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Hi Guys,
The mast step in my 1972 GRP MKII GP14 (thanks Oliver) is a bit passed its best and I was considering replacing it. Can anyone advise on the procedure for removing and refitting please. I have a nice piece of Oak and a router that I could fashion a new one out of.
Thanks again
Dave.
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Replacing like with like should be fairly straightforward, and from memory Steve White documented this photographically a few years ago on the GP14 Owners Online Community site.
I confess that I started to reply, having misread your post, thinking that you wanted to do the mast step conversion, which is most usually done either to address hull weaknesses or to permit modern rig tensions. Modern rig tensions are vastly higher than the boat was originally designed for; the technology to produce them simply did not exist in 1949 when the boat was designed.
I now realise that that is not what you were asking about, but if you are going to do some surgery anyway it is perhaps worth considering, although less pressing than in a Series 1 (i.e. wooden) boat of similar age. What follows is specifically for that conversion, and not for a straight like for like replacement.
The only case which I personally am aware of where this conversion has been done in a GRP boat is one which (around 10 years ago) was at Neyland Yacht Club. If you wish to pursue this you might think it worth contacting their GP14 Class Captain to be put in touch with the owner concerned.
Otherwise use your judgement, but aim to preserve the original location (in plan view) and probably raise it a bit and use structural (e.g. solid mahogany) filler pieces underneath in order to be able to spread the load over a good long length of the keel and perhaps also the frame that is immediately forward of the centreboard case. If you can also strongly bond the structure into the case itself as well, that will further help to spread the load.
The official mast step conversion for wooden boats raises the step by the exact amount corresponding to the difference in length between the Series 1 and Series 2 mast, and changes the step for the track (and tenon in the mast foot) as per the Series 2, so the Series 2 mast then fits. If keeping the old Series 1 mast it is a simple matter to cut off the required length and just change the foot. For the sake of future interchangeability of masts I would suggest that it would be worth working to that specification.
From memory the amount you need to cut off the old Series 1 mast is 12 cm, but do please check; I stress that I am quoting from memory only. The mast lengths can be found in the Class Rules, which are in the Members Area on this site.
Hope this helps,
Oliver
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Hi,
I have now removed the mast step which comes in two parts. The top section is made of 22 mm plywood and is fixed to a mahogany plate with 4 screws it has a rectangular hole cut into it to accommodate the heel of the mast. The heel of the mast sits on the plate which is bolted to the hull with two bolts. The studs that take the nuts are themselves bonded to the hull.
The top section was rotted but was complete enough to use as a template for a new on that I have made from a spare piece of oak I had. The bottom section is still serviceable although after drying it out the mahogany is showing cracks in various places along the grain. Having said that the structural integrity is still in-tacked. The mahogany plate has an 18mm plywood strip glued to the underneath section. The ply makes contact with the hull and most times is sat in water as there its getting in from somewhere. (The centre board casing pivot bolt was lose so maybe from there)
I intend to apply epoxy to the Mahogany mast step plate for now and look to replace the whole thing at the end of the season. One note on replacing this part is that it has been machined out of a solid piece of Mahogany with the underside chamfered to prevent the otherwise square profile from pressing into the hull.
One question remains when I come to do this job is what adhesive should I use for fixing the new ply strip to the underside of the step plate?
Oliver, Thanks for taking the time to reply to this post… I did attempt to find an appropriate post from the archive before asking this question but I couldn’t find anything. Likewise I cant find Steve White’s document or photos. I must be searching incorrectly so apologies for repeating a question that has been answered many times. Any advise on using this forum to find information would be greatly received
Thanks
Dave
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Oliver is right – and remembered correctly that I did this to 9121, and documented the shape and the dimensions of the mast step. I’ve copied this from the GP14 Owners Online Community site where I posted this in 2014. It’s in the photo album 13292 (which is a FRP MKIV, and please don’t ask me how Yahoo does it’s thing).
<span style=”caret-color: #555555; color: #555555; font-family: ‘Source Sans Pro’, sans-serif; font-size: 12px;”>> One question remains when I come to do this job is what adhesive should I use for fixing the new ply strip to the underside of the step plate?</span>
Epoxy or Polyurethane Foaming Glue are both fine for this – note that Polyurethane Foaming glue only has strength if the parts fit tightly and are clamped tightly. I hope the diagram helps – the complex shape was too hard to draw, and my guess is that each boat is different. If I were to do this again I’d lay the mast step on a thin sheet of solid neoprene to make sure that the surfaces between the complex shape and the hull mated evenly.
I hope this helps.
I found the original posting – I *do not* have the dimensions – I recreated this diagram from memory, but I believe that there is value in seeing how the part is assembled from three layers of 18mm ply, and that the dimensions can be roughly got from the rotted remains of your mast step. If you have the measurements please add them to this posting.
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<span style=”color: #555555; font-family: ‘Source Sans Pro’, sans-serif; font-size: 12px;”>Steve and Oliver,</span>
Thanks for this it’s just the info I need. For now I have dried out and treated with epoxy the original part which measures up to the drawing Steve has kindly provide. The mast step assembly now appears to be sound after treating with epoxy and will last the summer out. I will use the information you’ve provided to machine a replacement at the end of the season.
While she’s been sat on my drive I have renovated all the wooden parts sanding and re-varnishing… The old GP looks as good as new… well almost.
I’m taking it to Budworth Mere tomorrow where I’ve just become a member.
Thanks again
Dave
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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
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It would be a pleasure to meet you Oliver and you’d be very welcome at the club… Maybe in the Autumn then?
I took to the mere for the first time on Friday, single handed, (Cruising NO Racing) and it was beautiful. Glorious sunshine and a nice steady breeze with a nice beer to round off the evening… who could want for more!
Well there’s always something isn’t there… Any idea why I’m getting a constant trickle of water dripping from the top of the centerboard case the end towards the stern?
I take on about 1 litre per hour.
Kind regards
Dave
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Water dribbling from the top of the centreboard case: I don’t reliably remember the construction on that model. Do you have a wooden capping piece, and is the water dribbling from underneath it?
If so, the capping is probably screwed in place; unscrew it, clean up, and refit, bedding it down onto a suitable sealant.
Silicone sealant will serve, but if you get any onto your varnish and fail to completely remove it before it cures you may then find it inordinately difficult to remove it later, and future varnish won’t adhere on top of it.
Better might be a polysulphide sealant, and they are available at about the same price as silicone sealants. Alternatively you could use something like CT1, which is a sealant adhesive, or HA6 which I have had recommended to me but which I have never used, or the appropriate grade of Sikaflex. https://www.marinescene.co.uk/view/4920/c.t.1-underwater-marine-sealant https://bond-it.co.uk/premier-range/ha6-rtv-silicone/
If the top of the case is bare GRP then it is a matter of identifying where the leak is, and then a standard GRP repair.
Oliver
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Oliver, once again your advice has proven invaluable…. I was imagining all sorts of horrors but following your advice worked a treat.
I had removed the capping to renovate it as all the varnish had become tarnished. Then I didn’t seal it when I replaced the capping. Now looks good as new and best of all NO leak!
Thanks again.
Dave
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