Elevated moisture in hull - Solutions??

Status
Not open for further replies.
R

Rich Kinard

What do you do when the Surveyor reports : "Osmotic blisters and elevated moisture readings were observed on the wetted surface of the bottom." Anyone know good reference sources to learn more about the problem and how to fix it? Thanks much!
 
D

Don Evans

Elevated Hull Water Readings

Any boat that is not water barrier coated (e.g.epoxy coated), and sits in the water will absorb a certain level of water overtime. How the boat responds to this water seperates a well built hull from a problematic one. Did the survey give you specific readings? In various parts of the hull? You should see those numbers and compare values throughout the hull. Were the blisters in the gel coat or deeper in the laminate? What does the surveyor recommend? I would suspect the boat needs to be hauled, dried out and barrier coated. A very important project, and possibly quite costly. If your prepared to do it yourself you can save a lot of money, but you need to set aside a season for drying, sanding and painting.In a boat that large, make no mistake, this is a big project. Today, yards use mechanical peelers to remove the gel coat, exposing the laminate to quicker drying. The deeper blisters are ground out, and epoxy filled, then the entire hull is barrier coated. As an example for cost, I recently read this was done an a 36' cruiser, for a cost of 7K. There are lots of good references for this problem. Don Casey, has written volumes on the subject. Start searching the net as there are many references also. There was a good article last year in Practical Sailor that discussed elevated hull water readings, and its implications. Don
 
R

R.W.Landau

Blisters

I wrote a response but put it in general intrest. Check out "some time off". r.w.landau
 
D

Dave Lewis

Hull Moisture and Osmotic Blisters

Regarding your question of a survey report showing hull moisture and osmotic blisters. There are many good sources of information including the Web but you might want to read the book on repairing blisters by the Gougeon Brothers who manufacture WEST System epoxy products. They have a good text describing the problem and solutions (using their products of course). In short the blisters must be removed by grinding or blasting, and the hull needs to be dried out by storing out of the water (vacuum bagging is an option) for a lengthy period, then fill in the blisters with epoxy and barrier coat the entire bottom.
 
Status
Not open for further replies.