Dutch gaff sail design

[dewshi]

The boom of my 28' Dutch Sailing Barge crosses the cockpit and definitely risks braining me & crew in a gybe.

I'm getting new sails made. Is it viable to have them cut so the boom doesn't lie horizontal, but gives some headroom? i.e the foot slopes upwards at an angle going up from the gooseneck to clew. I guess the reefing points would have to follow the same line. Maybe 10 degrees giving 30cm height at the end would do it. I understand I'd lose some sail area.

In the attached photo you can see the coach roof slopes upwards also, so the boom needs to clear it anyway. Obvs, I've got the original sails. But they are quite old and have lost their shape, so I'm not sure how the original design of the boat was intended. It was built in 1990 modelled a Lemsteraark gaffer. Pics of these on the internet seem to show them sailing with the boom at a jaunty angle. At the moment, when my main sail is fully unreefed and pulled reasonably tight at the peak, the boom still scrapes the wooden support block on the coach roof when at rest, so doesn't seem right.

I've got the chance to improve with new sails. Any advice or thoughts about this appreciated !!

 

[KevinV]

Not a sail maker, but that sail looks so far gone that it's pretty much useless as any kind of template - just specify what you want, the sail maker will make it so.
The mast has noticeable rake - it looks as if a shorter forestay would achieve what you want, but it may be meant to be that way?
Also worth bearing in mind that the boom will rise and be to port /starboard when you're sailing, making it less of an issue.
I'm just having my first foray into gaffers - it's a whole new world!

 

[R.Ems]

Welcome!
The sail looks knackered. I agree, don't use it as a template, being the wrong shape. It doesn't appear to be fully hoisted either.
The mast on such boats is usually at 90° to the water.
The gaff would not normally be straight but curved, best to google a few images of Dutch tjalks etc to see what I mean.
Have you got a bowsprit, a stays'l and a jib?
Where was she built, have you any old pics of her rigged under sail?
You will need leeboards to sail, are there any fittings for them?
Was she built as a sailing vessel, or is she a home-build in the Dutch style but not intended for sailing?

A very interesting project anyway. Looks like the Regent's Canal?

 

[sarabande]

I think the Dutch masts always slope aft a lot.

Probably worth checking that the gaff peak can be lifted higher to raise the boom, or even, if you are going for a new sail, that you might consider a loose footed main ?


Is that Richard Branson's pad in the background ?

 

[LittleSister]

Agree you need a new sail, and not one based on the current one. The sailmaker should come and measure the rig, or at least tell you what measurements s/he requires to design the sail.

Try to find a sailmaker who regularly makes sails for gaff rigs. They will all do so sometimes, but most will, I imagine, do so only relatively rarely among their Bermudan sails work. You can ask on this forum for recommendations, indicating where you are located.

Rather than have the boom canted upwards too much, if it were me I would raise the gooseneck (i.e. fit the boom slightly higher on the mast), and do this before measuring up and getting a new sail cut.

 

[R.Ems]

Good point about raising the gooseneck.

 

[Tranona]

As already suggested, talk to a sailmaker with experience of gaff sails. Here jameslawrencesailmakers.com is a good place to start. Another sailmaker well known for working boat sails here skbsails.co.uk

 

[westernman]

The boom of my 28' Dutch Sailing Barge crosses the cockpit and definitely risks braining me & crew in a gybe.

I'm getting new sails made. Is it viable to have them cut so the boom doesn't lie horizontal, but gives some headroom? i.e the foot slopes upwards at an angle going up from the gooseneck to clew. I guess the reefing points would have to follow the same line. Maybe 10 degrees giving 30cm height at the end would do it. I understand I'd lose some sail area.

In the attached photo you can see the coach roof slopes upwards also, so the boom needs to clear it anyway. Obvs, I've got the original sails. But they are quite old and have lost their shape, so I'm not sure how the original design of the boat was intInended. It was built in 1990 modelled a Lemsteraark gaffer. Pics of these on the internet seem to show them sailing with the boom at a jaunty angle. At the moment, when my main sail is fully unreefed and pulled reasonably tight at the peak, the boom still scrapes the wooden support block on the coach roof when at rest, so doesn't seem right.

I've got the chance to improve with new sails. Any advice or thoughts about this appreciated !!

In the photo, the peak of the gaff is not anything like high enough. You should haul the gaff up until you get creases running from the peak to the tack. These will then disappear as soon as wind fills the sail.

 

[dewshi]

Thx.

The mast has noticeable rake - it looks as if a shorter forestay would achieve what you want, but it may be meant to be that way?
Also worth bearing in mind that the boom will rise and be to port /starboard when you're sailing, making it less of an issue.

Yes I think the mast is as designed, at a rake. It lifts and lowers for inland waterways, on a cantilever system. The base is in a metal cage in the hull, and the forestay is adjustable, set pretty much as tight as it will go. So this is the angle of the mast. Unless it has bent with time ??? I don't think so though.

Sure, good point that it will rise as the sails fill with wind.

 

[dewshi]

Welcome!
The sail looks knackered. I agree, don't use it as a template, being the wrong shape. It doesn't appear to be fully hoisted either.
The mast on such boats is usually at 90° to the water.
The gaff would not normally be straight but curved, best to google a few images of Dutch tjalks etc to see what I mean.
Have you got a bowsprit, a stays'l and a jib?
Where was she built, have you any old pics of her rigged under sail?
You will need leeboards to sail, are there any fittings for them?
Was she built as a sailing vessel, or is she a home-build in the Dutch style but not intended for sailing?

A very interesting project anyway. Looks like the Regent's Canal?

I have seen pics of curved gaffs, this one is straight. No bowsprit or stays'l. I've got a Genoa.

I believe she was built in Zaandam. Sadly don't have pics of her before I got her.

No leeboard. Lifting Keel is 2 m. The draft when it's up is 0.8m.

I don't know what a home build not intended for sailing means ?? She is definitely a sailing vessel )

 

[dewshi]

I think the Dutch masts always slope aft a lot.

Probably worth checking that the gaff peak can be lifted higher to raise the boom, or even, if you are going for a new sail, that you might consider a loose footed main ?


Is that Richard Branson's pad in the background ?

Thanks for this.

The photo I posted shows the main sail with 2 reef it. It was the best one I had to show the boom angle. I have tried it on full sail. I've cranked up the gaff peak hard: the boom still sits low though once the boom topping is dropped.

Several people on here have commented that the old sails are too far gone to be a reliable template, and that totally makes sense.

HAHAHA I thought I spotted Branson in the window. The photo is from April when the boat was up in Islington, actually opposite Boris's old house. There were some very posh people that came out of one of the houses to admire the boat when I was moored in Primrose Hill. They invited me to tea. So, I may get lucky with Branson next time... :--)))

 

[dewshi]

Agree you need a new sail, and not one based on the current one. The sailmaker should come and measure the rig, or at least tell you what measurements s/he requires to design the sail.

Try to find a sailmaker who regularly makes sails for gaff rigs. They will all do so sometimes, but most will, I imagine, do so only relatively rarely among their Bermudan sails work. You can ask on this forum for recommendations, indicating where you are located.

Rather than have the boom canted upwards too much, if it were me I would raise the gooseneck (i.e. fit the boom slightly higher on the mast), and do this before measuring up and getting a new sail cut.

Thanks for the tip !

The gooseneck can't go any higher, as it has to sit below where the mast folds down. Attached is a pic with it down... not a lot of space there

 

[dewshi]

In the photo, the peak of the gaff is not anything like high enough. You should haul the gaff up until you get creases running from the peak to the tack. These will then disappear as soon as wind fills the sail.

As mentioned in another reply, the photo shows the mainsail when it was reefed. That pic happens to show the boom angle best as it's square on. Sure, I've had the sail fully up. Here's another pic... though it's hard to judge the angles and lines of the boat from the perspective.

Thanks, I've heard that you need to adjust the gaff peak tension with a crease. Also differently for upwind & downwind.

 

[LittleSister]

The boom height doesn't look so bad in the later picture. I know you said that that's being held up by the topping lift, but you could have a sail cut, no problem, to keep it at least that high when the topping lift is off.

Given the constraints and overall size/design, I think you will just have to learn to duck, and to be very careful when running (and rig a boom preventer).

 

[westernman]

This is what a gaff main should look like when the peek is correctly set up.
The topsail sheet is over-sheeted though.

 

[KevinV]

BTW, if (like me) you're new to gaffers, then Hand, Reef and Steer is a very useful book to have - lots of info, chaptered so you can skip the bits that don't float your boat

Hand, Reef and Steer 2nd edition: Traditional Sailing Skills for Classic Boats: Amazon.co.uk: Tom Cunliffe: 9781472925220: Books

 

[westernman]

BTW, if (like me) you're new to gaffers, then Hand, Reef and Steer is a very useful book to have - lots of info, chaptered so you can skip the bits that don't float your boat

Hand, Reef and Steer 2nd edition: Traditional Sailing Skills for Classic Boats: Amazon.co.uk: Tom Cunliffe: 9781472925220: Books

I can highly recommend that book. It was very useful for me.
Also Tom Cunliffe at the time had a (smaller) sister ship to mine which is the photo above.

 

[DownWest]

I would still look at ways of raising the gooseneck , even if it looks difficult at the moment.
Obviously the sailmaker can cut the sail to any height over the cockpit. The result would just be a question of looks, along with some efficiency.
Just curious as drop keels were not usually a feature of Dutch designs, hence the lee board questions. Any designer we would know?

 

[dewshi]

I would still look at ways of raising the gooseneck , even if it looks difficult at the moment.
Obviously the sailmaker can cut the sail to any height over the cockpit. The result would just be a question of looks, along with some efficiency.
Just curious as drop keels were not usually a feature of Dutch designs, hence the lee board questions. Any designer we would know?

Unfortunately raising the gooseneck is not going to happen without completely scrapping the mast. I'll take a pic later, so it'll be clearer why... Meanwhile, perhaps it's apparent from the attached photo with the dog what the mast looks like when folded down. The gooseneck sits low at the base, literally inches below the mast.

I too would like to find out who the designer is, as it seems to be a one-off

 

[dewshi]

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??