they care if you have to pay again for the same repair? They don't, they have your money and you won't get it back.

David Pascoe knows his fiberglass. As a surveyor he gets to see a lot of wrong way repairs. He also knows the repairs are usually the reason for ongoing returns to a yard. Amature yardmonkeys who are learning will cover up a mistake instead of reporting it to a supervisor and being in trouble for wasting time and materials. That would cost them thier job. So, they cover it up with another grinding and layer of fillers. The mistake will come back to haunt you, not them. His statements about barrier coats being less than 100% impervious to water penetration indicates that there is an underlying reason like the gelcoat having been compromised with chemical intrusion or damage. Properly applied a fiberglass hull will not blister or separate. Also, I was also a marine surveyor until an auto accident crippled me to the point of not being able to crawl through all the very tight places to do a proper survey. And I still can inspect the hull and topsides and find delamination and structurial issues. They are easy, hard is knowing what some yard did to your boat while you were waiting for them to call.

[Stillraining]

My boat did not get a good wet out of the mat...The roving underneath is translucent green and very shinny indicitive of a well done job there....

I could care less if all the gell coat and mat fell off below the water line in one giant piece.....Id barrior coat the whole thing and leave it un-faired.... I might loose a knot of speed but so what. ................wishfull thinking anyway...