What to look for in GRP boats after 25+ years

Discussion in 'Fiberglass and Composite Boat Building' started by Vulkyn, Nov 6, 2013.

  1. Vulkyn
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    Vulkyn Senior Member

    Water will migrate into fiberglass over time (say 25 years!) but what would be the tell tale signs one would need to look at ?

    Learning about building fiberglass is one thing, reviewing an older boat is a completely different ball game. We don't have marine investigators (i know its a nightmare !) so you tend to have to learn on the fly !
     
  2. michael pierzga
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    michael pierzga Senior Member

    Grp seems to last forever. I see plenty of 25 year old boats in the shipyard with no problems.

    When you survey a plastic boat you look at all the structure that was added to the fiberglass hull after molding.

    Frames bulkheads engine mounts......

    Plastic boats built with a foam or. balsa core need special attention and a pro should be contacted.
     
  3. Vulkyn
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    Vulkyn Senior Member

    There are no pro's to contact.
    Rotting of core's or water migration is difficult to detect in panel construction but i would not look for any boat like that in Egypt.

    Does GRP lose some of its flexibility with age? Would it start to crack after years of flexing?
     
  4. PAR
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    PAR Yacht Designer/Builder

    GRP doesn't last forever and you can have a host of things wrong after 25 years. A 25 year old boat will be at the end of the "dark years" of production builders, which saw resin and industry changes that caused several issues, including blisters and core delamination.

    This isn't something you'll learn "on the fly", as it's all about experience. The logical route would be to "thump" the hull everywhere. Obvious signs of cracking, delamination, torn tabbing, etc. require additional investigation.
     
  5. michael pierzga
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    michael pierzga Senior Member

    Sure...fiberglass has a life cycle like any other material. If the boat you are looking at is low powered the fiberglass will probably last forever. If the boat is a go fast and has been driven hard it might be dead after 5 years.

    I would stay away from any old high power grp boat.

    Core damage can be tricky to find. Surveyor know were to look. Water enters the core thru poorly installed deck fittings or poorly installed hull fitting.

    These are areas you should inspect.

    A plastic tapping hammer can locate delaminations if you know what the sound should be.
    Good sound...bad sound. Your ear is sensitive
    Visual inspection and first impressions are a good indicator...if the boat looks good it probably is good
     
  6. michael pierzga
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    michael pierzga Senior Member

    Try googling...surveying fiberglass boat. Must be info on the internet
     
  7. Vulkyn
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    Vulkyn Senior Member

    I always do and i did buy a marine survey book as well. However feedback from forums is invaluable .... reading from books is one thing discussing them is something else. Much like reading how to drive and learning to drive, at least when you sit in the car you know what the pedals are for.

    I had a chat with a seller who was telling me who great his boat is, luckily i know some one who works in boat repair in the area and told me that bought ran aground took in water and the engine room was compromised, he had done the repairs himself and he could actually see the engines from under the boat.
    Thats the kind of stuff you deal with on daily bases so you tend to arm yourself as much as you can because honestly there is no way on earth i will let some one else survey a boat for me unless i am absolutely sure i have at least a good idea, if not i would probably drawn along with the boat.
    There are no governing bodies that you can relay on or they make sure things are done properly, there is no history of repairs or ownership either.

    And the examples around me are frequent enough to scare the c#$P out of me ... 5 boats sank so far that i was directly aware off .....
     
  8. FMS
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    FMS Senior Member

    It's not uncommon to see a few shallow stress cracks in the gelcoat of a 25 year old boat. These are common around bends and sharp corners. Larger areas of cracking are more of a problem.

    Examine all wood components: transom, stringers, bulkheads, cockpit sole in that order.

    When the boat is out of the water remove the drain plug. Often the drain tube doesn't go all the way thru the transom and you can feel the plywood transom core there to determine if it's been sealed and if there is any softness.

    Often screws used to attach speedometers, transducers, hoses, wires, swim platform brackets, trim tab screws, etc. below the waterline are neglected and allow water into the transom after 20 years. Caulk fails or a screw is removed without filling the hole at all. This also happens on stringers and bulkheads low in the bilge.

    Also look for any delamination of the fiberglass skins and tabbing on wood components, anywhere wood edges are exposed, spongy cockpit sole, open screw holes, and follow any cracks to figure out why it's cracking there.
     
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  9. TANSL
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    TANSL Senior Member

    On ships built today, it is difficult to find but a boat so old could have osmosis issues.
     
  10. Vulkyn
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    Vulkyn Senior Member

    Thanks FMS, do engine mountings in particular need extra attention due to the vibration ?
    Semi displacement hauls are not usually subject to heavy conditions as a planning haul would be.

    Electric wiring and engine would seem an issue as well, even at normal wear and tear rate at 28 years i am sure parts would need to be changed.
     
  11. michael pierzga
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    michael pierzga Senior Member

    The engine mounting structure is not grp, it is a composite of materiel, typically plywood or foam core with steel plates imbeded, then encapsulated in glass fiber and secondary bonded to the hull

    Water, oil intrusion into the stringer, engine mount may cause problems.

    The area were the rudder pierces the hull needs attention, internal fuel tanks need attention, hull to deck joints need attention, trim tab instalations need attention

    Surveying any boat is rather simple when you know how it was assembled.

    Again...if the boat is clean and well kept... the systems function, the bilge is clean, the engine is clean, there are no rustbleeds down the grp topsides...then the boat is probably OK

    Concerning osmosis...nermally you can see the gelcoat bubbles with your eyes...if you observe this ....then take a closer look. Osmosis can be repaired, it can also be so intense that the hull is no longer suitable for purchase.

    Remeber that used boats are hard to sell...never pay a high price, always assume that you will need to invest in upgrading and repairing age related wear and tear.

    Locally a small motorboat was listed with the yacht brokers for 35 thousand...a mate of mine just bought it for 18 thousand. Good boat, needs a refresh and some new fittings.
     
  12. Vulkyn
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    Vulkyn Senior Member

  13. FMS
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    FMS Senior Member

    The advice on checking the fuel tank is good. Tanks in the 1980's were often foamed in and the foam can become water logged and hold moisture alongside the tank causing corrosion. Usually there is an access panel to inspect the top of the tank and the ease of removal should it be required ever.
     
  14. Vulkyn
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    Vulkyn Senior Member

    Its hard to imagine boats that old still in good condition, i mean 28 years is a long time !!
    For me the normal scenario would be a boat full of problems until proven otherwise but this particular brand (Birchwood) seems to hold considerably high value for a boat its size and age specially in the UK suggesting there must be something behind it.

    I have found a friends in Volvo marine division and fiberglass repair, so when i finished with all my research i will go have a look at the boat armed with a million questions, places to look at and area's to investigate.
    Worst thing that comes out of it is a really good experience :)

    I have to say though i am very found of the boat and its design ..... (Birchwood commodore 31)

    [​IMG]
     

  15. Vulkyn
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    Vulkyn Senior Member

    I met with the owner yesterday. Interesting fellow, gave me a run down on how the boat is and the problems / breakdowns he faced.
    At least he was not sugar coating the deal !
    engine overheated once because of wrong installation of the belt that control the water pump.
    The boat also was pushed aground by the waves, no damage to the hull but the rudder and the shaft holder broke. Both repaired now.
    He has a smaller diameter propeller installed, he could not find the right size after the incident. He says he lost around 3-5 knots with the smaller propeller.

    Wiring is in good condition new batteries, gauges and dynamo changed recently after positive / negative mix up in battery installation by a technician (welcome to Egypt!).
    New water tank installed, i need to buy a generator as everything runs from main engine.

    Need hull paint, new anti foil coat, interior will require some work.
    He removed the floor and replaced them with fiberglass / sound sealing the engine comportment.

    Engine is loud no muffler installed (common problem with this model) he has built a muffler and has not installed it yet.

    I have agreed with him to take a trip to see the boat and take a tour with it so i can get more details.
     
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