SetSail » Rigs & Rigging

Wharram style “soft wing sail” viability on a monohull

Steve Dashew — Tue, 23 Jun 2009 06:00:56 +0000

Hi Steve, I am designing a rig for a 42′ cruiser (monohull). Due to the nature of the hull I need a lot of sail area and a low center of effort. James Wharram, about 20 years ago, developed what he calls a “soft wing sail”. It is a gaff rig with the leading 1/4 of the sail made up as a sock which slides over the mast, in place of hoops, lacing, etc. It’s obviously efficient aerodynamically. My concern is that friction between the sail and mast could cause problems with reefing/dropping the sail. Wharram has been using the design now for decades and says that there is no problem, that it can be dropped on any point of sail. He has lots of boats sailing with this rig. It seems to me that if this works on a cat it should work on a mono as well. I’ve crunched the numbers on rigging loads and mast compression and these can be made to work. I’d greatly appreciate your thoughts any any experience you have to share on how this rig might work on a mono. Regards, Paul

Leading edge socks have been around for many years. We used a version of this on a C-class cat in 1968. They are efficient, but bring a lot of baggage with them in terms of reefing, friction, cost, and complexity. Some of the early free standing rigs tried to develop this approach, but ran into the practical problems above. If you are cruising locally, and into tinkering, might be an interesting project with which to play. But my feeling is that for a long distance cruising boat they are not suitable.

Furling Line Control

Steve Dashew — Tue, 30 Nov 1999 05:00:00 +0000

Can a ratchet block be used in order to control the release of a furling line? The 44′ boat I recently purchased uses a small diameter spectra line for furling, and if and when it takes off in a breeze, it can do great damage to the hands! If you let it go, it usually kinks in the aft furling block. Thanks, Ted

Hi Ted: A ratchet block will help, but in a breeze you will want a winch. And in light airs it will probably be necessary to turn off the ratchet when unrolling. Steve

Rod Rigging Fatigue

Steve Dashew — Tue, 30 Nov 1999 05:00:00 +0000

Hello Steve, I have a decision to make now on my new rig.

I have a brand new carbon fibre spar. It is 56′ long, double spreaders with discontinuous rod standing rigging.

The shrouds terminate with stemballs in the spreader bars (i.e. no tangs in the spar except for the cap shrouds).

The shroud stemballs cannot be removed while the spreaders are in place, which means that if I had a shroud problem, it would be impossible to change while the mast is standing.

Navtec has a part which is a stemball with a marine eye on the other end. This means I could have forks on the ends of the shrouds, which are pinned to the stemball eyes, which are embedded in the spreader bars. This would allow me to change a broken shroud while under way.

My question is: Should I bother? With rod rigging, are there signs of fatigue, like with meat hooks etc. in wire? If I broke a shroud, say a D3 or V2 or D2, or something, would the spar already be broken and changing the shroud is now meaningless? Obviously if a V1 broke, the mast would snap instantly, so we don’t have to talk about that. More clearly stated: is there any circumstance that would prompt me to want to replace a rod shroud while away from a harbour and a mast crane?

The stemball eyes would likely add maybe 2 or three pounds to the rig, and add the complexity of a dozen extra bits and pieces.

I want to sail across an ocean (and back) some time in the next few years or so. – Ryan

Navtec have fatigue indicating fittings, or they used to. I would not use rod without this. In general, I have not been a rod fan for all the reasons you mentioned. If you are crossing oceans, make sure they have higher than normal factors of safety. – Steve

Leaks via Mast

Steve Dashew — Tue, 30 Nov 1999 05:00:00 +0000

Hi Steve, Good articles on leaks…

I’ve never had mast collar leaks…but what I do have is rain water getting into the mast, I guess through the halyard exits etc., which accumulates in the bilge…any suggestions as to how to cure that kind of leak?? Cheers, Alan

What we do on all our boats is put a dam at the bottom, above the deck, via a trap door in the side of the mast. This catches about 95% of the rain/spray. – Steve

Roller Reefing #4?

Steve Dashew — Tue, 30 Nov 1999 05:00:00 +0000

Hi Steve, I’m ordering a #4 for my J120 which I intend to sail from the Caribbean back to the States this spring. The boat is set up for roller furling on the headstay.

My question: Does it make any sense to put reinforcement in the #4 so it can be rolled up to storm jib size? I do have a storm jib, but think it would be easier to set the trysail and the #4 when the wind gets over 25 knots, and progressively roll up the #4 as the wind builds. Easier — but impractical?

I’d be most interested in your comments. Love your books (I’ve got ‘em all). Cheers, David

Hi Dave: Tough question. I’d answer first by saying it depends on where you are sailing. If the sail could be set up right for heavy conditions, and if you were not likely to be using it for long periods, maybe OK (assuming of course the roller furling gear was bulletproof).

For sure it would be easier to just roll up the #4, assuming the shape was reasonable and that you had a proper lead for the jib. But those are big assumptions. Odds are you would need to start with a pretty high clew, and/or have a very long jib track or position on the rail to move the block to for storm jib size.

On the other hand, if you are going to be spending long periods reefed down to storm jib size, I think I would rather have a proper storm jib aboard, that could be set on its own stay. This would be especially the case where you will be using the system for beating (typically the ultimate heavy weather tactic).

I am going to forward your question to Dan Neri at North and see what Dan has to say. Regards – Steve

Slab Reefing

Steve Dashew — Tue, 30 Nov 1999 05:00:00 +0000

Hi, I’ve just purchased a 1975 Westerly Centaur (and yes, I don’t plan on getting anywhere quickly). The boat has its original rigging including a roller-reefing boom. I would like to employ some sort of basic slab reefing type approach, but there are no reef hooks and there doesn’t appear to be an blocks on the stern end of the boom for running lines to the clew of each reef. Can I just mount all of this on the present boom and run appropriate lines? If I can mount such hardware, would I rivet it onto the boom? Or do I need to think about a new boom (I really don’t want to buy a new boom). Thanks! – Arthur

Hi Arthur: Slab reefing is easy to do. Usually a new boom would not be required. The blocks should be bolted, not riveted. And of course you will need some reef clew/tack cringles put into your mainsail.

There is some information on slab reefing in our Offshore Cruising Ency. And you will also get some good input from your local sailmaker.

Be sure to coordinate the location of the reef points in the sail with where the hardware goes.

One issue to consider with the boom. In theory, roller reefing evenly distributes the sail load along the boom (reality is usually something different). Slab reefing will point load the boom more than the roller reefing. In most cases, the boom would have the beef to handle this. But it is something you might want to get a rigger to take a quick look at. Regards – Steve Dashew

Single Line Reefing

Steve Dashew — Tue, 30 Nov 1999 05:00:00 +0000

Dear Steve, We are building a 46ft cat for live-aboard offshore cruising and have been studying and contemplating your writings with relish…We are ready for rig quotes and have been considering single line reefing – mostly to reduce the number of lines in the cockpit. Our last cat had simple slab reefing with luff & leach lines returning to the cockpit, and it worked very well.

We are concerned about adding complications and are unsure how to do it so, & that if anything goes wrong inside the boom we can fix it easily. Most people we have asked have thought it was OK in smaller boats, but weren’t confident to recommend it for as powerful a rig as ours.

Our cat is ‘a mainsail boat’ with 75sqm main with big roach like Beowulf, and self-tacking jib.

I am wondering if you could tell us how you set up single-line reefing in Beowulf and whether you have any more information or impressions that would help us.

Best wishes with your new project. – Sandy S

Hi Sandy: I’m of mixed opinion on single line reefing. I have tried it myself, and seen it used on other big boats. A couple of issues to consider:

1-I would not put the lines inside the boom if there are any tackles involved. If this is just a single line running from the clew forward, it is OK. However, be sure to have a couple of messenger lines to use if the line fails.

2-Set up the system so you can change back quickly – at sea – if the need arises.

3-Be sure to work with a sailmaker who has experience in single line systems on boats of similar loads. This adds a lot of load to the luff of the sail and needs to be dealt with in terms of structure and angle very carefully.

Having used both, my preference for big loads is slab reefing with separate clue and tack. This offers more flexibility and less hassle with the main. But, as you have pointed out, more clutter in the cockpit. – Steve

Fractional Rigs for Cruising

Steve Dashew — Tue, 30 Nov 1999 05:00:00 +0000

Dear Steve, Thank you for taking the time to read our email. We are selling our home to buy a yacht to cruise the oceans to enjoy our time together. I’m a marine mechanic specializing in power boat refits. I have limited sailing experience and Karen has even less.

We are currently shopping for a yacht with the intentions of learning on the boat we will be cruising on. We have your books and recently purchased a video you appear in (Heavy Weather Sailing), we found it all very exciting and informative. We are planning on spending the next year or three learning and doing all the necessary courses to become competent offshore sailors.
The yachts we are looking at are mainly masthead rigs but we have come across a fractional (Farr 1104) which shows a lot of potential as a cruiser/live-on.

Although you suggest water length to be main consideration, this is the largest within our price range. I am aware of the sailing differences between fractional and masthead after reading your books, but I have no experience sailing on fractional rigs and am not sure of the difference of rig strength.

The type of yachts we are looking at are:

Duncanson 35′ Masthead
Northshore 33′ Masthead
Farr 36′ Fractional

Just once again thank you for your time and valued advice. – Alen S

Hi Alen: Sorry for the delay in replying – been away flying my glider. Re: fractional rigs, they make great cruising boats if you can handle the main, and are usually easier to sail than masthead rigs because of the smaller headsails. Also, you can often sail under main alone. The key thing is having a good reefing system, and making sure the boom and sheets are set up so as not to be dangerous in an accidental jibe.

Structurally, the same basic rules apply and a fractional rig can have high factors of safety, or low factors of safety. I’d contact the Farr office and ask for their input on the design you are considering. If it is a runner-dependant rig, i.e. one in which proper operation of the runners is required to keep the mast from collapsing, then you might want to look at something less tricky. But many fractional rigs are not runner dependent. Good Luck – Steve

Using a Roller Furling Headsail Upwind

Steve Dashew — Tue, 30 Nov 1999 05:00:00 +0000

Hello, In your rigs and rigging section, you mention using the Profurl 4000 free flying furler. Can that furler be set tight enough to work for use up wind sail?

Don Street, in his valuable book The Ocean Sailing Yacht, mentions his using a similar unit some years ago for both jib and staysail and using them upwind, downwind, whatever. High luff tension is vital, of course. I don’t see why these couldn’t be used for all headsails, providing the safety of being able to get the sail down and also being able to easily change sails. Leaving the headstay would provide the backup system for a hanked-on sail. The century-old Wykeham-Martin design still works well for gaff riggers. Can the new flying furlers fill the role for Bermudan rigs?

Thanks, Donal

Hi Donal: There is no easy answer to your question. This depends on how strong a wind you want to use the free-flying furler in to weather, how much headsail sag you can tolerate, and the structural capability of the mast and sprit or stem to which things are attached.

The problem is not the furling gear per se – you can always get that strong enough. It is everything else in the equation. Race boats do use these sails upwind in light airs. We could carry Beowulf’s free-flying reacher (cut flatter than the code 0 we had aboard) in up to six or seven knots apparent – after which it was better to set our regular jib. This was using two-to-one spectra halyards. We looked at a higher wind range, but did not want to subject the mast and bowsprit to the higher loads which would go with trying to keep the luff straight. – Steve

Halyard Brake for Use with a Furling Boom

Steve Dashew — Tue, 30 Nov 1999 05:00:00 +0000

I am installing a small electric anchor winch to hoist and reef my boom furling main, which has a large roach. I would like to have a halyard brake or other device to maintain light, constant tension on the halyard as I haul the sail down to reef or stow completely. If tension varies, the roll loosens and risks jamming against the front of the boom. Who makes such devices, or can one find a rope clutch that has a variable setting that could be used? I don’t care what it is called, only that it does the job I require…Thanks….Lowell

Hi Lowell: I have not seen such a brake before. However, I would check with the guys who make the inboom furling systems as they might have developed something like this. Regards – Steve