anybody know of a book that discusses rig proportions for gaff rigged working vessels

Hey there. I wanted to find a good book based around rig plans and proportions for traditional gaff cutter rigged European working boats. I am doing a gaff rig conversion on our cruising boat, a shortish heavy double ended fiberglass cruiser with a semi full keel (cutaway forefoot.) The boat is a Thomas Gilmer Design and not the first of this type to be converted to gaff rig.

I have worked in gaffers and square rigged training ships for the better part of the last decade and have all the usual literature, sailmakers apprentice, riggers apprentice, young sea officers sheet anchor and the like. But what I am more interested in at this stage is a more detail oriented book discussing actual rig proportions of european working cutters of the 19th and early 20th century, so that I can come up with a "Rough" rig plan, that I will then present to a naval architect for tweaking and discussion to get the centers of effort exactly right and the size of the rig properly suited to the hull.

The working rig will be fairly short, with no topmast, but with still enough light wind sail area to carry her in light airs. For light air work I was considering a Jackyard topsail, set from deck to extend the vertical sail area without a topmast, and so that when the topsail is doused you don't have the weight and windage of a topmast or a higher lower mast aloft. As well there will be a selection of headsails from a working jib to a high cut yankee, and a drifter that can be set on a traveller on the bowsprit. Will be a three reef gaff rigged main and a staysail with atleast one reef band for heavy weather.

The bowsprit is going to be built to be retractable as many of the working rigs of those days, and in heavier airs could be hauled inboard and secured while the mast remains supported by the heavy forestay attached to a stem Iron, while she runs or heaves to under the reefed main and staysail. Similar idea to the Colin Archer designed Norwegian rescue vessels.

I am debating between a tabernacle stepped mast or going the extra mile and keel stepping it. The more I research, the more I seem to find various tabernackle stepped gaff rigs on English working boats, it was something I hadn't considered before.

There will be three lower shrouds a side, running backs, an inner forestay set up to the stem iron and an outer forestay on the end of the bowsprit set up by tackles. All the running rigging is going to be around 10mm heat set dyneema, parcelled and served full length, with spliced eyes going over the masthead, leathered and set on bolsters. The lower ends will be spliced with over sized eyes and seized around deadeyes. Keeping in mind the mast may be stepped in a tabernackle the aft most shroud on both sides could be swept significantly further aft,

Going to have heavy duty bronze external chainplates for the standing rig, well backed and supported, researching the types of bronze people are using for home built rather than cast chainplates now..

Thanks

Ryan

I don't recall many books that specify line and wire sizes, but there are a couple that set out the sail plans and deck fittings.
What length beam and displacement is your boat?

Ohh, That looks like the ticket. Thank you. I can get that through Woodenboat?

LWL: 26' LOA: 33' Beam: 9.75' Displacement: 15000 Lbs

Shes a roughwater 33, basically identical to the Southern Cross 31, and there was another one.. Aries 32 I think the name was. All small ish heavy displacement double enders with a cutaway forefoot, moderate beam and fairly short conservative rig. The Southern Crosses were bermudian cutter rigged, the roughwaters sloop rigged but with the same mast position.

Her Waterline length, beam, displacement etc.. Are all very very close to the lyle hess 28' Bristol Channel Cutters. The Roughwater is 1000 pounds heavier and with slightly less beam, a few inches difference in waterline length.

http://<iframe width="560" height="315" src="https://www.youtube.com/embed/G0LEqpmx3tI" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

Ruth Avery is a Gilmer design close to what you've got. Kevin might be able to steer you in a good direction

Let's try that again
https://youtu.be/G0LEqpmx3tI

"to get the centers of effort exactly right"

the best/simplest method is "Davidson (Davidson Laboratory ) Center of Effort" =

1.7 x Jib and StaySail
1 x Main
0.5 x Mizzen

is surprisingly accurate and matches very well with what is observed in a Wind Tunnel

Attachment 88687

I remember the case of the project of an American schooner that they took to the Wind Tunnel of the Polytechnic of Milan ... and they would have saved money with this simple method

Attachment 88697

1.7 x
1 x "foresail"
0.5 x

"Davidson CE"

it's a surprisingly powerful little tool

Assuming that you have the sail plan of the original rig, calculate the CoE. Then using the same calculation methodology calculate the new rig and adjust it so that its CoE is in the same place.
This is the traditional method
https://www.cruisersforum.com/forums...p;d=1206347464
the final CoE is positioned IAW the ratios of areas, closer to the biggest sail.
A more rigorous method uses the fact that the centre of lift of a foil is at 1/4 cord from the leading edge. So the centre will be 1/3 of the height of the triangle and 1/4 back.

Hi,

I would suggest getting copies of Skeenes and Tom Cunliffe's hand reef and steer. While I love gaff rigged boats , have you thought about sailing qualities of a low spread out fore and aft rig vs the high bermudian with a cut away forefoot ?

Cheers,
Mark

Thanks for all the great replies. Will be digging through these. I have sailed a small handful of modest bermudian rigs, our boat included and quite a few gaffers and I'm curious what you think the performance difference would be. I have my reasons for wanting a low aspect rig, apart from pure love of them. I think they have quite an advantage off the wind, and offshore I don't plan to do many hard upwind legs, I like a low tension rig with oversized chainplates and serious redundancy of shrouds, stays, etc..

I am only judging these things from my sailing experience, my perception is that if I kept our short bermudian rig we would probably have an advantage of a few degrees further to windward, maybe 5-10 depending on how efficient or not the gaff rig is, but with the gaff rig w'ed have an advantage on a reach.

Id love to hear someone more learned than me with some real data comparing two similar in size bermudian and gaff rigs on a heavy displacement cruiser. I think with modern materials and the right sailmaker a real efficient gaff rig could be built that could be, not perhaps the equal of the bermudian in windward ability but not so far off as some people perceive them to be.

I’ve built a few gaffers, converted a few macaronis to gaff, and sailed em a bunch.
I love em ( Gaffers) for the reasons you mention.
I have no “real data”, I don’t deal in design numbers , don’t even know what all that stuff means,COE etc.
As you mention, we have modern stuff ,Dacron sails and hlyrds
Most “ regular” gaffers tack through 120. Go higher...slow down
I like to think of gaffers as simpler . Most folks want their boats easier.
Simple and easy are not the same thing.
I can go on and on....
bruce

Quote:

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Originally Posted by rkarakai21

Ohh, That looks like the ticket. Thank you. I can get that through Woodenboat?

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I have a spare copy of Gaff Rig by Leather, sent you a PM with my phone number if you're interested - I'm less than 30 minutes from you.

Jamie

My mentor, Paul Johnson, was(he still is but pretty old and out of it) talks about the comparison a bit in a 1970’s National Fisherman article that you may find enlightening. It can be found by just googling Paul Johnson national fisherman article . He influenced many many people to sail gaffers, maybe he can do it a few more times .

Read the article! Love it! I'm actually surprised that with modern lightweight materials and line there are not any modern cruising yachts coming off production lines with gaff rigs, it seems like a no brainer. It exists a little in Europe, a friend over in France just bought a modern designed vessel, shoal draft, fairly lightweight cruiser, fiberglass with twin rudders, twin keels, rigged as a gaff Ketch, and by all accounts it seems to handle quite well.

Same designer as this one.

https://www.yachtall.com/en/boat/nom...classic-374530

Quote:

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Originally Posted by rkarakai21

Same designer as this one.

https://www.yachtall.com/en/boat/nom...classic-374530

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I saw that boat on Monday, thought it was interesting!

sorry, unforgivable, forgot to mention this book

https://www.amazon.com/Ed-Burnett-Ya.../dp/1527230252

I also think Ed Burnett was a member of this forum