Mast tension MKII GRP and Rodents

GP14 Sailing Forums Forum Mast tension MKII GRP and Rodents

This topic contains 19 replies, has 5 voices, and was last updated by  cookie 2 weeks, 1 day ago.

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  • #17513

    cookie
    Participant

    Hi Guys,

    Tails from the boat yard, a lesson well learnt … Now it’s that time of year when my mind turns to getting back on the water, so in preparation for the forthcoming event I popped over to the club on Sunday to inspect the boat and what did I find…

    …To my surprise I found that something had gotten under the cover and gnawed its way through by sail bag (that will teach me!) and chomped a nice big hole in may mainsail! about 20mm x 40mm and about 300mm up from the foot.  Never leave your sails in the boat!

    The boat being quit old, but cherished, didn’t set me back much so I can’t justify paying for a new cruising main. Does anyone know where I might pick up a reasonable priced used mainsail from? I could always tape it ;0)

    On to the main topic of this post,  My GP14 is a MKII 1972 sail number 10164. She has rope halyards for Main and Genoa and I find it almost impossible to get enough tension on the genoa halyard. The halyard is pulled from the base of the mast and secured on a cleat that’s fastened to the centre board casing. The halyard can then have more tension applied to it by means of a tooth arrangement that is fixed to the centre board casing vertically.

    Is there a better way I can tension the rig? I was thinking of fitting a Highfield lever but not sure if the mast will take the extra tension?

    Can anyone advise.

    Thanks

    Dave

    • This topic was modified 3 weeks, 5 days ago by  cookie.
  • #17515

    Oliver Shaw
    Moderator

    Just a check first to ensure that we are talking about the same animal;   sail number 10164 does indeed date from 1972,  and since you say Mk II I read that as the second model of the GRP boat,  which is consistent with that date;   not the Series 2 wooden boat (which is not consistent with either that sail number or that date).     Many owners get Mk 2 (or Mk II) and Series 2 mixed up,  but you seem to have got it right!

    Pity about the rodent damage …

    I am sure that your mast and your boat will safely take a Highfield lever,  but probably not a cascade tackle or muscle box.    That may give you a little more rig tension than your present system,  although if your cleat is at the aft end of the case and you get the halliard as tight as possible before you cleat it off and then tighten it further by the toothed rack there is probably very little in it.    The big difference may be in convenience;    with your present arrangement it is probably quite difficult to actually get enough tension on the halliard before you cleat it off,  because the geometry doesn’t really lend itself to your “sweating the halliard up” on the cleat before making it fast,   and getting that initial tension is absolutely crucial.

     

    Oliver

  • #17516

    norman
    Participant

    Hi Cookie,

    It may be too simple a question, but do you have someone pulling hard outward on the forestay when you are initially tensioning the genoa halyard?  It does enable you to get a bit more tension than a simple pull on the halyard.

    Norman

  • #17517

    cookie
    Participant

    Thanks again Oliver, You know I’m not very strong and have arthritic shoulders and wrists so I’ll go with the Highfield. The T section that slots into the mast comes in two sizes. Either 6mm or 12mm any idea which one I should get?

    Also, my accuracy regarding my boat detail is down to the information you kindly provided last year which from your description of the desdingushing features matches perfectly. So thanks again.

    Dave

    • #17520

      cookie
      Participant

      Hi Norman, When I have crew yes, but mainly take it out on my own. Also want the ability to rig/derig on the water. Thank for advice though.

  • #17521

    Oliver Shaw
    Moderator

    Dave,

    I am not entirely clear what you are referring to when you you say “the T section that slots into the mast”.

    I have a dinghy-size Highfield in front of me as I write,  and although I don’t use it on my vintage GP14 (but only for reasons of historical authenticity) I have just checked that it fits my IYE mast.    Without getting out callipers to check,  I make the securing screws to be 4 mm diameter,  and the backing plate is 15 mm wide.    There is no T-section on this one,  although that does not rule out there having been changes in design more recently..

    Hope this helps,

     

    Oliver

     

  • #17522

    cookie
    Participant

    Sorry for my ham-fisted explanation Oliver, I was trying to explain the dimension of the bit that slots into the mast in the same way the goosneck does.

    Not being near my boat I cant measure it and I thought you might know before I placed my order online. They come in a variety of sizes and I’m not sure which I should get. They come in the following sizes as advertised:

    Allen Ratchet Highfield Lever 16×2

    Allen Ratchet Highfield Lever 13×5

    Allen Ratchet Highfield Lever 12×2

    I would guess from you description it would be the 16×2

    Dimensions:
    Ratchet Highfield Lever – 16 x 2mm
    Ratchet 3 fixings, flat backing plate.
    Throw: 75mm
    Adjustment: 63mm
    Backing plate size: 16 x 2mm
    No. of adjustments: 6
    Weight: 193g

    Thanks

    Dave

  • #17523

    Oliver Shaw
    Moderator

    Yes,  that seems to be the same as the one I have in front of me.

     

    Oliver

  • #17524

    Oliver Shaw
    Moderator

    Do be aware that Highfield levers are a bit notorious for finger injury.  …

    The danger arises because the lever goes “over-centre” while under heavy load,  and if you are unprepared it can then take charge,  trapping your fingers between lever and mast.    However there is a safe technique.

    When tensioning the halliard,  once load starts to come onto the lever use the heel of the hand to push the lever fully closed,  keeping fingers well out of the way.   It may help to make a point of keeping the fingers straight,  and then you won’t even be tempted to wrap them around the lever.

    When releasing the halliard the danger is that once the lever goes past “over-centre” it may then fly open with considerable force.    A safe technique here is to use two hands;   one hand (and you will need briefly to use the fingers for this) to initially pull the lever backwards,  away from the mast.   This phase of the operation is accomplished within about the first inch of movement (as at the end of the lever).     While doing that,  use the heel of the other hand on the outward side of the lever to check its movement,  again keeping the fingers of that hand straight,  and very definitely not wrapped around the lever;    once the lever starts to open further of its own accord (after the end of the handle has moved perhaps an inch and a half) release the first hand and use the heel of the second hand to control its motion,  so that you allow it to open smoothly and under control rather than violently.   And in the last resort,  if you do not manage to keep it under control,  at least the fingers (of both hands) will be well out of the way.

     

    Oliver

  • #17530

    steve13003
    Participant

    Hi,

    When changing to a new tensioning system you will also need to change to a wire halyard for the genoa.

    Although Oliver expressed concerns about the use of a cascade system or a muscle box for tensioning the genoa they do avoid the risks of serious damage to fingers and are easier to use than a hifield lever especially when single handed.  To avoid overloading the rig just don’t pull on to the maximum.  Borrow a rig tension gauge and apply a load of about 250lbs rather than the 400lbs used on modern rigs, once set up mark the position of the hook to which the halyard is attached so that you can repeat the setting.

    To repair you sail a trip to any local sailmaker for a patch won’t cost you much, have a look on eBay there are often old sails offered for a reasonable prices.  I have sold several sails that way.  Any other GPs at your club? Most racers have old sails in the garage or shed that they want to clear out as they are past their racing best but which have loads of life for cruising.

    Steve

  • #17531

    steve13003
    Participant

    Just looked on eBay there is one mainsail on offer for £78, I would aim to pay about £50 for a used mainsail.  A repair should cost you between £10 and £20 for a simple patch

    Steve

    • #17532

      cookie
      Participant

      Hi Steve,

      Thanks for the great advice… But as you might have guessed I have a few questions for you if you wouldn’t mind sharing?

      When changing to a new tensioning system you will also need to change to a wire halyard for the genoa

      How is that done?

      Use of a cascade system or a muscle box for tensioning the genoa.

      How is this retrofitted to my boat?

       Sail eBay there is one mainsail on offer for £78.

      Yep looked at that one myself but its got as many holes as mine.  I’ve also looked on the classified section of this site and there seems to be about 4 adverts that seem to be well out of Date… Oliver, if you catch this post aren’t these adverts removed when old?

      Steve, thanks again for your advice. I will go for the pulley system it seems that it will suite my needs better and be safer and I’m sure there is advice on this site with regards to changing the halyard and retrofitting a pulley system.

      Dave

      • This reply was modified 3 weeks, 4 days ago by  cookie.
    • #17536

      Oliver Shaw
      Moderator

      Good point about removing classifieds when they are out of date.

      It is not my personal area of responsibility,  but I suspect the answer is that “we” rely on advertisers telling us when items are sold or withdrawn and the adverts can be removed.

      But perhaps we need a system to flag up when an advert is considered to be “old”.   Then,  of course,  we also need a specific individual tasked with regularly monitoring that,  and removing the old ones;    and almost all of us are volunteers,  and already fairly hard-working!

      I would expect that Chris will also pick up this point,  and perhaps Ann,  and that between us all at least one of us will follow it up.

       

      Oliver

  • #17535

    Oliver Shaw
    Moderator

    Changing to a wire halliard:    not in fact essential,  but it might be beneficial.      Undoubtedly you will need a reasonably low stretch halliard,   so the absolute minimum material is pre-stretched polyester (what used to be called pre-stretched terylene);   dyneema or spectra would be better,  and would be almost as non-stretch as wire.

    When Highfield levers first came in,  in 1969 if memory serves correctly,  rope halliards were fairly commonplace,  and the preferred material (the best one available at the time) was pre-stretched terylene.    This was sufficiently low stretch to work satisfactorily with Highfield levers,  but obviously wire or such newer ropes as dyneema or spectra will be better.

    If changing to a wire halliard you will need to know the required length,  for which you will need to measure up your existing halliard.   It is almost certain that this will not be the same as the “standard” modern wire genoa halliard,  because on the modern mast the genoa halliard exits the mast downward,  from just below the gooseneck,  whereas on your early boat I would expect it to exit upwards via a turning block at the bottom of the mast.   In either case,  the wire halliard will terminate in a large loop (a soft eye splice),  to which a rope tail is spliced on,  and that wire loop is hooked onto the Highfield lever.    I would suggest that you fit your Highfield (or alternative tensioning system if you decide to go with Steve’s advice,  which I concur with provided you limit the tension in the way he suggests),  then hoist and tension the genoa using your rope halliard,   and then mark the halliard where it meets the tensioning device.    Then when you take the halliard off you have a marked length of halliard,  and you can get a new wire halliard made to that length.

    It is possible that you may need to change the sheave at the base of the mast in order to provide sufficient clearance for the Talurit thimble of the eye splice to pass.    But try it with the existing sheave first;   you might get away without changing it.

     

    Oliver

    • This reply was modified 3 weeks, 4 days ago by  Oliver Shaw.
  • #17538

    steve13003
    Participant

    First a question does your genoa halyard run don the middle of the mast? or does it run in the sail track  with the bolt rope for the mainsail.  Some of the IYE (Gold) masts had the halyard in the mast and some had it in the groove.  Which ever position your halyard runs in I would suggest that you set up your tension system to pull down not up.  To do this if your halyard is in the middle of the mast you will need to cut an exit hole about 25mm below your gooseneck in the web of the mast, do this by drilling a top hole with a 10 or 12mm dia drill and second hole about 50mm below the first, then join up the holes with a small metal saw and file all the rough edges smooth.  Using a small hook, a bent coat hanger, fish out the genoa halyard from the centre of the mast.  The fix your tensioning HI field below the opening but with the lever above the mast gate. you can then hoist your genoa and work out how long it needs to be.  Normal is to have a hard eye and shackle to attach to the sail and as Oliver says a soft eye to attach to the HI field or other tensioning system.

    I have a large number of pictures and sketches showing how to go about setting this and other controls up, they are mainly on various series 1 wooden boats i have owned but the basics can still be applied to you Mk11 glass boat. If you would like me to send you copies email me at scorbet@btinternet.com as they are too big for the Forum.

    Just looked in my box of old bits and have found an old but serviceable muscle box, yours for the postage, just needs new forged hook – available from most chandlers.

    One final word of warning – have a very good look at the condition of your mast around the genoa halyard top sheave box – the IYE masts were very prone to corroding and cracking and then failing at this point – I had two IYE masts fail in this way – now more than 20 years ago but on masts much newer than yours may be!!

    Steve

     

  • #17539

    steve13003
    Participant

    If you look on eBay there are some blocks Holt Allen which would make good turning blocks at the base of your mast for a cascade system using some 5mm Spectra rope.  There is also a ball race halyard sheave and box which would be a good replacement for what ever you have in your mast – probably a composite plain bearing sheave.  All you would then need is a block and hook for the top of the cascade.

    Here is a file with some simple set up sketches.

    Steve

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    • #17541

      cookie
      Participant

      Hi Steve,

      You and Oliver have given me plenty of really sound advice and plenty of choices.  I think I’ll have a go at fitting the muscle box, a bit more work I know… Oliver you’ve scared me off the HI Field… ;0)

      [S]First a question does your genoa halyard run don the middle of the mast? or does it run in the sail track  with the bolt rope for the mainsail.

      I believe it runs in the sail track as I can see both (yellow and red) halyards through the slot where the mainsails bolt rope is guided.  Both halyards pass through a pair of guide wheels near the gooseneck and another pair at the heel of the mast. The red halyard is for the genoa and is cleated to the centre board casing, with extra tension achieved by means of a tooth rack also mounted on the centreboard casing.

      [S]Pictures and sketches showing how to go about setting this and other controls up and old but serviceable muscle box, yours for the postage.

      I would be very interested in the picture and sketches and muscle box steve. That very kind of you to offer. I will contact you on the email address provided and provide details.

      [S]IYE masts were very prone to corroding and cracking and then failing..

      I will have a good look at the mast on sunday when I go down to the club, but I’m sure its okay. Its a gold IYE.

      Thanks very much

      Dave.

      • This reply was modified 3 weeks, 3 days ago by  cookie.
      • This reply was modified 3 weeks, 3 days ago by  cookie.
  • #17598

    David Gilbert
    Participant

    Genoa Halyard Tensioning

    Some comments on the previous posts:

    • If the Genoa halyard runs in the sail track, then a normal wire halyard can “escape” the track and may jam the mainsail bolt rope, and/or may damage the sail. Fix is to use a thicker wire, or better still a plastic coated wire halyard.
    • I really don’t recommend a high field lever, and especially one that clamps to the back of the mast section. They are downright dangerous to the fingers, and are impossible to clamp securely, without resort to riveting a strap across the frame. (The same comment applies to the standard IYE sliding gooseneck – should be replaced with a riveted fixed fitting.) And sooner or later, the Genoa sheets will loop over the lever, usually at the most inoportune moment!
    • Muscle boxes or multi purchase devices may well be capable of over-stressing the boat, but you don’t have to pull the living daylights out of them.  The convenience of such a controllable device is much preferable to an over-centre device like a high field lever. On my last IYE mast I used the sheaves at the mast foot to form a multi purchase block arrangement, while on the later masts with the halyards inside the mast, it is convenient to bring out the halyard through a low-down slot in the mast wall, and then use a muscle box riveted to the side of the mast. I suggest you do not cut slots in the mast in the gooseneck region – that is a high stress area, and avoid fittings (including a high field lever) between the gooseneck and the deck, because they will damage the Genoa.

    I can provide a sketch of the above if that helps.

    Regards

    David Gilbert

    • #17599

      cookie
      Participant

      Hi Dave,

      Good points.

      After receiving the diagrams and sketches from Steve I changed my mind with regard to the muscle box solution and opted for the multi-purchase option instead.  It seems simpler and easier to set-up and operate.

      The Genoa halyard does run in the sail track although I was mistaken about how it runs. There isn’t a pair of sheaves just under the goose neck as I previously stated. There’s only a pair towards the foot of the mast.

      I was going to replace the original Genoa Halyard with – 9m x 5mm D Racer. Low stretch dinghy dyneema rope SK78 with hard eye at one end for the hook of the pulley system, however I didn’t  realise that the rope would pull against the main sail bolt rope and could possible escape.  Maybe this is true for wire but not so for 5mm rope?

      I was then going to attach the Genoa Halyard Tail with – 2m x 3mm MARLOW EXCEL PRO ROPE Low stretch Polyester core and exit at the base of the mast as before.

      The gooseneck hasn’t given me any problems so far, apart from the odd occasion when its come loose because I haven’t tightened it properly.  Do like the circular neck for reefing though.

      Yes. The High Field is out. I do like my fingers and I don’t like pain very much either!

      I will not be cutting into my mast at all. I was hoping to terminate the halyard with an hard eye just below the gooseneck where the track widens. Then attach a block with hook and Becket which then connects to two blocks either side of the mast thus keeping all the downward force on the mast.  Then travelling out to floating block as per Steve’s sketch.  however if you think this may cause the halyard to jam the mainsail bolt rope then maybe I should look at exiting from the heal of the mast and come up with a different muli-purchase configuration. Difficult to know where to fix blocks and cleats on fibreglass centreboard case ?

      Another question is to do with choosing the correct blocks?

      I’m not sure which blocks to choose, there’s so many to choose from.  If I’m to load the rig with 200lbs (91kg) then what spec blocks do a get?

      I guess the sheave needs to be able to take 5mm rope and the working load has to be about 2x91kg?

      Allen Dynamic 20mm Block Hook A2021HK  @ £13    165kg breaking load Doesn’t have a becket but has through hole so that you can thread a rope becket. or

      Allen 38mm Wire Hi Tension Single and Becket A4396 1000kg breaking load @ £38? and buy hook separate

      Rwo Nova Plain Bearing 19mm Micro Single Block and Becket R7102 Breaking load 570kg? I’d prefer this as its only £6 ;0)

      What size are the other blocks?

      Rwo Nova Plain Bearing 28mm Single Cheek Block R7206 for the mast blocks

      Thanks

      Dave C

      • This reply was modified 2 weeks, 4 days ago by  cookie.
      • This reply was modified 2 weeks, 4 days ago by  cookie.
  • #17614

    cookie
    Participant

    Hi Guys,

    With Steves help I’ve now bought all the bits I require for the modification.  I’ll complete this post by publishing photos and parts list for anyone else who comes this way. Thanks again to all who gave advice and special thanks to you Steve for taking the time to review my shopping list and for finding the blocks on ebay for me.

    Regarding the sails.. David Morris, Cpt Of the Gp14 fleet at my club, Budworth Mere, has provide a good set for me at reasonable price.   So it looks like I might just make the start of the season after all.

    Thanks again all. :o)

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