A recent pre purchase survey on a 1985 Princess 35 powered by twin Volvo Penta 165hp diesel engines, showed us that you can buy a ‘lot of boat’ for a budget price
This Princess 35 is an estuary / coastal GRP motor cruiser with twin inboard diesel engines and standard shaft propulsion. The hull design is medium V with chines
This marine survey was carried out at St Olaves Marina. Where earlier this year they upgraded their lifting capability with the addition of a 50 tonne travel lift. Being only 1/2 hour from Breydon Water / Gt Yarmouth, St Olaves Marina now offers a readily accessible lifting service to boat owners and passing yachtsmen
As is usual most boats of this vintage that moor on the Norfolk Broads / inland waterways this Princess being no exception, the underwater surfaces will tend to have osmosis. Interestingly boats moored in salt water will (to a much greater extent) tend to not have osmosis.
All GRP structures immersed in water will absorb water through the gel coat, to what extent this happens is dictated by numerous factors. Water temperature, thickness of gel coat, quality of construction, quality of materials, temperature during build, and salinity of the water all have some bearing on the absorbency of your hull.
Visual evidence of osmotic blistering Associated moisture meter readings
Very simply, the problem is caused by water penetrating the gelcoat and entering the laminated structure. This water takes in solution free chemicals salts and becomes denser than salt water on the outside of the hull. This creates a differential pressure and since water will not compress blisters form on the outer side of the gelcoat
Today the presence of osmosis does not cause great concern. If there are blisters but they are small and not too many they are not likely to have any significant effect on the structural strength.
Other than the above osmosis which is considered relatively minor there were not too many negative factors, and at the price paid the new owner is able to bring this Princess 35 up to top specification and enjoy many more years of top quality cruising
In summary the following items required attention:
Raw water seacock valve security Fuel tank piping conformity
Battery storage Auto bilge pump satisfactory operation
For more information contact European Marine Services Ltd – Marine Surveyors & Consultants Tel : 01603 327 123 www.europeanmarinesurveys.com