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  • in reply to: Bent Mast #26614
    Oliver Shaw
    Moderator

    It is also worth mentioning that over the 75-year lifetime of the class there have been numerous different methods of bringing the halliards out of the bottom of the mast,  and cleating them off.

    If it is convenient for you to take your damaged mast to a dealer they should be able to set up and rig a new one so that it is a facsimile of the old one.    Unless you specifically want to update (or otherwise change) the arrangements on your boat,  having the new one set up to the existing pattern could save you a lot of hassle.

     

     

    Oliver

    in reply to: Bent Mast #26611
    Oliver Shaw
    Moderator

    The first question is whether you are insured.    If you are,  this would seem to be a legitimate claim,  for a brand new mast.

    If going for new,  I suggest you get onto the website for either Selden or Super Spars to ascertain who their distributors are in Ireland.     Alternatively it is possible that Alistair Duffin may be able to help you.

    If not covered by insurance,  I suggest eBay,  and also the Classifieds on this site;   and consider posting a classified under the Recycling tab,  and you could also consider posting your requirements on the GP14 Online Community site.    The latter is independent of the Association,  but we have warm reciprocal relations,  and we each support the other.

    Be aware that series 2 masts are shorter than series 1,  and with a different foot.    When I had a new series 2 mast from Speed Sails 15 years ago,  as an insurance claim,  their stock was all made to the series 1 length,  minus the foot;   then when a customer ordered a new mast they shortened a stock one if necessary (i.e. if a series 2 was required),  then rigged it,  and finally fitted the appropriate foot.   It makes sense if manufacturers are producing them all to the longer length,  and then shortening if necessary,  as this probably lowers the production cost.

    If buying secondhand,  it is worth checking that the length is correct.     I have once been caught out,  with what was advertised as a series 1 mast,  and which indeed had a series 1 foot,  but which was actually only the shorter (series 2) length!

    There is currently a “job lot” of dinghy masts on eBay Ireland,  at https://www.ebay.ie/itm/116071327134?itmmeta=01HQJNYQGTBJJNEVBGE4QHJPTE&hash=item1b0663e59e:g:UDEAAOSwDXxlR4o5&itmprp=enc%3AAQAIAAAA4MqEepwDof%2BsToh4ijhpYJ8koUIMg%2BFpjbasUiZYeydDXWmPPRAtWOXdEaE%2FV7v9Ztqpmq4h8AHUu8FROK6kkw7jTuRX2u8gRNHWJ%2B5PI6krjRBJuP6g47XtHzc%2BIXgrYe67DKwJoRKqfkP4dayKiGoWy%2FXEwXLJQxOvnScDRUou4EA5VXltnyKMPfoUvoA0RIndIKwUAm2marPKOufLzVrA4wd7wbHgANL%2FiKrMigAL2mM7UHV0%2FMv%2Fypsr89KJAZ%2FxL9wgnZoqjyWN2NN5%2Fcza1USF0ZtsyPirhGTnCTK%2F%7Ctkp%3ABFBMwPj61bxj.   Make your own enquiries,  of course.

    Hope this helps,

     

     

    Oliver

    Oliver Shaw
    Moderator

    Thanks for that suggestion;    increasing the sizes of the blocks is indeed another sensible way forward.

     

    Oliver

    Oliver Shaw
    Moderator

    I think between us we may have cracked the problem.    Try fitting the spring.

     

    Oliver

    Oliver Shaw
    Moderator

    Thanks for the photos.

    The arrangement seems almost identical to what I have on A Capella (wooden,  by Tim Harper),  where it works well;   I certainly don’t have the severity of a problem that you describe.

    My first reaction to identifying the problem is that in photo gp14-14096-scaled.jpg it appears that the moveable block is failing to “stand up” properly in order to align correctly with the rope.    Next time I go down to the club I can photograph my set-up,  if we think it will help;   although she is a wooden boat the arrangement is almost identical,  and the principles are the same.    However it may be a week or two before it is convenient to do that,  as I am now starting my winter examining season.

    I rather vaguely recollect coming across a system some years ago for putting a stainless steel coil spring around the connecting piece to enable a block to stand up correctly;   indeed it might even have been on A Capella.    That may be a solution for you.

    In your photo gp14-14096-a-scaled.jpg I can’t quite make out where the rope is leading from as it comes into shot,   but it does seem to hint that it may possibly be coming out of the reverse side of a block.

    Hope this helps.

     

    Oliver

    Oliver Shaw
    Moderator

    Fine;   I look forward to seeing your photos when you are able to upload them.    You may possibly need to re-size them first,   there is a limit on file size which you can upload.

     

    Oliver

    Oliver Shaw
    Moderator

    Michael

    You asked a question, and I posted a reply four days ago, but you don’t seem to have seen it!

    I hope the reply was helpful to you.

     

    Oliver

    Oliver Shaw
    Moderator

    Sorry,  but I am not entirely clear what set-up you have,  beyond that you are asking about genoa sheeting and that you have through-deck sheeting.   Through-deck sheeting has benefits in terms of seating comfort,  but in my experience it does tend to suffer more friction than the older on-deck system.

    Photos would be helpful,  please;  and specifically showing all the relevant blocks,  fairleads,  cleat,  etc..

    I have once seen (on Ian Sinclair’s boat) an impressive three-block system beneath the decks,  and that looks to be a good arrangement for minimising friction,  but I have never sailed with that arrangement.   I did at one point buy the fittings to rig that up on A Capella,  but then never got round to fitting it,  because my modified tacking technique (see below) proved to be a satisfactory solution to the friction problem.

    However at a simpler level there are two easy things to try first.   First is to possibly use a thinner rope for the sheet,  and choose the rope for its flexibility and ease of handling rather than for ultimate strength,  as whatever you choose the strength is likely to still be ample.   The thinking here is that thinner and more flexible rope will render through the blocks (etc.) more readily;   but the downside is that thin rope becomes uncomfortable to hold and to pull in when there is any strain on it,  so you are likely to end up choosing a compromise.   I would expect that you are most probably currently using 8 mm diameter;   perhaps try going down to 7mm or even perhaps 6 mm diameter for minimising friction,  although you may prefer significantly larger diameter for comfort in stronger winds;    one compromise may be to switch between light-weather and heavy-weather sheets according to conditions on the day.

    The other thing to try is to adapt your sailing technique slightly to compensate for the friction.  On A Capella I have through-deck sheeting,  and I deliberately chose 10 mm rope for comfort,  which is significantly fatter than most owners choose,  and especially so for use with through-deck sheeting.   This large size is comfortable,  but does result in modest friction,  which is not normally a problem,  except that it becomes acute in the old (lazy) sheet immediately after tacking  –  and I have a solution to that problem.

    The lazy sheet,  i.e. the one on the new windward side,  leaves the fairlead  –  where it experiences slight friction  –  and then has to bend slightly as it goes round the shroud.   Although that bend is very slight it nonetheless exists,  and it causes further friction,  which multiplies the tension in the sheet by a function of the angle through which the sheet turns at that point.   Then the sheet,  now under slightly increased tension,  has to bend around the mast;   which introduces yet more friction,  and especially so as the sheet is already being “tailed” as it rounds the mast by the pull arising from the shroud,  and that in turn is “tailed” by the rope coming from the fairlead.   Then,  when the genoa is moderately hard in (so that its clew is abaft the lee shroud),  the sheet  –  by now under significant tension  –  has to bend around the lee shroud,  multiplying the tension yet further.   Think of how sheet winches on yachts work,  or ships’ mooring bollards on a quayside.    Because the friction is multiplied rather than just added,  it increases exponentially with angle.

    The end result,  in a GP14,  is that this slight friction at the fairlead,  multiplied when the sheet bends round the weather shroud,  and further multiplied when it bends round the mast,  and multiplied yet further when it bends round the lee shroud,  can result in so much tension in the lazy sheet by the time it reaches the clew that it can make it difficult (and sometimes impossible) to pull the genoa fully home.

    My solution to this problem is easy,  once your crew gets used to it,  but it does require a slightly modified tacking technique.    As the boat tacks through the wind the crew physically “overhauls” the old sheet,   i.e. he/she pulls some of the sheet out from the fairlead so as to give plenty of slack,  so that there is no question of the lazy sheet being still under tension.   This is done as a matter of routine,  every time the boat tacks,  and one soon gets into the way of always doing it.    And even when sailing single-handed,  which for myself is probably nowadays the majority of the time,  I still routinely do it on every tack.

    And with that slight modification to tacking technique,  A Capella sails very happily with 10 mm diameter genoa sheets,  sized for comfort.

    Hope this helps.

     

    Oliver

    in reply to: Boat Repairs – MK1 #26383
    Oliver Shaw
    Moderator

    Will try to measure up for the keel sometime;   but it is moderately unlikely to be convenient tomorrow,  and if not done tomorrow I am then away for a week.

    If no-one else comes up with dimensions feel free to remind me in about a week’s time.

     

     

    Oliver

     

    in reply to: Boat Repairs – MK1 #26380
    Oliver Shaw
    Moderator

    That is a good technique that Chris describes,  always provided that you can avoid voids between the two layers of ply,  and I am sure that he paid due attention to that point.

    And staggered butt joints remind me that I have twice in my younger days repaired rot in Firefly dinghies by laminating up thin narrow hardwood strips in crossing diagonal layers,  I think three layers.    If the first layer is thin enough,  and the strips narrow enough,  it is reasonably easy to get them into a fair curve.    Once they are bonded in and the glue cured they provide a reasonably stable surface for laying up the second (diagonally crossing) layer on top of them;   and once that layer is cured you have a good firm surface to lay up the third and final layer.   That method would seem to be adaptable for the forefoot on a GP14,  and it is effectively laminating up plywood in situ.

    I fully concur with reinstating the bulkhead “even for cruising”;   particularly if taken to full height it achieves far more buoyancy than is normally achievable with bags,  and in the event of capsize that additional buoyancy is highly desirable!   The minimum buoyancy required for class rues is just that  –  a bare minimum;   it will enable the boat to be righted,  and bailed out by means of a large bucket,  but it will not make life easy!   Certainly if one wants the transom scuppers to do their job properly it is desirable to maximise the buoyancy in the boat,  and particularly that in the bows.

    Even with a full bulkhead you can still use the enclosed space for stowage;    just fit nice large waterproof access hatches.    Mine on A Capella are nearly a foot in diameter.

    Again I concur with coating everything with epoxy before painting or varnishing.    It might be worth considering Smith’s CPES,  a wood-based epoxy originally designed for treating rotted wood but also increasingly used as a varnish primer.    I have been using it for about the last 12 months,  and am pleased with the results,   although a longer period will be needed to fully evaluate how effective it is in the durability stakes.

    Incidentally if the bow region is to be totally enclosed by a bulkhead it won’t normally be seen,  so you might wish to consider using paint rather than varnish;   it is probably more durable.

    Hope this helps,

     

    Oliver

    in reply to: Boat Repairs – MK1 #26371
    Oliver Shaw
    Moderator

    UPDATE re plywood thicknesses:     you may actually be in luck.

    On checking,  I see that your sail number dates from 1986,  so it seems likely that your boat may be just young enough to have been built with metric plywood.    One website states that plywood has been made in metric sizes since 1978.

    So that may be one problem solved.

    You appear to be on a roll!

     

    Oliver

    in reply to: Boat Repairs – MK1 #26370
    Oliver Shaw
    Moderator

    As a final P.S.;   on a matter of nomenclature,  your boat is a Series 1,  not a Mk 1.     Mark 1 (and II,  III,  IV and IVa) were designators for successive models of early glassfibre boats,  and I am sure you wouldn’t want her to be confused with her GRP sisters  –  especially as you appear to be sufficient of a craftsman and enthusiast to specifically enjoy the wood.

    This is something that many owners are not aware of!

     

    Oliver

    in reply to: Boat Repairs – MK1 #26369
    Oliver Shaw
    Moderator

    It appears from the second set of photos that the damage extends right to the forefoot.

    Although I have never had the misfortune to need to work on this area,  I understand from my reading of the Bell Woodworking book and also seeing Searson Thompson’s film around 15 years ago that this one area is the most difficult part of the entire boat to fit,  because the plywood is forced into a curvature that is just about on the very limit of what it will accept.   According to Bell’s,  their technique was to first secure the ply abaft this region,  and then pour a kettle of boiling water over the ply where it is required to bend so severely,  in order to soften it.

    Link to the copy of the book on this site here,   see page 9.    This page also gives some potentially useful ideas on marking and cutting this area to shape,  and also on the change of bevel at the chine in this area.

    An adaptation of that technique might be a way forward for this apparently very difficult part of the job.

    Hope this helps.

     

    Oliver

    • This reply was modified 1 month, 2 weeks ago by Oliver Shaw. Reason: Inclusion of link to relevant page in the Bell Woodworking book
    in reply to: Boat Repairs – MK1 #26368
    Oliver Shaw
    Moderator

    If you decide on butt joints it is worth considering whether you can use the existing framing to back up at least some of those joints,  at least in part;  and then consider taking the joint a little further outwards from the hole in order to use those structures.    An obvious example is of course the hog,  which is amply wide enough.    At the other extreme,  the (lateral) frames are almost certainly not wide enough,  unless you bond in additional pieces as “sisters” to the faces of the frames in order to provide a greater thickness (fore-and-aft).   Between these two extremes,  the (longitudinal) stringer is narrower than I would wish for use as a backing piece,  but it might make the basis of a backing pad if then further beefed up with judicious use (two or three layers) of woven glass cloth and epoxy over the stringer and extending onto the plywood for at least an inch (and I suggest two inches would be better) either side of the stringer.

    Given the extent of the work involved,  it is worth considering the question whether it might be both easier and more satisfactory to replace the full width of the panel from hog to chine piece,  for the requisite length.    It is difficult to judge from the photos,  but it is worth seriously asking the question.

    One further point to follow.

     

    Oliver

    in reply to: Boat Repairs – MK1 #26367
    Oliver Shaw
    Moderator

    I don’t know whether to be concerned,  or to stand in awe and admiration,  at your intention to use scarf joints.

    A single scarf joint is reasonably easy,   and with reasonable care a good job can be made.   Of course the two gradients need to be a perfect match,  but the precise location of the join is immaterial.

    A pair of matching scarf joints is significantly more difficult,   because (on a typically 12:1 gradient) a slight difference in the amount of wood you shave off the bevel shifts the joint laterally by 12 times that amount;   and if you are trying to slot a graving piece into a gap in such a way that the base of it sits flush and the length is an exact match to the gap this requires some very delicate fitting.     It is easier if both faces are accessible to the plane,  so that you can use slightly thicker wood for the infill,  and then plane both surfaces to get them flush;   but all too often the “inside” surface is inaccessible because part of the structure of the boat is in the way.     I have successfully done a few of these,  on a variety of boats,  when replacing damaged sections of rubbing strake,  and I have been pleased and satisfied with the results;   but I regard them as a demanding test of my skills,  and about the limit of what I can successfully achieve.

    Trying to do four matching scarf joints around the edges of a rectangle is a whole new challenge.   The requirement is,  of course,  to get all four joints neat,  and with the infill piece sitting at exactly the right height,  and with no visible gap around any of the edges;  and moreover to achieve this on a curved surface.    I am sure that the professionals can achieve it,   but when I tried it for two deck infills on my vintage boat I eventually gave up and settled instead for neat butt joints with a backing pad underneath.

    If you are up for the challenge,  and confident that you can make a success of it,  I stand in awe;   but if in doubt you might consider butt joints suitably backed on the inside.

    More to follow.

     

    Oliver

Viewing 15 posts - 1 through 15 (of 677 total)