Dutch gaff sail design

R.Ems

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Assuming we are using the same terminology..My peak bridle, I call it the span, is technically able to self-adjust as you suggest, but it found its natural resting place and hasn't moved for ages. Wire or chain is best, in your position I would leave it as chain for the moment.
Peak bridles are highly stressed, plus the consequences of them parting in strong weather would spoil your day! If you alter it, use wire, but someone probably designed it the way it is for good reasons... which may not be apparent until you have done some sailing in various conditions..
Some clever chap said just change one thing at a time and see the results first, before you change anything else.
The main is looking great after your tweaking!
 

Poignard

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westernman

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Ok, I'm getting a better shape to the sail now that I've tweaked the bridle at the peak (see pic). It needed to be offset slightly from a symmetrical triangle to get more tension to the peak. Noted that there should be a crease running from the peak to the tack, I can tune this.

Question: Would it be better to replace the peak bridle, which is currently made of chain, to a pulley on a rope system so it self-adjusts?

@westernman How should I deal with the bunching up at the clew visible in the second pic? Or perhaps this is just a knackered sail??
You can go up higher/tighter with the peak. The creases from the peak to the tack with the sail just hanging there should be well visible.
The bunching at the clew could be because the outhaul is a bit too tight, (but the outhaul is the same as for me - slacken it off and the boom will drop a little bit) or alternatively the hoops/bridle around the mast is a little too tight. But don't fiddle with this until you have got the peak up high enough.
 

westernman

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Assuming we are using the same terminology..My peak bridle, I call it the span, is technically able to self-adjust as you suggest, but it found its natural resting place and hasn't moved for ages. Wire or chain is best, in your position I would leave it as chain for the moment.
Peak bridles are highly stressed, plus the consequences of them parting in strong weather would spoil your day! If you alter it, use wire, but someone probably designed it the way it is for good reasons... which may not be apparent until you have done some sailing in various conditions..
Some clever chap said just change one thing at a time and see the results first, before you change anything else.
The main is looking great after your tweaking!
Mine is wire, and there is a kind of thing which attaches the pulleys to it which can slide along. It might need a bit of encouragement though.
I agree, the main does not look bad. I think a little more tweaking and it will look good.
 

LittleSister

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The bunching at the clew could be because the outhaul is a bit too tight, (but the outhaul is the same as for me - slacken it off and the boom will drop a little bit) or alternatively the hoops/bridle around the mast is a little too tight. But don't fiddle with this until you have got the peak up high enough.

Could the boom not be kept fully up while easing the outhaul by either a strop or hoop around the boom and attached to the outhaul adjacent to the clew, or having a diverter for the outhaul (ideally in a track?) on top of the boom?
 

dewshi

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Mine is wire, and there is a kind of thing which attaches the pulleys to it which can slide along. It might need a bit of encouragement though.

I will change it over to the same. I would imagine it settles slightly differently depending on reefing and boom position etc?

Currently my span is a chain attached to a shackle. Maybe the shackle is meant to run free across the chain, but it often gets jammed when I have tried it like that.
 

dewshi

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Thank you to everyone who has commented :)

Another question:

The mainsail is laced to the mast by lanyards with oak balls / parrel beads. Does this have any advantage over a single line laced through the points in the luff?

I'm thinking of switching over to the latter for simplicity.

IMG_4859.jpeg
 

R.Ems

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Thank you to everyone who has commented :)

Another question:

The mainsail is laced to the mast by lanyards with oak balls / parrel beads. Does this have any advantage over a single line laced through the points in the luff?

I'm thinking of switching over to the latter for simplicity.

View attachment 136970
Mine is laced, and I was thinking of changing to parrel beads! However the lacing works fine and I never got round to changing.. if it works, there is no point in changing it...
 

westernman

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Thank you to everyone who has commented :)

Another question:

The mainsail is laced to the mast by lanyards with oak balls / parrel beads. Does this have any advantage over a single line laced through the points in the luff?

I'm thinking of switching over to the latter for simplicity.

View attachment 136970
I think this is the best way.
(Mine is laced).
 

dewshi

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UPDATE:

Hello,

I've reconfigured the gaff span to a rope & pulley, so it self adjusts. See pic.

The knots are there to prevent the pulley accidentally slipping all the way to the end and getting jammed there when raising or lowering. This seems to work quite well. You can see from the second pic that the pulley settles closer to the throat than peak, rather than symmetrical. I think I can get enough lift to shape the sail.

Yeah yeah yeah, I know the crease isn't set correctly in this photo :)

I've also put in pulleys at the clew for tensioning the sail foot.

Another question: The boom sheet is controlled by a big old pulley block, 3:1 purchase, tied off to a cleat on the side. See pic. Is this enough pulling power?

Ideally I'd like a system with a built in cam-cleat, but I haven't one suitable in keeping with the overall classic style of the rigging. Any suggestions for an upgrade?

Also, there's no car or tracking system for the boom sheet. I guess this is normal ???

Thx

IMG_4889.jpegIMG_4887.jpegIMG_4885.jpegIMG_4882.jpeg
 

Laminar Flow

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A traditional Dutch boat is not necessarily a Tjalk. That is just one type of many and getting the sometimes subtle differences wrong will earn you ridicule and derision for your complete lack of insight by their Dutch owners and possibly cause an international incident. All these boats are descendants of commercial craft with very specific jobs, resulting in very specific designs.

A few observations in regards to the OP's rig:
Find out what type she is; she does not appear to have leeboards and there was a type designed like this for the herring fishery in the Zeuderzee, so that nets may be hauled up over the side without obstruction. Try to look them up for guidance on rigs.
Almost all Dutch gaffs are curved and there is some good aerodynamic reason for this. Mainsails tend to be lose footed as well, with a pronounced curve to their foot extending below the boom. The goose necks are set very low and very often separate from the mast, to allow for a mast lowering tabernackle and for booms to be used as a derrick. The Boom can rise towards the stern to avoid killing the crew; I've never seen a droopy one.
The gaff bridle on Dutch boats is made of wire. Most fishing types also had a raising bowsprit for light weather performance and from where they fly a jib called a Kluever.

I suspect you are barking up the wrong tree here, for advice on traditional Dutch craft, perhaps a Dutch site, dedicated to traditional Plattboden and ronde Bodens, might be more useful. Contrary to Mr. David Davis' comments, the Dutch seem to all speak excellent and idiomatically correct English and are very friendly and helpful as well. Of course, you could also get your boat cross-channel for a proper and culturally correct spa treatment and de-anglification program.
 

Laminar Flow

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Your boat is quite likely called a Staverse Jol. The various types are often named by the ports where they originated from, in this case, Stavoren. Google it, loads of info, lines and sail plans.
This type, unusually, has straight gaff. The mainsail is lose-footed and the boom angles up at about 15 degr. Some are fitted with a bowsprit. Instead of leeboards they have a a shallow keel.
 
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dewshi

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Your boat is quite likely called a Staverse Jol. The various types are often named by the ports where they originated from, in this case, Stavoren. Google it, loads of info, lines and sail plans.
This type, unusually, has straight gaff. The mainsail is lose-footed and the boom angles up at about 15 degr. Some are fitted with a bowsprit. Instead of leeboards they have a a shallow keel.

Thanks @Laminar Flow , this is really useful ! In fact I found my boat on a broker's site in Holland before it was imported by googling this style :)

By the way, when faced with Dutch ridicule & derision, I usually buy them a pilsner. It's avoided incident so far.
 

AntarcticPilot

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UPDATE:

Hello,

I've reconfigured the gaff span to a rope & pulley, so it self adjusts. See pic.

The knots are there to prevent the pulley accidentally slipping all the way to the end and getting jammed there when raising or lowering. This seems to work quite well. You can see from the second pic that the pulley settles closer to the throat than peak, rather than symmetrical. I think I can get enough lift to shape the sail.

Yeah yeah yeah, I know the crease isn't set correctly in this photo :)

I've also put in pulleys at the clew for tensioning the sail foot.

Another question: The boom sheet is controlled by a big old pulley block, 3:1 purchase, tied off to a cleat on the side. See pic. Is this enough pulling power?

Ideally I'd like a system with a built in cam-cleat, but I haven't one suitable in keeping with the overall classic style of the rigging. Any suggestions for an upgrade?

Also, there's no car or tracking system for the boom sheet. I guess this is normal ???

Thx

View attachment 137158View attachment 137159View attachment 137160View attachment 137163
I'm no expert on traditional Dutch rigs, but those figure of eight knots worry me. They will be severely weakening the strop, perhaps halving the strength of the rope, perhaps more. Others have noted that many similarly rigged vessels use wire rope for the strop, so clearly it is highly stressed.

I understand the rationale for the knots, but wonder if a Turks Head worked round the rope and perhaps held in place with a few stitches would be a better solution?
 

dewshi

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I understand the rationale for the knots, but wonder if a Turks Head worked round the rope and perhaps held in place with a few stitches would be a better solution?

Thx for the suggestion. I’ll try that.

I’m using 8mm braid with dyneema core, so it’s strong enough to replace wire by my calculations, but I hadn’t considered the impact of a knot.
 
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srm

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Regarding traditional/wood blocks, some years back I sailed a newly built boat to a traditional design and methods. I was surprised to find that the main sheet had a ratchet block to ease handling. Closer inspection showed that all the blocks were modern low friction ones. The builders had added traditional looking wood cheeks to the outsides for appearance sake.
 
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