GP14 restoration. Internal compartments

GP14 Sailing Forums Forum GP14 restoration. Internal compartments

This topic contains 6 replies, has 3 voices, and was last updated by  Chris Hearn 1 week ago.

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  • #13443

    DHUGHES
    Participant

    Hi All.  I am restoring a fairly new GP14 that looks to have lived outside for a couple of winters and is now in a sorry state for a 5 year old boat.  I’m not new to working on wood end boats, but am mostly familiar with Mirrors.

    All the deck varnish now needs to come off as there is lots of frost damage from the wood getting damp then freezing.  My question is, is it a good idea to use bilge paint in the forward compartment and possibly under the side and rear decks to help seal the wood from the inside and back?

    it seems strange that all Mirrors are totally coated on the inside, (and probably why they last so long), but my GP looks to have VERY minimal coating on all of the “out of sight” areas.  It seems odd to have a lack lack of finishing, to then have to fit a load of lead weights to bring it into class?  Is this common practice on new GP14’s.

    It will take a lot of work as most of the exposed woodwork has been frost / moisture effected, but it is my intention to strip and re epoxy cost, then 3 or 4 coats of 2 pack for a longer lasting Finish as the wood is still very sound with no sign of rot. A bit more varnish and coating when built, would have saved a lot of hassle down the line.

    #13444

    Oliver Shaw
    Moderator

    Oh dear!

    My impression is that all professionally built GP14s built in recent years are fully coated in epoxy inside and out during the build process,  and most certainly that was my clear understanding from my builder (Tim Harper) when he built A Capella for me in 2005/6.

    Of course amateur built boats may not necessarily be to the same standard;   that all depends on the individual builder,  but I also have the impression that amateur built boats form only a tiny minority of the modern ones,  and especially so since Fyne Boats dropped the GP14 kits from their range some years ago.

    This suggests that perhaps your boat may be significantly older than you had thought,  or alternatively that she is one of the comparatively few amateur built ones.   Do you have her registered hull number?   (On a Series 2 boat look on the aft face of the centreboard case,  just above the cockpit sole.)   Do you know who the builder was?   (Assuming she is registered with the Class Association,  her original measurement form should be on file,  and it should show the name of the builder.)

    Either way,  the problem is what to do now.     Most certainly I would recommend sealing all the hidden surfaces of the wood.   If you can get the wood properly dry and clean,  consider using epoxy as a sealant;   the headline product is WEST epoxy (or similar),  but that may be difficult to apply retrospectively inside the buoyancy tank,  not least because of limited access   –  that may make it extremely difficult to get back to clean wood,  and may also make it difficult to apply the epoxy right into the corners and crevices.   If you do go with WEST (or similar) epoxy despite the difficulty of access,  consider warming both the wood and the epoxy to achieve easy flow,  but use the slow hardener to still allow you reasonable working time at the warmer temperature.

    It is possible that Interprotect (an epoxy polyamide primer by International Paints) may be easier;   that is not a product that I myself have ever used,  but I have considered it from time to time,  and certainly it is worth a call to their Technical Helpline to discuss it with them.

    If you feel that the restricted access makes it difficult to do the job adequately with epoxy,  than a good quality bilge paint (e.g. Danboline) would seem to be a good fall-back option.

    Finally,  when you are ready to revarnish,  I would recommend using a minimum of 6 coats on top of your epoxy.   No point in spoiling the ship for a ha’p’worth of tar.

    Hope this helps,

     

    Oliver

    • This reply was modified 1 week, 3 days ago by  Oliver Shaw.
    • This reply was modified 1 week, 3 days ago by  Oliver Shaw.
    • This reply was modified 1 week, 3 days ago by  Oliver Shaw.
    #13457

    DHUGHES
    Participant

    Hi Oliver.  Thanks for the reply.  I’m going to fit another inspection hatch into the front tank, so I can perform a bit of keyhole surgery – look through one and paint through the other (brush taped on a stick)  It not my intention to embarrass the builder as a lot of the problem has been caused by neglect, so I would rather not list the number (it’s well over 14000)  I just want to get the boat right for the next 10 years.   I still own a 10 year old professionally built Mirror, and the difference in build quality is chalk and cheese.   I will take your advice on the number of coats to put on as I feel that is the root of the original problem.  There are also a couple of areas of wear on the centreboard case, so I have bought some Tufnell to inlay to prevent it happening again.

    Many thanks and any advice is greatly received.

     

    #13458

    Oliver Shaw
    Moderator

    If you are intending to fit an additional access hatch you may wish to consider fitting a seriously large one,  ideally one each side.

    The ones I had fitted to A Capella,  as per the attached photo,  were almost 1 foot in diameter.     That gives vastly better access,  and better ventilation,  and additionally (for cruising) it enables you to use the tank for stowage of light but bulky items which would otherwise be aboard the boat anyway;   probably not an issue for racing,  but I stowed my inflatable fenders in there.

    Expensive,  but perhaps worth considering.    I see that Force 4 are currently listing some very similar non-lockable ones by Bomar.

     

    Oliver

    • This reply was modified 1 week, 3 days ago by  Oliver Shaw.
    • This reply was modified 1 week, 3 days ago by  Oliver Shaw.
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    #13469

    Chris Hearn
    Keymaster

    Hi David,

    Oliver has covered the restoration very comprehensively. I have an older GP14, sail number 13509, and it has varnish on the inside of the cockpit but minimal in the forward compartment – I was told this is to allow the wood to breathe and moisture somewhere to escape. Whatever the merits or otherwise, I have never had any problem on my boat, which is considerably older than yours. However I do leave the hatch cover off when not on the water – which is good practice especially in summer when expanding air on hot days can create a lot of pressure inside the bow compartment.

    It seems odd to have a lack lack of finishing, to then have to fit a load of lead weights to bring it into class?  Is this common practice on new GP14’s” .

    Lack of finishing is a separate thing. It is common practice to add lead weights. All boats want to be a minimum weight for racing, so the builder makes them a little underweight and adds lead to bring them up to the legal minimum.
    An advantage for wooden boats is that they do tend to increase in weight with age, so the lead can then be adjusted.
    Having said that, I found it impossible to remove the weight on my boat as it was very well fixed under the thwart and the screw head slots were poor. I didn’t pursue it because I reckon at my level of skill the “guy in the back” is making much more difference than a few kilos of lead, so the focus should be on getting my skill level up 🙂
    I do look at my rig setup though, as again I reckon that’s a bigger impact for racing if it is set up poorly. If I was competing at a higher level that would be different!

    Chris

    • This reply was modified 1 week, 1 day ago by  Chris Hearn.
    #13473

    Oliver Shaw
    Moderator

    A little bit of history,  and further explanation,  for you.

    Chris notes that builders (choose to) make boats slightly underweight in order to obtain the best racing performance,  and then add corrector weights to bring them into class.   Historically that has long been the case,  but in recent years an additional and larger factor has come into play.

    The origin of the particular figure for the minimum weight is that this was a (standardised) weight,  close to that at which a newly built wooden GP14 would naturally come out if well built,  using top quality materials.

    By 2009/10,  at which time I was serving on committee,  David Rowlands made us aware that the natural build weight for new boats,  both wooden and plastic,  had reduced as a result of changes in materials used.    In the case of plastic boats it was due to the switch from polyester to epoxy resin,  which naturally produced a lighter boat even though at the same time it was also stronger than its polyester predecessor.   In the case of wooden boats it was because of the near total disappearance from the market of the older traditional boatbuilding woods,  resulting in builders having to switch to alternative woods,  which happened to be less dense.

    David advised us that in both types of construction,  builders were then adding additional material,  structurally unnecessary,  for the sole purpose of bringing the finished build weight up to specification.   Depending on precisely where this material was added it could affect one or more of the boat’s principal moments of inertia,  three physical properties which control how rapidly the boat will turn and pitch and roll,  and he advised that this could conceivably give a competitive advantage to particular solutions to this problem.    On David’s advice,  committee therefore wished to control where and how this additional weight was to be added,  and in particular we wanted to achieve this in such a way as to have a neutral effect (so far as reasonably possible) on the moments of inertia.    The result was the introduction of “Association Corrector Weights”,  additional to the weights secured to the underside of the thwart,  to bring the build weight (as distinct from the sailing weight) up to specification.

    David did the overall design for this project,  and I did the underlying maths for it.

    I can date the conclusion of this project to the precise year,  2010,  because that was the 60th anniversary year of the class,  and as part of those celebrations the Association were exhibiting two of my boats (A Capella,  a then fairly new and well equipped dedicated cruising boat,  and Snowgoose,  a vintage boat from 1951,  the first year of the Class) at the RYA Dinghy Show.  And it was while we were both on the stand at that show that David and I went through my mathematical analysis,  which he then used in finalising his design.

     

    Oliver

    #13476

    Chris Hearn
    Keymaster

    Ooh yes, that’s quite right Oliver! As my GP14 was built in 1997, so is now 20 years old, it only has the single corrector and I had forgotten about more “recent” changes!

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