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

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

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

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

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

Oliver

The set up you have is typical for all types of through deck sheeting used on fibreglass boats from all manufactures.  The recommended sheet diameter for through deck sheeting is 6mm, but my crews find that although the 6mm rope runs through the bocks it is not very kind on hands!!  8mm sheets are nice to handle but dont run through without friction in the blocks, so we compromise with 7mm sheets which do run through and are easy to handle.  If you want to use 8mm sheets you should consider changing the lazy block for a larger size to give the rope more room.  My current SP1 boat has 20mm lazy blocks, when I fitted through deck sheeting to my Series 1 Duffin I used 37mm Harken blocks to allow the 8mm sheets to run with minimum friction.

• This reply was modified 10 months ago by Oliver Shaw. Reason: Typo correction

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

Oliver

It looks to me as if the mounting block was originally mounted further forward. I think It’s pulled off and been reglued in a different place. This was far from uncommon on the Speed hulls, access is a total pig and to be honest the whole system isn’t very good. The new boats are far better – but this doesnt help you!

I think I’d probably want to check the line before buying larger blocks. Make sure that the lead is clean and mock up from what looks to be the original position. If it looks like the run off the lazy block is wrong the only real solution is to move it – bigger blocks wont help. If anything the run needs to be in front of the moveable track. Best done with the boat upside down. A sharp chisel and firm tap should get the pad off, tufnol doesnt glue very well.

• This reply was modified 9 months, 4 weeks ago by Chris. Reason: spelling/autocorrect disaster!