Old fibreglass boat

GP14 Sailing Forums Forum Old fibreglass boat

This topic contains 21 replies, has 5 voices, and was last updated by  vortexmike 2 months ago.

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  • #19819

    vortexmike
    Participant

    We have just acquired  an old fibreglass boat to clean up enough for cruising on the Norfolk broads; trying to date it! Number on the sail is 11611, unable to read the makers plate at the stern. There is a plate from “The ship and boat builders National federation” stamped number 25342 ??

    We will need to make some floorboards (thinking 9mm marine ply with some stringers underneath ) and some small repairs to the rubbing strake and possibly the mast step. This looks like a laminated wooden block of some sort with a square cut out for the mast foot; how is this removed ??

    Apart from that I reckon after a good clean Bluebell will be up and running in a few weeks time!

    Any help/advice/guidelines gratefully received

    Thanks

    If anyone has an old spinnaker, pole, bits like that, would be very happy to take them off your hands !

    • This topic was modified 3 months ago by  vortexmike.
  • #19821

    Oliver Shaw
    Moderator

    I think Steve White is the expert on this,  particularly the mast step;     I have forwarded your enquiry.

    I have once,  on a different class of boat,  cleaned up an old moulder’s plate which had been painted over,  and although far from perfect the end result was good enough to be able to read the moulding number.   The problem there was that it had been repeatedly painted over,  so I used repeated applications paint stripper,   applied and gently wiped off with a rag absolutely as soon as it started to attack the paint.    Use industrial gloves!

    I rather doubt whether the number on the SBBNF plate has any  significance within the GP14 Class.

    Congratulations on your acquisition.    Enjoy,  once you have done the work.

     

    Oliver

  • #19823

    warsashod
    Participant

    Hello, I have one that has sail number 11834 which is reasonably close, so may be similar (see pic) and I came to believe it was ca 1974. I haven’t yet found any ID on the hull. Would be nice to know of another person with a boat like mine 🙂

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  • #19827

    Oliver Shaw
    Moderator

    That may perhaps have been a date that I gave you some time ago  (I know that we have been in previous correspondence).    However I have now seen your photo,  showing the stern of the boat.    Since she has no former for a mainsheet horse,  I make her a Mark 3,  not Mark 2.    Thus she is 1977 or later,  that being the date when the Mark 3 was first produced..

    Sorry if I gave you an incorrect date earlier,  based on incomplete information.

     

    Oliver

  • #19830

    sw13644
    Participant

    Oliver and I tag team on helping people with old boats – he specialises in wood and I specialise in old GRP / FRP boats, so he flicked this thread to me as he knows I have some stuff that might help.

    > This looks like a laminated wooden block of some sort with a square cut out for the mast foot; how is this removed ??

    There are two 10mm stainless steel bolts glassed into the hull and pointing upwards. The fabricated laminated wooden shape is fitted over the two bolts, and cinched down. Then, usually, the bolt holes are covered entirely in mastic to make removal difficult and rot less likely. Often the wood on the mast step foot is sufficiently rotten to be carefully nibbled away, revealing the bolt and the nut with washer which should undo cleanly. Then slide the rest of the wood off the embedded bolts. The bolts are precious, as in “I took good care of them so I did not have to find out how to replace them if I broke one off”.

    You may not have enough left to know what the shape looked like, so this is a rough drawing, which at the time came with the measurements A-G, and those measurements have been lost in the many changes to the archives over the years, and I don’t have that vintage of boat any more to be able to remeasure. Hopefully you have enough to be able to work out the measurements.

    Each laminated layer was made from either 18mm ply or three blocks of hardwood planed to 18mm and glued together. Some people drill a hole through the wood to let the square shape drain, and some say that is how the water gets inside the wood. The complex shape that mates the mast foot to the hull needs to be pretty close to spread the load of the mast, so is a craft to achieve and I used a facsimile of carbon paper to find the high spots and hand carved the complex shape until it was a close fit. A good foundation of Sikaflex 291i (other polyurethane bonding materials are available) can be used to cushion the imperfections in hand made manufacture and make a good bed for the mast step.

    Clearly this design is a rot trap, so enjoy working out how to stop the rot from setting in, or accept that the wood is somewhat disposable and pretty much needs replacing every decade or so.

    I hope this helps,

    Steve.

    • This reply was modified 3 months ago by  Oliver Shaw. Reason: Removal of formatting commands
    • This reply was modified 3 months ago by  Oliver Shaw.
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  • #19832

    sw13644
    Participant

    And now the other part of the question – you definitely need floorboards in this style of hull to spread the weight of your feet. The hull was designed with the expectation of floorboards, and missing them will render stress cracks in the hull from the inside from your feet. One day you may crack the hull.

    9mm ply is good, and a cardboard template is a useful tool to get the shape. If you compromise about 2cm off the width, both sides of the floorboards will come out of one piece of standard metric 8×4 ply cut exactly in half. It depends on how long you want them to last as to what quality of ply you use. WBP is OK for this (in my opinion) as small voids are manageable, don’t use indoor ply. The stringers are important, I simply epoxied mine onto the wood with weights to hold the bond until set, without screws or nails, and it all lasted many years. If you make it just right, you can twist a whole half-sheet of floorboard about (with the help of a friend) and fit from the stern, you don’t need to make 4 separate sections.

    As for a finish, you need a rough surface but you will have to kneel on it, so sand can be rough on the knees. A way of making a fluffy surface is to varnish the floorboards (or paint them) and then on the last coat, sprinkle granulated sugar, allow to dry thoroughly and leave in the rain to dissolve the sugar – it leaves a lovely fluffy, non-slip surface that is surprisingly effective.

  • #19836

    Chris
    Participant

    On a boat like this I think I’d use phenolic plywood for the floorboards. No need to coat and already gripped! It’s expensive but will last for ages.

  • #19837

    vortexmike
    Participant

    Thanks for all the info Steve and Oliver. Yesterday gave the hull and cover a good wash to get rid of all the green growths; it already looks like a boat again as opposed to a sad forgotten thing. Hoping to do the spars today but horrible cold rain at the moment!

    Will sit at the computer to source plywood and stuff until it clears later hopefully.

    Thanks

    Mike

  • #19839

    vortexmike
    Participant

    So after your advice the mast step came out quite easily. The top and bottom sections appear to be plywood, the middle section parhaps a piece of mahogany. Some of it definitely neeps replacing !

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  • #19843

    vortexmike
    Participant

    And here is the rubbing strake that needs doing and an interior shot waiting for floorboards

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  • #19847

    Oliver Shaw
    Moderator

    And while we are about it,  those photos identify her as a Mark 2 boat.

     

    Oliver

  • #19899

    vortexmike
    Participant

    So we are making the floorboards; 12mm marine ply. Hoping to cut them to shape into the buoyancy tanks as opposed to a regular 300mm wide rectangle. Do we need stringers on the bottom of the ply and if so what size and shape should these be ? Is there a good reason to just keep a basic rectangle shape ? Should the boards rest on top of the metal tubing front and rear of the cockpit ?

    Does anyone in Norfolk have a similar boat we could maybe look at or some decent photos of floorboards?

    Thank you !!

  • #19900

    sw13644
    Participant

    I believe that there are two reasons for installing stringers underneath the floorboards of a Mk2. Firstly, the floor is curved, and your floorboards are straight, so to remove the resulting pressure where the floorboards touch, and springiness, install stringers. Secondly, a physical barrier at the edge of the floorboard where it does not touch naturally removes the opportunity for something to get underneath and cleat at the very worse possible moment.

    The floorboards need to sit on the hull of the boat, to spread the load of the humans, and not on the aluminium tubes which would be crushed by a concentration of weight.

  • #19909

    vortexmike
    Participant

    One more question I have ! The slot gasket is in tatters and appears to be a folded piece of sail material fixed under the keelband each side of the centreboard slot; I know modern racing boats have this as an essential but is it necessary on ours for cruising ? I remember as a child on our GP number 54 being fascinated looking down into the water through the centreboard casing !

  • #19911

    sw13644
    Participant

    Mike,

    The discussion about whether a centreboard slot gasket is a good idea or not is played out on many forums, just search for ‘reason for centreboard slot gasket’ as a starting place and I’m sure you will soon have many hours of your life consumed by the arguments either way. The Wayfarer forum gives this subject a thorough beating.

    Steve.

  • #19912

    Oliver Shaw
    Moderator

    It might be worth distinguishing between racing and cruising,   but even so the arguments for cruising are not clear cut.

     

    BENEFITS:    probably some protection from getting coarse sand and small pebbles forced up into the slot and jamming the board.    I have twice had the centreboard jammed,  and this in a fairly new boat  –  but the counter argument is that this boat did have a gasket;    and whether the problem would have been more frequent or more severe without the gasket is an unknown question  …

    In other boats,  but I have never noticed it as a problem on GP14s,  there can be a major problem of water spurting up from the top of the centreboard case when punching into a steep head sea and slamming down between the waves,  and a slot gasket does substantially mitigate against this;   but I stress that although I have found this as a problem in my Privateer 20 (before I dealt with it by fitting a gasket,  alongside restricting the slot width) I have never noticed it as a problem in GP14s.

     

    DISADVANTAGES:    none that I can think of,  given that the cost and labour of fitting it is trivial anyway.

     

    Oliver

  • #20017

    vortexmike
    Participant

    I don’t seem to be able to reply on others posts and someone is asking about floorboards.

    Have made ours from 12mm marine ply. Cut to 231 cm long and then the width varies from 33-35 cms. This is shaped to leave a small gap (1 cm approx) by the buoyancy tanks. Have fitted some stringers underneath ( 5 in total) and cut a slot for the catches . When the boards are put in and you press down to do up the catches on each side this seems to hold the boards firmly to the floor which I guess is the desired result ?

    The mast step is rebuilt and in place, the rubbing strake rotten part replaced so nearly there now. New tiller made so just need to put it all together and check everything works.

    The wheels on the trailer that came with the boat are a bit dodgy so have found a place in Wells where I can hire a trailer ( unless someone local can lend me one !!) to move the boat over to Hickling soon. Have now had a message that the club site is closed till further notice but we can still sail on the Broad as long as we keep social distancing……….

    With the weather like it is today just want to get out there now .

     

  • #20019

    Oliver Shaw
    Moderator

     have found a place in Wells where I can hire a trailer ( unless someone local can lend me one !!)

    If you like to make contact with me at [email protected] I may be able to help there;   my godson lives in the Swaffham area,  and he now owns my erstwhile boat,  which is on a good combi-trailer.

    I have no idea whether that is geographically convenient to you  –  Norfolk is arguably the largest county in England  –  and it may or may not be convenient for him.    But if geographically convenient I can at least ask.

     

    Oliver

  • #20034

    vortexmike
    Participant

    I have managed to fit new hubs, bearings and wheels to the trailer along with a new jockey wheel so hopefully that is up and running now!

    One of the RWO cam cleats for the jib sheets refuses to act as it should. I have tried WD40, silicon spray and hot water all to no avail. Ebay is not offering any up so don’t suppose anyone on here has one they would like to pass on ??? Appears to be 40mm between centres of fixing holes .

    Thanks

    Mike

  • #20035

    sw13644
    Participant

    My guess is that the distance between the fixings is 38mm, which is a standard size for cam cleats and the internet is abundant with “cam cleat 38mm” offerings, including from RWO.

  • #20036

    Oliver Shaw
    Moderator

    Depending on the construction of your camcleats you may be able to service them.     Some are amenable to DIY servicing,  but others are not.

    The cams normally rotate around a pair of fixed internal pillars,   but different brands and models differ in what prevents the cams from simply riding up these pillars and lifting off.

    If these internal pillars are rivetted over,  so that even when the securing screws are removed the cams cannot be lifted off the base,  give up at this point and replace the complete fitting;   it is unlikely to be worth the hassle of opening it up and then re-rivetting,  even if you could source the parts.

    But if the cams will lift off once the securing screws are removed the entire cleat can be dismantled  –  with care.    If your cleats have ball bearings dismantle with particular care,  preferably over a tray or other receptacle,  so that you don’t lose the ball bearings;   and remember that the spring will be under load,   so ease each cam off and allow the spring to release under control.

    Before doing anything else,  check that the teeth of the cams are in good condition;   if they are badly worn the only solution is to replace them.   Some manufacturers will supply replacement cams.

    If they are merely lightly worn and you cannot obtain replacements,  it may be possible to sharpen them up with a three-square (triangular section) file;   your call whether to attempt this,  or instead replace the fitting.     If there is any discernible wear,  even if only slight,  and replacement cams are available it may be worth replacing them anyway.

    Clean everything up,  and reassemble with a little grease.   If you have loose ball bearings,  the grease will also help to retain them in place.

    Expect a full set of ball loose bearings to be one short of completely filling the available space;    if you have physical space for one more it does not mean that you have lost one  –  they do need room to roll.

    Remember that most of the parts are handed,  so ensure that you put each part on the correct side of the fitting;   it may be physically possible to assemble it reversed,  after a fashion,  but don’t expect it to then work properly!

    It can be a little awkward to get the operating spring to seat correctly when you reassemble.    I can sometimes manage it without any tools or other aids,   but where the simple approach won’t work I have found a very useful workaround.    One end of the spring terminates in a right-angle bend,  to provide a vertical spike which engages in a hole in the base plate.    Enter that spike in its hole first,  with the (circular) spring placed around the central pillar.    The other end of the spring is  bent through 180 degrees to terminate in a hook.    Take a length of very thin whipping twine or stout sewing thread,  and loop it around this hook so that both ends protrude well clear of the base plate.

    Then offer up the cam,   and gently lower it on the central pillar as far as it will go;    it won’t quite reach the base plate because it is obstructed by the spring.

    Now use the two parts of the whipping twine or sewing thread to put a little load on the spring,  to pull it into its recess in the cam,   so that the cam will now sit on the base plate,  with only the very thin twine or thread trapped below it.    The thread can now be removed by pulling just one end only.

    Once both cams have been refitted,   with everything cleaned up and greased,  the fitting can now be re-fitted to the boat.

    Hope this helps,

     

    Oliver

  • #20037

    vortexmike
    Participant

    Thanks for the tips. The RWO cleats are rivetted together so imagine it is more work to try and get them apart and then back together than it is worth. I do hate it when items are non-serviceable !!!

    I’m looking on various sites to see if I can find a replacement and will just have to bite the bullet on spending some money I suppose………

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