Mast Top Arrangement

[MarkF]

I’m hoping someone can cast a wise eye over the slightly odd main mast-head setup on our gunter BR20. Photo attached shows:

Thing 1) it’s rigged for a spinnaker, but the wrong way round. Jib halyard runs over the small pulley. I assume it was done to allow spinnaker to be gybed easily, but I don’t like the halyard curving over such a small angle.

If I swap them back, will I find it hard to gybe the spinnaker, or will it cross over the top of the jib stay without a problem?

Thing 2) washers. Lots of washers. Piled onto the jib block shackle. I assume it’s to keep the shackle pointing the right way to avoid it getting twisted. But unless spot-on it will exert a bending moment on the mast attachment. It seems superfluous and a Bad Idea, to me. Any opinions, please?

[Graham W]

Mark,

If you look at photo 4 in the owner’s manual in the library, you’ll see that the shackle securing the fiddle block has the same washers as you. https://www.swallowyachtsassociation.org/wordpress/wp-content/uploads/BayRaider-June2010.pdf.  It’s the same with the shackle holding the top of the shroud.  My washers are still up there and I haven’t noticed any adverse effects in the past thirteen years.

However, you’ll also see that the manual says that the jib halyard should run over the larger of the two sheaves, which means that the spinnaker halyard runs in the smaller sheave underneath it and might interfere with the jib halyard under certain conditions.  I always thought that this was a bit odd and changed my topmast arrangement to a double (side by side) block during my first season.  This then morphed into two separate blocks with some physical distance between them after I installed a halyard crane up there.

[MarkF]

Graham,

Thank you - terribly embarrassing to ask a question where there's even a picture to show intended installation.  Note to self to check the documentation more thoroughly next time!  I have upgraded my pile of washers to being a Good Thing.

I had read the posts about separate spinnaker blocks, but I don't see an easy way to install that on a carbon mast. I'm very reluctant to drill holes into it. I could almost do with a fiddle block with two large pulleys and but the jib halyard on the front one of those.  Not that I can find such a thing for sale. Attaching two separate ones together in series could solve the issue, whilst introducing yet another joint in the system.

[Graham W]

The topmast plug with the dumb sheave and stainless bracket attached to it doesn’t look like it’s made of carbon fibre.  In one of your photos, some black paint has flaked off it, revealing what looks like sapele wood or similar underneath. 

It’s possible to attach a halyard crane to the topmast without drilling more than one extra hole, as Guy Rossey did in the attached photo.  I copied his idea, although I found it necessary to reinforce the arms of the crane as they sheared off on my first attempt.

[Sea Simon]

Graham,
 Attaching two separate ones together in series could solve the issue, whilst introducing yet another joint in the system.

Meanwhile, I'd  mouse/seize those shackle pins...gents 

[MarkF]

Thanks, both.

Yes, I will be seizing anything in sight once my monel wire arrives!

I think the top plug of the mast is wooden (hopefully no longer the mast-splitting type).  I will probably try some alternatives before drilling into anything.   

Out of curiosity, why did you move away from a side-by-side arrangement of blocks?  Did the sails still interfere/struggle to gybe?  I saw a tripple block, which would mean the jib could occupy the central roller, keeping the main load central, with the spinnaker on one side.  Seems a bit ungainly as the third roller would only be useful for hoisting up washing or the like.

[Graham W]

The side-by-side block idea was for when I just had a spinnaker.  Then I branched out with a plank bowsprit and flying jib on a furler.  And quite a bit later a code zero on a continuous furler.  Both of these needed separation from the jib furler to avoid entanglement up top and side-by-side blocks didn’t provide this.  I think that I had a triple block with the jib on the central sheave to avoid imbalance up top. One side was for the spinnaker halyard and the other was for a jib boom topping lift for light winds.   The big ungainly block wasn’t really necessary and in any case I then moved on to something even more complicated.

[MarkF]

... I think that I had a triple block with the jib on the central sheave to avoid imbalance up top. One side was for the spinnaker halyard and the other was for a jib boom topping lift for light winds.

Graham, did the triple block work?  From reading previous posts about the jib topping lift, it sounds like using the spinnaker halyard for this is acceptable, but can stop the self-tacking jib from changing sides freely, so I was wondering the same issue exists using a dedicated topping lift over the third roller?

I think I'll first try out the spinnaker with our current arrangement and see what sort of mess we end up in!

[Graham W]

The triple block worked, more or less, but was big and heavy and in the end the halyard crane and two separate blocks did a better job. 

Using a block for the jib boom topping lift wasn’t overly satisfactory and it is now attached above a parrel bead which is above the jib top furler.  It is adjustable down below using a Clamcleat arrangement.  Works a treat.  See here for more details https://www.swallowyachtsassociation.org/smf/index.php/topic,1217.0.html.

[MarkF]

Thanks, Graham. I’d read about your rather snazzy arrangement and intend to emulate it. A couple of questions, if I may:

* What diameter is the top high-load eye? Small 16mm? so it’s just wider than the rope?

* What diameter is the rope? 4/5/6mm? I assume it’s not dyneema?

* Is the rope spliced directly onto the eyes?

* is the lower high-load eye much bigger to give the rope a bigger diameter bend? 22mm?

* what’s the size of the screws used to attach the guide under the boom? I don’t want to be over zealous and split or weaken the wood.

* and, err, what’s the black guide thingy with the hole in screwed to the boom called? I’m not sure what to order!

Many thanks.

[Graham W]

Down in Cornwall at the Mylor raid at the moment.  Because of the forecast, which turned out to be accurate, I removed anything to do with fair weather sailing, including the topping lift.  I’ll try to answer next week.

[MarkF]

Thanks, Graham.
Hope the Raid goes well. Your weather looks impressively bad! I’d probably opt for sitting in some once-used-for-smuggling hostelry to spend the day talking about how adventurous the sailing would have been had I gone out. But that’s not a very Raid spirit!

[Graham W]

Mark,

The rally conditions were a bit challenging for the smaller boats but compulsory water ballast on all three days meant that there were no capsizes, unlike last year.  Quite a few breakages though.

The top and bottom high-load eyes of the jib topping lift both have an internal diameter of 12mm.  The top one is sufficient to hang off the 8mm jib halyard, supported underneath by a 45mm external diameter parrel bead which rests on top of the top furler.  The bottom eye is bigger than needed but was probably what I had in my bosun’s box at the time.

The line from the top eye to the top of the CL253 Clamcleat is 4mm Dyneema, spliced around the top eye and to the top of the Clamcleat.  The line forming the adjustment mechanism through the Clamcleat appears to be 5mm polyester braid - Dyneema would be too slippery for this purpose.  The bottom sling part of the arrangement is again 4mm Dyneema, spliced around the bottom eye and formed into a long soft shackle.

The black bullseye fairlead that I screwed under the jib boom may be unnecessary - I now just loop the sling line under the boom and rely on the rubber doorstop under the end of the boom to stop it from slipping off.  That means that a long loop might do the job of the sling just as well as a long soft shackle, as there’s no need to undo it to thread it through a fairlead.  I should say however that since I originally installed the topping lift, I've changed the jib boom from rectangular-section wood to a rounded carbon fibre spar, with less chance of abrasion.

Good luck!

[MarkF]

Hi Graham,

thank you so much for the excellent information.  I will get ordering.

It seems I'll finally have to learn to splice Dyneema.  I guess it's inevitable, along with death and taxes!

One thing you mentioned made me wonder - you'd said you removed your jib topping lift for windier sailing this week.  I assumed it would be particularly useful in this case.  If, in the worst conditions, you opt for double-reefed main,  I'd have thought the jib topping lift would allow the shroud tension to be maintained when most needed?  Or does it just get in the way a bit?

[Graham W]

The self-tacking jib has a particularly taut leech when the jib outhaul is pulled tight enough to get the aft end of the jib boom off the deck.  In very light winds, this is less than ideal because you need to be able to form a fuller sail with a more relaxed leech.  This is where the topping lift comes in.  It works and it's witchcraft!