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  • in reply to: Mast Step Conversion #10520
    Oliver Shaw
    Moderator

    I hope someone who knows this conversion intimately will pick this up;   I know it only from a theoretical viewpoint,  and I don’t have the plans available.   However a few overriding principles may be helpful.

    1.  Preserve the overall height of the plinth which you are building,  on which the mast track rests;  and of course preserve the horizontal location of the mast track,  and shorten the mast by exactly the specified amount.

    2.  I would build up the frame to the required height,  but I would also take steps to ensure that your additional filler piece is strongly bonded to either the frame below or to the plinth above (but not to both,  for the reason in point 4) and is also supported against “capsizing” in the fore and aft plane.   Two alternative ways to achieve the latter support are (a) fit a backing piece to the frame and filler piece,  on their forward faces,  bridging the joint,  or alternatively (b) use a filler piece at least twice the thickness of the frame (in the fore and aft direction),  bond this to the plinth above,  and cut a recess out of the spline below to accommodate the (wide) filler.

    3.  The conversion is designed to spread the load so far as possible,  so preserve this.   Ensure that the plinth (the top part of the job) <span style=”text-decoration: underline;”>bears throughout its length</span> onto the parts beneath;   in order,  from forwards,  frame 1 (if it goes that far  –  I am not sure on this detail),  the spline,  frame 2 (via the filler piece),  and the recess in the centreboard case.    No horizontal gaps left anywhere.

    4.  For an older boat which is known to have some problems,  allow for the possibility that at some future date the centreboard case may have to come out for repair or re-seating.   With that in mind,  unless you know beyond doubt that the case is properly bonded to the hog with epoxy (i.e. modern practice,  as opposed to the earlier practice of bedding it onto mastic),   I would build up (and bond) <span style=”text-decoration: underline;”>everything except</span> the plinth,  ensuring that you create a smooth level surface,  and keep the plinth entirely separate at this stage.     Apply your chosen finish,  varnish or whatever,  to <span style=”text-decoration: underline;”>all</span> surfaces of both parts,  including what are going to become the mating surfaces.   Then <span style=”text-decoration: underline;”>screw</span> the plinth into place,  bedding it down onto a very thin film of sealant,  but do not bond it in place.    Doing it this way,  if you later need to remove the centreboard case the plinth can easily be removed first,  without damaging it,  and it will not make it more difficult to take out the centreboard case.

     

    Oliver

    in reply to: Composite Mast … … #9976
    Oliver Shaw
    Moderator

    Ugh!!

     

    Sorry about that formatting glitch.    What I intended to write was this:

     

    We have a moderately new member in my sailing club,  with a Mk 2 composite boat.

     

    Having looked a couple of weeks ago,  with come concern,  at his mast while it was down for road towing,  when I happened to bump into him today as he was about to launch we got into conversation,  and I raised my concerns about the mast.

     

    The problem is that it appeared to be a badly repaired wooden mast,  complete with a number of butt joints,  albeit staggered,  which appeared to give the spar the bending strength of a spar of only about half its width.

     

    However it transpires that those joints are not structural;  what provides the strength is the aluminium pole up the inside …   …

     

    The story is that he particularly wanted a wooden mast,  in keeping with the age of the boat,  but they are almost impossible to obtain secondhand,  and he tells me that a new one will cost about £1,000.    That is about £300 more than the last price that I saw,  but in fairness I think it may have been back in about 2008/9 that I priced them;   at any rate it was several years ago,  so the increase over those years is not unreasonable.

     

    So he made his own mast,  starting with that aluminium pole,  and he then clad it in timber.

     

    An interesting approach,  although I am sure it is not in class.    But for non-racing that doesn’t actually matter.

     

     

     

    Oliver

     

    in reply to: Late Series 1 wood spinnaker bags/ halyard bags. #9836
    Oliver Shaw
    Moderator

    You mean the bucket?

     

    There are also four fenders visible.

     

     

    Oliver

    in reply to: Late Series 1 wood spinnaker bags/ halyard bags. #9798
    Oliver Shaw
    Moderator

    Sorry,  attachment was too large.

     

    Trying again,  with reduced file size.

     

     

     

    Oliver

     

    in reply to: Late Series 1 wood spinnaker bags/ halyard bags. #9797
    Oliver Shaw
    Moderator

    You may well find that a series 2 spinnaker “bag” will fit,  or alternatively you could have a bag or net made to measure.    There are plenty of firms who will make canvaswork to order,  and the attached photo shows a pair of spinnaker nets on a series 1 that I owned a dozen years ago  –  albeit that I used them for stowing a limited amount of cruising kit rather than the spinnaker.

     

    Alternatively you could stow the spinnaker in a bucket.   That works well,  and the bucket will double as your emergency large capacity bailer,  which (in a series 1) you are very likely to need in the event of capsize.

     

     

    Oliver

    in reply to: Wooden boat care #9767
    Oliver Shaw
    Moderator

    Norman beat me to it,  but I concur.    And certainly I would use the waterproof tape if you intend sailing much more than just this first weekend before you start repairs.

     

    Then you can do a proper job over the winter.

     

     

    Oliver

    in reply to: Sail Dimensions #9640
    Oliver Shaw
    Moderator

    Try the Class Rules;   on this site in the Members’ Library

    in reply to: sail number boat age etc #9626
    Oliver Shaw
    Moderator

    I am not aware of anything covering the more recent boats,  but the data on the older boats is available.

     

    Around ten years ago the data was on the then forum,  and I copied that into a spreadsheet,  and during my days on Committee I periodically updated it from the regular statistics of new registrations,  but that as some time ago so it is now no longer up to date.    This can be found on the GP14 Owners Online Community site.

     

    It would be well worth updating it to the latest boats,  and then keeping it up to date,  and publishing it on the main Association website.

     

     

    Oliver

    in reply to: Whisker Pole #9625
    Oliver Shaw
    Moderator

    If you already have a spinnaker pole you could use that;   the lengths are the same,  and a small loop of line (about 4 mm) permanently attached to the clew of the sail will enable the end fitting to attach to the sail.

     

    If you don’t have a spinnaker pole,  the stresses on a jibstick are pobably somewhat lighter,  so you could make one out of wood.

     

    I imagine that you don’t intend to use it in competitive racing,  so although Class Rules are a useful guide you need not be a slave to them.    Your choice of design;  length 6 feet.

     

     

    Oliver

    in reply to: Wire rope halyard. Rope replacement? #9596
    Oliver Shaw
    Moderator

    I concur with all the Norman has said.

     

    Just one addition:   the ability to splice three-strand rope is a skill which is well worth learning,  and there are guides to the method available on the internet or elsewhere.<b></b><i></i><u></u>

     

    I am told,  but have no first-hand experience,  that splicing braided rope can also be very easy;   but the rub there is that you need a special splicing needle,  and the size of needle has to be correct for the particular rope  –  so you end up needing a supply of needles of all different sizes.

     

     

    Oliver

    Oliver Shaw
    Moderator

    I should have said that if you intend to sail one the sea or in estuaries you need an anchor;   it is at least as important in estuaries.    There may even be a case for carrying one when sailing on lakes,  for any sailing other than racing.

     

    But if you intend sailing on inland waters only,  and if you intend that inland sailing to be only racing,  then an anchor is probably not needed and you won’t want to carry any excess weight while racing.

     

     

    Oliver

    Oliver Shaw
    Moderator

    It where the split might be sensible when you do the full job to put backing pieces underneath the deck where the split tails go though.

     

    Painter:  I would recommend around 10 to 15 feet “working length”,  i.e. measured beyond the stem,  but be guided by the local conditions at your normal club or sailing base;  see what length other owners use.    Add to that the distance from the stem of the boat to wherever you intend to secure the painter.    With modern ropes the diameter is determined by comfort in handling;  even if it is far too thin for comfort it will often have enough actual strength.    I would recommend 6 to 8 mm rope,  fairly soft and supple,  and my personal choice of construction for this is 3-strand because it is easy to splice;   as regards material,  polyester is perfectly adequate for a painter.

     

    I see no need for the painter to have any stretch,  but it is very advantageous for an anchor warp to have stretch,  and the recommendation for the latter is nylon,  for that reason.   However polyester,  provided it is not pre-stretched,  is almost as stretchy as nylon and is an adequate substitute.   And indeed back in the sixties,  when we knew no better,  many of us used 3/4-inch prestretched terylene,  the least stretchy material of the day,  and in that respect the worst possible choice,  as standard for our anchor warps,  and never had a problem with that choice.   But stretchy nylon is better.

     

    If you intend sailing on the sea you do need an anchor,  and I would recommend either a good Danforth-type or a good Bruce-type,  at around 2 kg,  with a couple of metres of 6 mm chain and 30 m of 6 mm warp.   Avoid folding grapnel anchors,  which are utterly notorious for not holding;   a leading candidate for the nautical equivalent of the square wheel award.    In dinghy sizes plough types (e.g. the famous CQR) are also best avoided,  as they tend to be unreliable,  although the larger ones work well for yachts.    One of the best of all anchors is the Rocna,   but they are designed for yachts rather than dinghies,  and the minimum size which they make is 4 kg,  which is heavier than you are likely to need.

     

    If intending to anchor you do also need an anchor fairlead,  as close to the stem as possible,  so that the anchor warp is constrained to pull at the stem of the boat and not over the side;   in extremis the latter is a good recipe for a capsize while anchored.   It is also a good idea to use it when temporarily mooring your boat by her painter,  and also when being towed.

     

     

    Oliver

    Oliver Shaw
    Moderator

    I am struggling with a difficult mobile connection,  and viewing your photos in sunlight,  so I am having some difficulty with them.

    Very clearly the varnish is discoloured and is lifting in the affected areas;    I take your word about the actual wood lifting as this is not clear in the photos,  but so far as I can judge any gap between parts of the wood is still small.

    I suggest that you remove the damaged varnish;  your choice whether to use a chemical stripper (and I find the Originl Nitromors,  in the yellow can,  by far the best on the market) or a hot air gun;   but do use a seriously sharp scraper,  and keep it sharp.    My choice nowadays for scrapers is one of the (limited number of models) with a silicon carbide blade;   they come ready sharpened,  they keep their edge vastly longer than ordinary tool steel,  and when the edge does go you simply replace the blade.

    Having removed the varnish (from the damaged area only) you can then better assess the wood.    Use a thin blade to clean out any gaps so far as possible.   You then need to endeavour to insert fresh adhesive,  preferably without taking the joint apart,  and that is difficult.   Two good options to consider:

    (1)  neat epoxy run into the joint,  perhaps injected with a large hypodermic syringe (you may well be able to buy this from the same chandler as you buy the epoxy,  and you want a cheap plastic hypodemic because you will use it only once and then throw it away).  WEST recommend that you do not thin the epoxy to help it to penetrate,  because this degrades its strength;   instead they recommend that you warm both the work and the mixed epoxy in order to reduce its viscosity,  but if you intend doing this you should then use the slow hardener in order to still allow a reasonable working time before it goes off.

    (2)  WEST now have a new product available,  called something like SIX-10 or perhaps SIX-50,   which may be helpful.   This is a two-part thickened epoxy which comes in a cartridge which contains the two separate parts and which fits a standard cartridge gun,  and the nozzle is a specially designed mixing tube,  so what emerges from the end is ready-mixed.    The benefit of this product for your particular job is that by placing the nozzle hard against the gap you may be able to force the thickened mixed epoxy into the gap.

    That deals with the structure.    will respond later regarding the varnish.

    Hope this helps,

     

     

     

    Oliver

    in reply to: Foot-straps – Securing to Hull #9426
    Oliver Shaw
    Moderator

    I suspect that Steve White will be the best expert for the detail on this,  but I am not sure whether he uses this Forum.   If he doesn’t come in on this,  try the GP14 Owners Online Community.

     

    However building up a mount direct to the hull should be viable,  and with a sufficient number of layers of GRP and spread over a reasonable area it should be massively strong.   My own preference is for woven glass mat or rovings,  or woven glass tape rather than chopped strand mat,  because I understand it is stronger.

     

    A few other points:

     

    1. Use epoxy,  absolutely not polyester.    Polyester (which is what was used in the original build of your boat) is fine for original construction,  laminating up wet on wet,  but it does not have good adhesion to existing solid substrates,  not even to cured polyester.   Epoxy,  by contrast,   offers possibly the best adhesion you can obtain;   and as a bonus it is stronger than polyester.   Unfortunately it is also more expensive,  but a standard 1kg pack will probably not break the bank,  and is probably more than sufficient for the job.

     

    2.  Clean up the substrate first,  fairly brutally if necessary;   an angle grinder works fine for this.   Then remove all dust,  and clean off any remaining dust and other residue with acetone.

     

    3.  Be very strict about measuring out the correct ratio of quantities,  and insist on dry and warm conditions for doing the job.   Personally I measure by weight,  and some years ago I bought myself a cheap electronic  kitchen balance for this specific purpose.    But don’t make the mistake which I originally made,  of putting your mixing tin direct onto the balance,  and then afterwards cleaning off any splashes on the display window with solvent;  it will just craze the window,  and write off the balance.    Now,  on my second cheap electronic kitchen balance(!),  I first put the balance inside a transparent polythene bag;   then any splashes remain on the outside of the bag.

     

    4.   Most important;  wear eye protection when handling the hardener.   Eye injuries due to splashes of hardener into the eye are very rare,  but at least in the case of polyester hardener it was reported in the seventies that they can be progressive and irreversible,  potentially leading to blindness.   It is not worth the risk.   I don’t know whether this also applies to epoxy,  but I choose to play safe just in case.

     

    The rest is just basic fibreglassing techniques.

     

    Hope this helps,

     

     

    Oliver

    in reply to: The Re-hull project #9402
    Oliver Shaw
    Moderator

    I commiserate with you on the demise of your Sills boat;   they were regarded at the time as the then Rolls Royce of GP14 builders,  and even only a very few years ago there was a comment on the website of West Kirby SC,  a top racing club, n that “Those old Sills boats were good.”   Incidentally they also built Herons,  and we have one in my club.

     

    My second GP14 was a Sills one,  much loved,  which I had from either 1967 or ’68 until the mid-seventies.

     

    I had a tour of their works in the late sixties.    They told me that they were not primarily boatbuilders;   that was just a sideline.   Their primary work was industrial patternmaking,  making hardwood precision patterns for forming male moulds for industrial precision casting;   they would be used to form “sand” female moulds,  then the hardwood pattern removed,  and finally the molten metal poured in.   The particular area they were working in required the finished casting to be as accurate as possible prior to machining.   No wonder they were very firmly into precision woodwork.

     

    They told me the delightful story of an order which they had just completed for the Army,  who wanted a fleet of six GP14s for recreation and training;    but they would never be raced in civilian competition,  and there was no need for them to measure to Class Rules,  so perhaps some short cuts could be taken in the build,  and the Army wanted a competitive price.

     

    The contract was agreed,  and Sills built the boats.  And they did indeed take some short cuts;  instead of measuring and checking everything,  they simply built them to their existing jigs without any other measurements.

     

    Then,  for their own satisfaction,  when they had finished they took one at random and put it through a full measurement check.    The biggest discrepancy that they found was 1/16 inch!

     

     

    Oliver

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