Two different gaff rigs .

[PeterSibley]

The two sail plans below are very different .Andrew Craig Bennett's Mirelle (I sincerely hope Andrew does not mind me posting it !) and an unnamed British cutter from the 19th century.

They are both aesthetically pleasing but I have such a poor understanding of the merits of one versus the other that I feel I need to ask the panel .

The earlier rig is notable for the relatively short length of it's spars ,something that interests me for a very practical reason ....they would be much easier to both log from the bush and then to handle and ship .It also has a topmast that can be lowered ,it's foot reaching the deck while it's head is contained .

There was an excellent discussion of topmasts and Mirelle's rigging sometime ago in which merits of pole masts were expounded upon .
http://www.woodenboat.com/forum/showthread.php?t=14420&highlight=topsail
I wonder if this could become some kind of a continuation ? With some explanation of the merits of both rigs ?

http://pic40.picturetrail.com/VOL282/9443996/17245530/330954375.jpg

http://pic40.picturetrail.com/VOL282/9443996/17245530/330953575.jpg

[soba]

I'm no pro, but it seems there are two very different rigs here...

The first one is a yachting rig, with a high (compared to #2) aspect rig...short spars and simple. It looks as she could be sailed with a competent couple...lots of leverage on the gaff for raising the sail, and a boomed jib for easy tacking. For ocean cruising, you'd probably see her with a small mizzen for balance and steerage. The smallish staysails would be relatively easy to handle. Best of all, there would be a minimum of running rigging (for a gaffer). The main disadvantage of this type is the stress that is put on the standing rigging as the wind climbs, which contributes to mast bend, making the sail fuller. Tensioning the rig to flatten the sail puts tension on the halyards...and well, you see where I'm going. Reef early with this rig, I says!

Design #2 has some great advantages...Usually the spars on these things were pretty light, as the rig can fail and the boat can still sail. So that comment about small spars is less telling. Not only that, but the bowsprit and topmast were routinely shipped when they weren't flying sail. You'd need a good crew, as there is a TON of spaghetti for running rigging, but the number of variations for flying sail makes it very versatile. I went for a short cruise on a smack that was similar in rig to this, and I noticed when they struck sails how easily she would lie to, I think because the mast and windage is pretty far aft. The short spars means she would be pretty dang stiff, and it's hard to imagine a knockdown. However, the light, flexy spars mean that the traditional gaff problems (sagging luff on the staysails) would limit how well she would go to windward. I'd want a vang on the main gaff and topsail. But she'd be easy to reef, and would drive quite well on just the main, or the main and a shortened staysail, I think. I'd take her in heavy weather, or for a lively livaboard.

Rig #1 is way way way less bother to maintain than rig #2.

I'm curious to see what the elders and pros have to say...

[TerryLL]

Hi Peter,

A few differences immediately stand out:

Mirelle is a pleasure boat and the British cutter is a working boat of some type, perhaps a pilot cutter. I suspect the differences in rig are in part due to how the boats were used, and the conditions they normally faced.

The cutter would be expected to sail the North Atlantic in any weather at any time of the year. Hence, a shorter mast and squarer main producing a lower CE, plus multiple options for shortening down, including the top mast that could be lowered while at sea. Also, Mirelle carries a self-tending boomed staysail, while the cutter's staysail is not boomed and could more easily be doused or changed out, another indication that Mirelle faced less firce conditions than the cutter.

There are also many similarities the two rigs share. They both carry lots of sail area for light winds, running backstays, boom-end sheeting, long bowsprits, double headsails, and topsails.


The cutter's rig reminds me of the short stout rigs used on the Colin Archer fleet of Norwegian rescue boats, and Mirelle's rig more closely resembles the taller rig found on essentially the same hulls, but fitted out as pleasure boats.

[Tom Hunter]

My not very well trained eye sees a rig designed for two in 1937 and a rig designed for four in the later nineteen hundreds.

I think the older will be somewhat more work to sail. That matters if the crew is not very fit, or if you don't have enough crew.

The older rig is clearly set up with the intention of riding out some very ugly weather. There is not as much emphasis on that in the 1937 rig.

Also, it seems to me that the topsail on the older rig is a very important sail in light air.

[Paul Stohlman]

The older rig is a large fishing smack, much larger than Mirelle.

The smacks worked in all weather, mostly in the non yachting season.

Other than getting to and back from the fishing grounds, they had to drag a dredge along the bottom (in the case of the oyster smacks) at a constant speed. The fishing aspects are well described in Michael Frost's books Boadicea CK213, and Half a Gale. Both are available from his grandson Reuben, who still operates Boadicea (http://www.boadicea-ck213.org.uk/). (No financial interest to me)

I think the relative scale of the rigs should be considered when comparing, in addition to the intended purpose.

[John B]

geez, how long ago was it I scanned that sailplan of mirelle? 2000... 2001?
What are you doing Peter.. thinking sail areas ATM?

[PeterSibley]

geez, how long ago was it I scanned that sailplan of mirelle? 2000... 2001?
What are you doing Peter.. thinking sail areas ATM?

John ,sail areas are roughly set ,sail shape is not . It's spar length that I'm looking out at this stage .I've always been interested in a reefable topmast mainly because it shortens the main mast length ,should I not wish to fly it .

I've got to wander off and cut the trees by and by so I can dry them .So lengths are necessary .

I'd be very pleased to have your comments on the sail plans above .

[John B]

There's no way I'd contemplate a seperate topmast Peter. Marconi mast with no topsail yard or pole mast with topsail yard.Maybe a jackyard if you want more area. Boom about flush with the stern, reefing bowsprit for berthage, main luff and head lengths about the same,gaff around the 30 degree mark and forget anything you've read about ' perfect proportions and formulas'...Every degree you give away from 30 to say 35 degrees off the luff lessens performance. Boom scantlings such that the sail can be loose footed and slab reefed without having to tie points( points are there for tidying up only)
Mainsail no bigger than 500 approx as 600 is a handful in rough conditions, Staysail as big as you can fit say 140 .. 150 ft at least and on a self tacking boom. Provision for headsails to be set flying or if you get a big genoa , hanked or on a permanent furler ( you won't want that I think;)).

As I probably said in that other thread( haven't re read it) I prefer that the topsail is a light air addition as opposed to a part of your normal working sail so this means your three lowers will work well through to say 20 knots and gives you power enough cruising in say 8 or 10.
At a guess 34...36 ft? boat ...that would be say 500 plus 150 plus say 180 to 200 for a working jib.. 800... 850 working. plus a topsail say 120.. 150 and a 400 ft genoa for light .
Thats what I reckon.:D

[PeterSibley]

Thank you John ! That's why I asked you :).

Just one thing ( you see I've been reading my Worth !), why no topmast ? He seems to drop the thing in heavy weather and remove it entirely for his British Winter .Certainly less windage and more flexiblity .

Peter

[John B]

Because you'll be flat out busy pulling more string than you can possibly imagine with a simplified rig Peter. To add anything to that just puts me right off. Plus all the extra rigging etc to house it , the added bulk even stowed , I'd argue that its a marginal saving anyway.
A pole mast is just a rig without a topmast and with a yard topsail. Go that way instead if thats a concern.
One thing to concentrate on. I've had long discussions with many people over an issue that often emerges with the gaff. The gaff will crank and cock up to windward at the saddle end on some points of sail. Its more common than you think. Some say that having jaws is the fix but that just treats the symptoms, not the illness. The fix is to have absolutely as much throw between the jaws/ saddle and the crane as you can have. So build that into your thinking when you design it.

[PeterSibley]

[quote=John B;1923251
The fix is to have absolutely as much throw between the jaws/ saddle and the crane as you can have.[/quote]

Can you give an optimum number for the size rig I thinking of ?...say Mirelle's rig. Peter

[John B]

Not really Peter. I had it on Waione with about 1 metre between the saddle and the crane but it went completely when reefed ,so at 2 metres. Its a function of halyard tension and length changing between closehauled and running.
What I'm saying is when you're choosing and you have discretion ( working around all the other works/ spreaders rigging etc) go higher rather than lower with the throat crane.
I also like to see the peak as high as you can get it too. Those drawings show such an acute angle that there's energy going into compression as well as clean tension the direction you want it. A bit like a vang at an acute angle to the boom creating compression loading on the gooseneck.
I went for a near right angle off the gaff... ,another argument for a taller mast section.

[John B]

You need a third rig up there to compare to, a Gartside say.

[PeterSibley]

Your wish .......the 30 footer

http://pic40.picturetrail.com/VOL282/9443996/17245530/331100304.jpg

[PeterSibley]

Now I know it's probably more efficient , but aesthetically I don't like it .
However I can see this point ,

"I also like to see the peak as high as you can get it too. Those drawings show such an acute angle that there's energy going into compression as well as clean tension the direction you want it. A bit like a vang at an acute angle to the boom creating compression loading on the gooseneck.
I went for a near right angle off the gaff... ,another argument for a taller mast section."

in the Gartside drawing .

[John B]

Tall rig on a short ended boat so yeah in sail plan form it might not satisfy some people aesthetics. But you can take cues from that, your boom will be longer relatively because of your counter and perhaps a tad less lift.. you'll be surprised how well it'll look.
But most importantly, perform . Performance is a safety function too you know.;)
And that peak angle I mention.. its just a guide but don't go throwing it away.. 30 ,33 degrees maybe 35 but keep every degree you can that satisfies you looks wise.

[PeterSibley]

John ,thank you for the education :) .

[PeterSibley]

John ,
in the top two drawings the gaff angle is 35 degrees ,it would be possible to gain a few degrees on that ,loose the topmast and extend the mainmast ,say 5 foot and use a Curlew style topsail ,while maintaining the appearance I like .I think from memory , my main will be around 420 square feet ..but I can't find my drawings right now .

What do you think of that ?

[John B]

Well, you have to draw it up, photocopy it onto paper and tracing paper( so you can have it pointing the other way), then pin it up in various places around the house and workshop where you least expect it ...like inside the wardrobe door for example ,and then when you glance at it unexpectedly like, you know whether you like it or not.:D

oh.. and you have to have it with and without topsail.LOL.

Sounds pretty good to me . I think Curlew ran a yard topsail incidentally. 400 ft is a doddle.
Have I talked you out of roller reefing yet?( sits back and waits for Andrew;))

[PeterSibley]

No. Roller reefing is the go ! :D