Manatee Bottom Blister Survey

Our 1987 Hull # 69 is due for haulout and soda blasting soon and we where wondering what other Manatee's have experienced or records show for your hulls. We have been in cooler fresh water for the last eight years, prior to that Florida brackish water exposure.
We are planning on using SeaHawk bottom paint and barrier coatings with Petit zinc spray on the prop as we intend to cruise South into salt water soon. Any words of wisdom ( Opinions ) would be appreciated.

I don't think I have any words of wisdom, but hull #39 had an Osprey Composite bottom job in '04 and the recent survey showed no blisters whatsoever.

I have read good reports on Osprey Composite bottom jobs, pricey but guaranteed. Our last trawler was peeled, rebuilt after five months of dryout with West System epoxy, two coats of barrier paint and bottom paint, five years later at sales haulout survey, guess what, BLISTERS. The size and number wasn't a deal breaker but very disapointed that the hull was not blister free.

That's not what you want to hear. ��

Instead of the Petit prop spray I use Rustoleum Cold Galvanizing Compound spray It works very well and costs about $8/can at most hardware stores. It's a very high percentage of zinc.

And that fixes blisters?

Post #5 is in regard to post #1

Well, that was my bad! Sorry. I totally misunderstood that one.

Thanks hmason, but I already ordered the Petit. I hope the spray zinc works, back in 2002 I was able to use the Petit paint on the prop, struts, and rudder that required everything shiny metal, then an etching solution, then white anti-fouling paint. The repair yard was using it on sport fishing boats with success and the yard worker gave me the left overs to do my trawler. Strictly a no no as the stuff had a control # on it and was only authorized for trained licenced repair facilities. What ever was in it worked.

In 2003, when moved from E coast of FL to Lake Travis TX, HEY JUDE had an "agressive" hull sanding & multiple expoxy barrier coats applied. At survey in 2011 no blisters were found, old fresh water bottom paint sanded off & new paint applied. She'll be surveyed again in Nov, hopefully no blisters will be found & salt water bottom paint will be applied.

KASSIE had blisters at survey when we purchased. Surveyor assured us they were not serious. Had hull checked at Osprey Composites. At first it was good news then they did more grinding and said some previous poor repairs were just a cosmetic solution. Long story short...new hull job $26k. We are now two years plus in salt and brackish water non stop. Hauled for cleaning only. Actually just done yesterday and bottom remains perfect. We had four coats of hard paint put on by Osprey, two black then two blue. The black is only showing in a few spots and that was after a year of monthly bottom cleaning when we were in Florida. Will haul for this winter and repainted.
Bob
KASSIE hull #93

Haulout schedule for tommorow so I thought I would check thru the copies of Krogen Manatee builders plans I have for " lift points" but none shown on the plans.
I have a photo of another Manatee in a travel lift to go by, it is lifted about 6" aft of the porthole, and just forward of the salon after bulkhead.

I have seen a diagram for sling positioning but can't find it. Maybe Healhustler has it.

I was told that the slings want to ride over the interior cabin bulkheads. Supposedly that's the strongest points on a boat.

HiDHo said:

Haulout schedule for tommorow so I thought I would check thru the copies of Krogen Manatee builders plans I have for " lift points" but none shown on the plans.
I have a photo of another Manatee in a travel lift to go by, it is lifted about 6" aft of the porthole, and just forward of the salon after bulkhead.

Click to expand...

I might have those plans on my computer, but am not where I can access them right now. Those points are approximately where I marked my hull and should work well on any decently balanced Manatee, the exception being some added obstruction like Phil's (Hey Jude) bilge keels.
On the blister issue, my bottom has had between 3 and 6 dime sized blisters each time I've hauled for paint, only gelcoat deep no big deal and easy fix. I expect that average to continue with similar environment and same bottom paint. Meanwhile, the core still rings good with the hammer test.

Here is ours just hauled for bottom cleaning
Bob
KASSIE

Thanks Larry and Bob, wow 3 to 6 blisters, Larry that would be great, I'll find out soon nowing that blisters are a real crap shoot, with no ryme or reason from hull to hull.

Bill: I should add that I have asked lots of serious yard workers, "Hey, where's all the blisters", and they usually reply, "Oh, they're there alright, maybe not visible, but they're there". These 70's and 80's hulls blister. Keeping them healthy seems to be reliant on the quality and character of bottom coatings, proper application, and how they perform in your particular environment. It's hit or miss. I used Trinidad non-ablative on my two previous hauls and had good success. I switched to the yard's better claims of Sea Hawk on the last one, but I also moved from the east coast, FL to the Gulf coast. I'll learn this winter if I make a mistake.

Haulout this morning gave good news and not so bad news. Good news, the hull beneath the gelcoat is rock solid. The not so good is the gel coat below the waterline has many blister, not a surprise for a 1987. A meeting of the minds concluded that it's time for epoxy barrier coating. The yard machine uses bits of glass and high pressure water. After all the blisters are opened and the bottom paint and gelcoat are removed we will dryout and do barrier coating.
One thing I noticed is the gelcoat has a orange peel texture. I don't know if this normal, I've never seen this type gelcoat before. Also it peels away like thick wall paper, not brittle like most gelcoats I've seen. I guess it could be because of the nearly thirty years exposure to water and bottom paints.

healhustler said:

These 70's and 80's hulls blister. Keeping them healthy seems to be reliant on the quality and character of bottom coatings, proper application, and how they perform in your particular environment. It's hit or miss.

Click to expand...

Yup...My bottom was done by the previous owner in 2006. peeled and 14 coats of Interlux 2000E... $8K job 10 years ago...Nothing evident since...

Could be worse, Bill. How long has it been since the last haul for bottom paint? That gelcoat orange peal sounds like an over-aggressive application to me. More gelcoat doesn't mean a better gelcoat, and that kind of peeling and blistering would be the result, especially if the initial application was too thick.

Hard to believe based on my research that a hull with that many blisters does not have some hydrolysis of the laminates below.

All the top people and yards I researched, discuss very porous gel and breaches through it usually mean hysdrolysis.

My surveyor missed it all with a moisture meter and tapping hammer....be careful.

Hope you are sound.....

8 years fresh water, prior 4 in brackish the rest in salt, most likely spent 15 years in Florida waters, Larry.
Do you know how Krogen built the hulls for the Manatee's ? Seems like orange peel would indicate they used a male plug mould with the gelcoat sprayed on last to end up with orange peel finish.
I will be doing "incantations" to the gods of dry hulls as the paint and gelcoat is removed !

Bottom sand glass blasted today, incantations worked ! A dozen blisters ground out, nothing deeper then about 3/16", previous filling of blisters sound. Next step filling, sanding, then three coats of epoxy barrier paint then anti-fouling paint.
The prop has some minor pitting proable caused by a loose groung connection on the shore power caught 8 years ago during survey and corrected.

Great news!

Great news . Ours has been out for bottom since mid July . Most the time just drying out . I think we had around 20 blisters or so . Also had some glass repair done . Should be back in in a couple weeks . Hope your project goes well .

Thanks, 20 blisters, that's managable Marty. Was your boat built before 1973 ? Much thought that builders got inferior resins after the oil embargo, and that was the start of the blistering problems.
Bill

Epoxy barrier paint going on today, first of three coats, perfect dry warm weather. Hoping to be back in the water in a few more days.
Hope your bottom job is going as well Marty.

Bill: You're going to have one sweet bottom on that boat! Where are you camped out to do the work?

Larry, I did DIY bottom jobs for 25 years of sailing so now that I'm in my " golden years " I'm letting the folks at Angler Marine at Goose Pond Marina, Scottsboro, Al. on the Tennessee river do the job. I'm very happy with the professional job they are doing.
Just notified we will be back in the water tomorrow.
Glad to see Matthew didn't visit your area except for some wind and rain. We will hope it doesn't do a return visit to Florida.