Forum Replies Created

Viewing 15 posts - 481 through 495 (of 708 total)
  • Author
    Posts
  • in reply to: GP14 with a cuddy #15217
    Oliver Shaw
    Moderator

    You won’t be the first to radically transform an elderly GP14,  or indeed other dinghies.

    There is Philip Hoath’s GP14 Harbour Launch,  there is the Wayfarer complete with (detachable) wheelhouse,  seen at Alnmouth a couple of years ago.

    Not for real,  just playing around with Photoshop,  there is my A Capella sporting the rig of a 40-ft gaff cutter,

    And,  splendidly,  there is the 1/13 scale model of HMS Belleisle,  one of Nelson’s line of battle ships.  http://www.festinalente.org.uk/belleisle/belleindex.html

    Apologies for the duplicated photos;  the site won’t let me delete any once posted.

     

    Oliver

    • This reply was modified 7 years, 5 months ago by Oliver Shaw.
    • This reply was modified 7 years, 5 months ago by Oliver Shaw.
    Attachments:
    You must be logged in to view attached files.
    in reply to: rig tension Bourne Plastics' GP 14 #15212
    Oliver Shaw
    Moderator

    I don’t know the safe limit,  but I would be inclined to play safe,  keeping the tensioning technology in period with the boat.   So any technique up to and including a Highfield lever should be OK,  but a muscle box or a cascade tackle might be risky,  and especially if tailed back to a 2:1 inside the boat.

    In the early days of GRP boats,  which includes at least the earliest Bourne Plastics ones,  there were occasional stories of structural failure,  including chainplates pulling out of the boat.

    Hope this helps,

     

    Oliver

    in reply to: About an old GP14 #15208
    Oliver Shaw
    Moderator

    I have only limited knowledge.

    My primary source is data which was published on a previous Forum run by the Association around a dozen or more years ago;   that data appeared to make sense,  and I accepted it as gospel,  and put it into a spreadsheet.

    I do know that some individual clubs,  and possibly some International Branches,  have issued their own numbers which are distinct from the international numbers issued by the Association.     The best known example of that today is Sri Lanka,  where the Ceylon Motor Yacht Club run their GP14 sailing and have their own set of numbers;   but these are generally single digit or two digit numbers,  so they are easily distinguished from the international numbers,  and particularly so when one finds such a number on an almost brand new boat!

    I would not be surprised if the North America Branch issued their own numbers,  although I don’t know that for fact,  but if so I would expect the numbers to be very much lower.

    For what it is worth,  my spreadsheet shows sail numbers 5001 – 6000 as being issued in 1962-3,  so your supposed date is only about one year different from my records.

    I do have two personal “hooks” which help to validate that spreadsheet.   The first is that I bought no. 4229,  Tantrum,  Sills-built,  second-hand in 1967 at (I believe) about 5 years old.    So she would have been built somewhere around 1962,  which tallies well with the spreadsheet showing that numbers 4001-5000 were issued in 1961-2.

    The second is that a fellow member of my club in the late sixties had a brand new Sills-built GP14 which I much admired,  Eroica,  and if I remember correctly her sail number was 8031.    That tallies well with the spreadsheet showing numbers 8001-9000 being issued in 1968-71.

    However you could ask our Archivist (contact via the Association Office) for a digital copy of whatever records we have of the boat corresponding to your sail number;  then you can see whether those records appear to tally with the boat which you own.

    Sometimes with boats of this age a degree of detective work is the only way to get to the bottom of the mystery;   and it is not always possible to do so.

    And there are very occasional tantalising exceptions to the pattern.   Numbers 11972 to 11992 were used as spare numbers,  and issued out of sequence.

    Occasional owners of new boats were not interested in racing them,  so they did not register them with the Association,  and therefore no number was issued.   Sometimes a later owner then registered the boat,  in which case the date of the hull number (or sail number) could be significantly later than the build date of the boat.    However this is fairly rare.

    Much more tantalising,  in the very early days numbers were issued en bloc to clubs,  and the clubs then issued them to individual owners.   Not all these early numbers were in fact issued to owners,  and I have heard it on good authority that in the seventies one of these unissued numbers was still available from the Royal Northumberland Yacht Club,  at which point it was snapped up by one of the doyens of the class  –  possibly Cubby Ackland,  but I can’t confirm that  –  who then built a “vintage” GP14,  absolutely to the original design and in period with the number,  and registered her under that number.   So somewhere there is a “vintage” 1970s boat with a 1950s sail number,  and built as a 1950s boat.

    And then I understand from Gareth Morris,  who owns no. 7,  that there is a long running dispute as to which of two different boats is entitled to that number.   And we are indeed talking about vintage boats from 1951,  not modern boats from Sri Lanka.

     

    Oliver

    • This reply was modified 7 years, 2 months ago by Oliver Shaw.
    in reply to: About an old GP14 #15206
    Oliver Shaw
    Moderator

    According to my (unofficial) records,  sail numbers 6001 – 7000 were issued in 1963-66;  so the best guess from that data for your boat is late 1963 or early 1964.

    But if you are on this forum you are presumably a member of the Association,  in which case our Archivist can let you have a digital copy of all our records for the boat.   That should include her original measurement form,  assuming that she has been registered  –  and most boats have been,  although there are a few exceptions.   That measurement form should give you her date of build,  and her builder.

    The digital record will also include anything else about the boat which has crossed the Association’s desk during her lifetime.

     

    Oliver

    in reply to: GP centre of gravity #15199
    Oliver Shaw
    Moderator

    Yet another consideration in the context of a combi unit is the stability of the load when the outfit is being towed at speed on the road.    That may well be part of the reason for the nose weight of a combi trolley.

    A possible alternative solution would be to use the original axle position but have an additional removable clock to the bow snubber.  That would enable to boat to be further back when in everyday use at the sailing club,  but pulled forward again for towing.

     

    Oliver

    in reply to: GP centre of gravity #15196
    Oliver Shaw
    Moderator

    I have just measured up,  as best I can (because the boat is currently jacked up at the bows,  and access is obstructed),  one of my vintage GP14s which is sitting on a Chris Brown launching trolley.   That is a clone of the excellent and once near ubiquitous West Mersea combi units,  with the twin cradle design.

    I make it 245 cm from the axle to the bow snubber.     Although that distance may not be exact,  because of the limitations of access,  it will be within a very few cm.

    That is designed to give modest nose weight,  and the trolley can if desired take a jockey wheel.   If the boat is placed on the trolley not fully up to the bow snubber she then can become neutrally balanced.

    There would appear to be some room for experimentation around (and a little below) this 245 cm in order to achieve the desired balance.

    My personal preference on the rare occasions when I need to pull a GP by hand is slight noseweight.    I can manage with the noseweight of one of these trolleys if I must,  but I prefer to use the jockey wheel.   But negative noseweight,  i.e. the boat being stern heavy,  is actually quite awkward for manoeuvring because one has to push down at the same time as pulling;   and zero noseweight (i.e. perfect balance) is almost as bad.  Slight noseweight is ideal,  and precisely how much is optimum is a very personal judgement.

    Another consideration is that the aft support should ideally be some distance abaft the axle,  in order both to ensure that the boat sits securely on the trailer without the bow tending to lift off the bow cradle or chock,  and to at least reduce the long length of unsupported hull abaft the trolley.  The West Mersea design,  now cloned by a number of other builders,  was possibly one of the first designs to offer this feature,  and if you are designing your own trolley it is a feature well worth copying.

    Yet another consideration (for optimum noseweight) is attitude,  and stability,  when parked.   Most of us tie our boats down if using club dinghy parks,  and many insurers require this anyway,  as it is usually best practice.   But even when tied down,  it helps if the boat is inherently stable in her berth,  whether the bow is propped up or not.

    Hope this helps,

     

    Oliver

    • This reply was modified 7 years, 5 months ago by Oliver Shaw.
    in reply to: Spinnaker Pole Length #6436
    Oliver Shaw
    Moderator

    Check the Class Rules (on this site,  Members’ Area)  but from memory all aspects of the design of the pole apart from the length are optional,  and  –  again from memory  –  I am fairly sure that the maximum permitted length is six feet   That length will of course have long since been metricated,  so what appears in the Class Rules will be the metric equivalent,  which is why this dimension (and indeed all the others) are awkward numbers of millimetres.

     

    As to your question “Will it work”,  the crucial considerations are weight and strength,  and if you are cutting down a larger pole it may be unduly heavy.    If too heavy,  it may tend to unduly pull the sail downwards in lighter winds if the uphaul permits it to droop;    using an all-rope uphaul with no elastic in it should help to address this issue.   If not strong enough,  which is less likely to be an issue if you are cutting down a larger pole,  there is a risk of buckling in stronger winds.

     

    In the absence of information I presume that this is aluminium alloy,  and designed as a spinnaker pole,  so both the material and the wall thickness are likely to be suitable.   But early GP14 spinnaker poles were quite commonly made of wood,  and I have also known (older) alloy ones that were too light for the maximum loads they can carry.   The modern GP14 spinnaker p0le is a well engineered tapered alloy pole,  which combines adequate strength with the avoidance of undue weight.

     

    But since you have already picked up this larger one,  the best advice may be to shorten it to the required length and then try it and see.    There is a good likelihood that it will work,  although it may well be heavier than needed.

     

     

    Oliver

    in reply to: GP centre of gravity #15188
    Oliver Shaw
    Moderator

    I can’t be sure about the CoG,  and it would be worth looking up a measurement form to see what (if indeed anything) is measured.   But I think it highly probable that Jack Holt would have originally had at least some idea of the CoG position,  whether or not he fully worked it out.

    What I do know  –  and this provides a minor insight into recent class history  –  is that the principal Moments of Inertia have never been specified,  or definitively measured for the class,  and we have every reason to think it most likely that they vary between different versions of the boat.    This became in issue in 2009/10,  while I was serving on Committee,  when we were alerted that for good reasons modern build was coming out with a weight below our minimum weight specification,  and builders were then having to incorporate additional materials into the construction purely to bring the weight up to specification.

    The light construction arose from two parallel causes.  With the plastic boats it was the move from polyester resins to epoxy resins,  which are very much stronger for a given weight;   so epoxy boats were coming out of the moulds both stronger and lighter than their polyester predecessors.   With the wooden boats,  the cause was the disappearance from the market of traditional boatbuilding hardwoods,  particularly mahogany,  so builders were having to use alternatives which are available nowadays,  and these timbers turn out to have slightly lower density.

    Committee accepted that in order to maintain a level playing field for the racers the weight needed to be made up somehow,  but became concerned that we did not want any particular distribution of this extra weight to give a competitive advantage.   Particular concern focussed on potential changes to the moments of inertia,  and a complicating factor was that these had never been measured,  or specified anywhere in the Class Rules.

    So we decided that we (the Association) would specify what form these additional weights,  to be known as Association Corrector Weights (as distinct from the ones added beneath the thwart to bring the build weight up to the sailing weight),  were to take,  and where they were to be installed.    We wanted to ensure that so far as reasonably possible they would have a neutral effect on the moments of inertia of the boat.

    David Rowlands asked me to do the maths for this,  which I duly did;  we then met to discuss it at the 2010 Dinghy Show,  David then did the design from my maths,  and if I remember correctly it was adopted at the next Committee Meeting.

     

    Oliver

    • This reply was modified 7 years, 5 months ago by Oliver Shaw.
    in reply to: Stepping mast single-handed #15175
    Oliver Shaw
    Moderator

    Sorry;  diagram is still on the “TO DO” list!

    Thanks for the reminder.

     

    Oliver

    in reply to: GP14 Series 1 photos #15174
    Oliver Shaw
    Moderator

    If no-one else comes up with photos of under-deck chainplates I will try to take some;  but it will be some days yet before I can get away from the examining desk and down to the club.

     

    Oliver

     

     

    in reply to: Mast step replacement – MKII GRP advice #15167
    Oliver Shaw
    Moderator

    I might even pay you a visit there sometime;   I am not desperately far away (in South Liverpool).   Perhaps in the autumn,  after I return from my summer cruise.

    A few years ago I was instrumental in rescuing a vintage GP14,  no. 47,  Caltha,  for restoration,  from a youth organisation who kept her at Budworth SC.    Understandably,  they could not really maintain her or restore her,  and they had different priorities,  so they were keen to find a good home for her.

    She is now in very good hands,  owned by a friend of mine and a fellow member of Liverpool SC.    After a fairly major restoration she occasionally gets her bottom wet for special occasions,  and two or three years ago the two of us celebrated her restoration by racing her in a vintage event on Bassenthwaite,  her first time out since the restoration.

     

    Oliver

    in reply to: Mast step replacement – MKII GRP advice #15142
    Oliver Shaw
    Moderator

    Dave,

    I am up to the eyes with exam marking at the moment,  but I have just emailed Steve,  and I would hope that he may be able to assist you.

     

    Oliver

    in reply to: GP14 Series 1 photos #15133
    Oliver Shaw
    Moderator

    Final two photos attached.

     

    Oliver

    Attachments:
    You must be logged in to view attached files.
    in reply to: GP14 Series 1 photos #15128
    Oliver Shaw
    Moderator

    Ah!  Found six photos of the genoa tracks on Strait Laced,  dating from a little over ten years ago.   The system will allow me to post only four at a time,  so I will post the first four here and the last two in a subsequent post.

    These were taken while the boat was under repair,  and some (mainly the two which are to follow this post) show the tracks in place while others show the tracks removed  –  but the change in colour of the wood clearly shows where they were placed.

    On this boat the tracks were mounted some way inboard,  but it is also clear from the photos that at some time previously (prior to my ownership) they had been much further outboard.   Best advice there is to experiment with the set of your sails ashore,  on a fairly average day  –  say around force 3  –  with a steady wind,  with the boat on her launching trolley or road trailer.    Point the boat at around 45 degrees to the wind,  as though for beating to windward,  and hoist both sails,  and just holding the sheet by hand experiment to see where you are going to want to lead it to on the deck in order to achieve a good shape,  with the sheet roughly in line with the diagonal seam in the sail (if there is one),  with a good slot between the two sails,  and with the sails setting nicely and not fluttering.    That will be a pretty good way of determining where on the deck the tracks are best placed for your particular sails.

    If there is no diagonal seam in the sail three fairly standard dictums are (1) bisect the angle at the clew,  or (2) the line of the sheet (extended) should intersect the luff at right-angles,  or (3) the line of the sheet (extended) should intersect the luff at about its mid-point.    Note that these three are only starting guidelines,  and they may give slightly different results,   but any guide is no more that a point to start from;   then you need to experiment to see what gives the best looking set overall,  with a good aerofoil shape,  a good slot (narrow enough to accelerate the wind flow,  but not so narrow that it backwinds the main),   and both sails setting without fluttering.

     

    Oliver

    Attachments:
    You must be logged in to view attached files.
    in reply to: GP14 Series 1 photos #15127
    Oliver Shaw
    Moderator

    Although I won’t be sailing this weekend it is possible that I may be able to get some photos for you.    I will try,  but can’t promise;   so if anyone else can help,  please do so.

    However I can answer a couple of your questions.   Adjustment of standing rigging;   your choice!   The original boats almost universally used rigging screws (aka bottle screws),  which may perhaps be what our American friends call turnbuckles  –  but here in the UK that term means something different.   http://juststainless.co.uk/wire_parts.asp?cat=JSWS

    However the more modern approach is to use rack type shroud adjusters,  vernier or otherwise,  with just a lanyard for the forestay.  https://www.sailboats.co.uk/selden-dinghy-shroud-adjuster

    The links are not necessarily intended as recommendations,  merely to illustrate general types.

    “Yer pays yer money an’ yer takes yer choice!”

    Self-bailers:  ideally two,  as near the centreline as is reasonably possible,  at the lowest point in the bottom of the boat;   this will be either side of the centreboard case,  just a little forward of the aft end of the case.   By far the most effective design of self-bailer is what used to be called the Elvstrom and is now called the Andersen bailer.   They are available in a range of sizes,  and I would recommend a pair of either the largest or the next size down.   They are available in versions for mounting either externally (in which case you will need to recess the plywood) or internally (in which case you may need to use shims to achieve a flush external profile.   https://www.sailboats.co.uk/elvstrom-andersen-super-max-self-bailer  This link is to just one bailer from the range.

    Hope this is helpful to you.

     

    Oliver

     

Viewing 15 posts - 481 through 495 (of 708 total)