Osmosis Buying Advice

Buying a blistered boat:
It is reasonably common to find boats with blisters, fail to sell once the problem is uncovered during a survey.
One of the reasons for this is the cost of repair. To have a full hull bottom repair with a warranty can cost around $800 (NZ) per m². So on a small yacht, the cost of repair can easily approach half the value of the boat.

One argument is to buy the boat at a reduced price and just live with the blisters. However have the problem quantified by a surveyor experienced in GRP construction before committing to the deal to ensure that the hull has not got other laminate damage.

A blistered boat does not necessarily mean it has a ‘terminal’ condition. There are many blistered hulls still cruising blue water and if a purchase can be made at the right price, and the damage has not gone too far, then this may mean entry to a suitable boat.

Another view is to buy the boat and have the blisters remedied by a reputable yard as finances allow. This gives the new owner the benefit of the repair work.

Just remember, blisters eventually mean money and one day you will want to sell your boat and if it has blisters, it well may limit the number of buyers interested in her and the sale price will be lower.

Examples of damage:

	This large blister on a GRP hull has been opened up to reveal the damaged laminate. Note the dry white glass fibers. This is serious blistering that has caused a localized weak spot in the hull. This boat also had a balsa core which was in danger of becoming rotten.
	The balsa core can be seen in this photo. Darker patches are where water has damaged the core. The damaged balsa was removed and the hull dried before laminate repairs commenced.
	This is a good example of a deep laminate problem on a production yacht. The photo shows a pen knife blade inserted under a loose laminate. The ‘90’ is a chalk mark indicating the moisture reading taken. The pinkish roving is actually a layer of Kevlar®.
	Count the blisters. These are small blisters that if left should not affect the hull strength in the short term. But devalues the boat. In this case the owner opted to repair them with a full bottom gel-coat plane and repair with vinyl-ester resin.
	Rudders are often prone to blistering and filling with water. Even late model production yachts have rudders that blister and this may be because cheaper resin is used in the layup. Water inside a rudder can lead to failure of the webs welds where they join the stock.
	Planed hull with deep laminate blister in centre of frame The dark spot is moisture oozing from the core. Note the dry white glass fibers at the bottom of the photo. This hull had a poor wet out of the laminate during construction.