Bottom Questions

[rwappleton]

Survey Says!

[rwappleton]

I mean Survey Says!

[the kuz]

Just to add another data point, in 2004 when we had our repower done on our 1977 36C we also had the built up paint removed (10 -15 coats, several hundred pounds). A tool with a rotating drum about 4 - 6 inches wide and about 2 - 3 inches in diamerter was used. It had 2 or 3 blades and an adjustable guide to control the depth of the cut. The man Tolchester brought in from Rock Hall was so good that he was able to cut the paint thin enough to see through it and still not remove any fiberglass. I sanded around the through hulls, struts and rudders. Boat had just a handful of small (pea to dime sized) blisters, mostly on the keel. Cleaned, filled and sanded them, primed and painted with several coats of ablative. Has held up great.

Don't know if this is what is meant by a "peal" since it did not cut into the glass. I have been told that the resin formula Hatteras used has changed a few times and that some hulls are blister free while many others have cosmetic blister issues. Does anyone know if this is true? One way or the other we got lucky.

Regards, Bob K

[jim rosenthal]

Very good points about thoroughly drying the hull- I was lucky, as the boat was hauled in a dry and windy area and left exposed for several months- a complete winter. Tenting and heat/fan/dehumidifier may be required to get the laminate dry enough to recoat the bottom.

We used ten coats of IP. I think the instructions advise that you build up to a specified thickness, don't they? Whatever number of coats it takes is what you need. I think it's ten mils but I don't recall exactly. The makers know best.

Some boats DO need peeling. Probably somewhere out there is a Hatteras that needs it, but I've never seen one. Most older Hatts, before the vinylester bottoms (I think it's vinyl- I was told it is a product called Glidden Blisterguard) have blisters, and cleaning out, blasting, drying and filling and recoating will be fine for the job.

And, finally, I think peeling is safe when it is done for good indications by someone who really knows what they are doing, has good equipment, and uses it carefully. But most blistered boats do not need peeling, they need drying. And lots of it.

[Boatnut]

I can't speak to this problem on other makes of boats. I haven't owned any other fiberglass boats. But the leading authority on refits of older Hatteras yachts, no less, strongly recommended against peeling the bottom, and I followed his advice. And I've not been sorry. I am not familiar with the laminate schedule on Albins, and I would not presume to give advice on what to do with a blistered Albin.

Did this leading authority happen to give a reason for not peeling the bottom?

When you repair a blister aren't you in effect peeling a whole lot of sections of the bottom? My understanding is the gelcoat is peeled off, which is used to seal the fibergalss. The structural strength is in the heavy matt used.

[jim rosenthal]

Incidentally, RW, my boat looked FAR worse than the photos you put up. From the waterline down, she looked like a leopard. Or a leper. Or something like that.She had more blister than bottom in some areas.

[Fanfare]

I got about 25 years out of my last epoxy bottom seal coat. Then the blisters started returning. Had the bottom peeled about 4-5-6 years ago. Fanfare is currently hauled for her annual bottom paint (Micron 66), zinc renewal, prop check and an insurance survey. Capt. Ned Hickle (surveyor, and HOF group member) has seen the bottom. The rest of his survey will await my arrival in early February, so no report yet. I'm hoping for a good bottom report. The peel took 5 garbage bags of old bottom paint away.

[jim rosenthal]

Yes, he did. The reason is that it is evidently quite difficult to peel to a consistent depth and not cut into the laminate structure and weaken the hull. Most blisters are gelcoat blisters- they don't go below that depth. I agree that if you have blisters which are deep you are going to have to do more- in that case the gelcoat layers may be so compromised that the bottom ought to be peeled and the blisters filled and the outer layer of the bottom renewed with fiberglass cloth and vinylester resin or epoxy. I suspect that many boats have been peeled, or peel jobs recommended, that were not necessary. My source on this also cited boats that have been peeled and relaminated where the repairs came apart with serious damage to the boat.

[rwappleton]

Jim,

In an effort to self educate I came across a nightmare story on Yachtsurveys.com where the peel and repair were done incorrectly.

We will most likely grind them and let the boat sit until mid March which will be two months to dry and then start the repair and barrier process. Bilges will be dried next week by hand and internal heat for about two weeks. Splash moved up to first week in April.

Anyone that thinks we need to wait longer please speak up. Please remember that the humidity will be on the rise by April in Charleston

I am also viewing all the video on the interlux site. Thanks!

Russ

[bobk]

Just to add another data point, in 2004 when we had our repower done on our 1977 36C we also had the built up paint removed (10 -15 coats, several hundred pounds). A tool with a rotating drum about 4 - 6 inches wide and about 2 - 3 inches in diamerter was used. It had 2 or 3 blades and an adjustable guide to control the depth of the cut. The man Tolchester brought in from Rock Hall was so good that he was able to cut the paint thin enough to see through it and still not remove any fiberglass. I sanded around the through hulls, struts and rudders. Boat had just a handful of small (pea to dime sized) blisters, mostly on the keel. Cleaned, filled and sanded them, primed and painted with several coats of ablative. Has held up great.

Don't know if this is what is meant by a "peal" since it did not cut into the glass. I have been told that the resin formula Hatteras used has changed a few times and that some hulls are blister free while many others have cosmetic blister issues. Does anyone know if this is true? One way or the other we got lucky.

Regards, Bob K

There are (or were) two guys in Rock Hall who could peel to exactly the depth needed and virtually no fairing is needed. One of them did my Albin. A peeler is basically a hydraulicly powered, water cooled rotary carbide plane, about 4" as I recall. It uses a washer-like wheel for depth control and can remove as much as needed.... just the paint as Bob K described, or down through the veil mat layer in my case or even deeper in just one pass, if needed. If you have more blister than non-blistered area, I would think this is what you want. And the hull will dry faster because all the laminate is exposed.

I'll expand a bit on the epoxy vs vinyl ester resins for barrier coat, and remember I was a plastics chemist who built fiberglass boats, and researched the blister issue and solutions in the laboratory before I even bought the Albin. Several factors led me to choose vinyl ester. First, the only two guys on the upper Bay who would guarantee their blister repairs were using it (the Rock Hall guys), second was my bad experience with IP, third was the knowledge that epoxies by their chemical nature both absorb and transmit (via diffusion) much more water than vinyl esters, and fourth I discussed the pros and cons with the research manager for epoxy resins at Shell Chemical (a major producer at the time of both epoxy and vinyl esters). This guy was a boater himself and he recommended vinyl ester. Lastly was a tip he gave me that allowed me to thicken the VE resin thixotropically such that I could roll on 25 gallons of 100% resin to the boat in just 3-4 coats vs 7-8 or more as the industry was doing at the time.

The down side is fairing the vinyl ester was a lot harder than with epoxy. But I still recommend vinyl esters and the better boats are being built with it in the hull today.

For anyone contemplating a blister job, you can dry effectively over a northern winter if you keep water from running down the hull. That can be easily done by making a drip edge just above the water line using a good 2" tape like 3M Preservation tape.

Bobk