Advice needed from a dinghy sailor

[dunkelly]

I have an old walker bay 8 for which i have made a rudder, dagger board and sailing gear . i used an old windsurfer mast and sail and made up my own gooseneck etc from delrin block . i have sailed it and all is ok from beam reach aft but she will not go to windward and definitely will not tack . i think that using a gf pole from a ws with its flex may be the problem . i was thinking it may be better if i rig shrouds and a forestay ( probably just rope and not sure how i would attach at the top ). anyone with experience have any advice ?

 

[Corribee Boy]

Is it because the centre of effort in the sail is too far forward?

 

[dunkelly]

Thats what i would have thought but the walker bay sail kit for the boat is very similar but with an aluminum pole and that seems to go to windward ok .

 

[Mavis]

Think of a Laser dinghy where it has an unstayed and very flexible (bendy) mast. The laser works extremely well to windward. It's as others have stated, and is all about the centre of effort between the hull, mast position and centreboard. Get that right and she will go to windward.

 

[lw395]

Think of a Laser dinghy where it has an unstayed and very flexible (bendy) mast. The laser works extremely well to windward. It's as others have stated, and is all about the centre of effort between the hull, mast position and centreboard. Get that right and she will go to windward.

The laser mast is not very bendy. The bottom section is a hefty old lump of aluminium.
The mast bends due to applying a serious amount of kicker tension.
A more flexible mast might be bending sideways too much.
As well as centres of effort etc, you need to consider fullness of the sail and what the head of the sail is doing. If the top bends off to leeward, the angle of attack of the top is all wrong and you're doomed.

 

[Mavis]

The laser mast is not very bendy. The bottom section is a hefty old lump of aluminium.
The mast bends due to applying a serious amount of kicker tension.
A more flexible mast might be bending sideways too much.
As well as centres of effort etc, you need to consider fullness of the sail and what the head of the sail is doing. If the top bends off to leeward, the angle of attack of the top is all wrong and you're doomed.

I think you are splitting hairs here, yes the bottom section is a tube where the walls are slightly thicker than the top section. You don't want to give the presumably inexperienced poster the idea that the the bottom section is solid aluminium. Yes, the laser mast bends backwards by adding a lot of kicker, but it will also bend off sideways at the top in the gusts. Yes, if the sail is not working properly it will not perform well. However, the point is that the CE needs to be in the right place and I think if he experiments with that then he will get the thing to sail on all points of the wind.

 

[bignick]

I have an old walker bay 8 for which i have made a rudder, dagger board and sailing gear . i used an old windsurfer mast and sail and made up my own gooseneck etc from delrin block . i have sailed it and all is ok from beam reach aft but she will not go to windward and definitely will not tack . i think that using a gf pole from a ws with its flex may be the problem . i was thinking it may be better if i rig shrouds and a forestay ( probably just rope and not sure how i would attach at the top ). anyone with experience have any advice ?

How much leeway are you making when you try to go to windward?

 

[keithb]

Hi Dunkelly
I think you are on the right track and a webbing snare on top of mast with non stretch rope shrouds the next step. However it's not the ideal shroud load point for a ws mast as you will know.
Windsurfers counteract mast tip flex to leeward by shifting c of e forwards when going upwind.
If this fix works you can then look for an epoxy ws mast and consider sewing webbing into sail sleeve at say 3/4 height for shrouds.
Hope it sorts!

 

[lw395]

I think you are splitting hairs here, yes the bottom section is a tube where the walls are slightly thicker than the top section. You don't want to give the presumably inexperienced poster the idea that the the bottom section is solid aluminium. Yes, the laser mast bends backwards by adding a lot of kicker, but it will also bend off sideways at the top in the gusts. Yes, if the sail is not working properly it will not perform well. However, the point is that the CE needs to be in the right place and I think if he experiments with that then he will get the thing to sail on all points of the wind.

Not unless the shape of the sail is roughly right from top to bottom.
Some photos would help.
It might just be that, like the laser, a lot of leach tension will help, both moving the head of the sail back, and giving it a good angle of attack to the wind.

 

[Neil_Y]

The top bending off to leeward is not a problem, it's used in yachts and dinghies for gust response/twist and as others have said the Laser works (sort of OK)

It's all about centre of effort assuming the sail looks half reasonable, sheeted in hard the boat should head up, I've also sailed a walker bay8 with their sailing rig and it isn't easy to get it to go upwind very well. It's short with lots of rocker so no directional stability. Bigger dagger board, further forewards or centre of sail further back. Lay the sail out and measure the centre of effort would be my first move. I've rigged windsurf sails (with standard boom) on a skateboard and fore and aft angle of mast makes a huge difference. The windsurf sail going upwind is raked back and you can't do that with a rigid mount for the mast, so rake the mast or move it further back should work.

 

[seumask]

Longer dagger board and raked mast. How is it in stronger winds, some dinghys like the minisail were difficult to tack in light air and really needed a sharp turn at speed to tack.
What sort of windsurf sail are you using as there are a wide variety and most with the COE further forward than the standard Walker bay rig IMHO. The walker bay rig looks like it has a longer boom than the average windsurfer rig.

 

[lw395]

The other thing is that moving your weight in the boat can have a big impact on where the centre of lateral resistance is. Moving forwards so that the bow is well planted in the water and the transom definitely isn't dragging might help. Side to side, generally keeping the boat level is a good starting point.
Some pictures really would help.
There are a lot of ways of stifling the windward performance.
Sail fullness
Boom angle

From what I can see of the WB 8, the dagger board slot is quite small and a long way back in the boat, while the mast is well forwards. Unless you are going to have a massively long boom and a very deep dagger board, the idea might be to use the bow as a big component of the lateral resistance by keeping your weight forwards.
Raking and/or bending the mast back may also be appropriate.
The American tradition of 'catboats' is in this kind of vein, often with a gaff rig which moves the top of the sail a long way aft from the mast foot. These boats don't tend to have deep centreboards.

 

[johnalison]

I used to have a little cockleshell dinghy moulded by Prout, with a small cat rig. It would do everthing I wanted except go about. Contrary to a post above, the solution was to withdraw the dagger board about halfway, when tacking was easy. Sometimes these things are just mysterious.

 

[lw395]

I used to have a little cockleshell dinghy moulded by Prout, with a small cat rig. It would do everthing I wanted except go about. Contrary to a post above, the solution was to withdraw the dagger board about halfway, when tacking was easy. Sometimes these things are just mysterious.

When you say 'it wouldn't go about' do you mean it tended to go into irons, or it wouldn't head up above close hauled?
Somehow a una rigged boat can be really well balanced, needing minimal rudder when close hauled, yet have a huge tendency to go into irons. And stay there. I think the centres of effort and lateral resistance both move according to whether the boat is moving or stopped. And some singlehanded dinghies are just out to get me!

 

[dunkelly]

Gosh gents a lot to think about with these things, big boat sailing seems much simpler or at least the way i approach it ,it is .!! grandkids over for the next week so will be playing with other things until they have gone . will be back out soon and will try a few of the things suggested take pics and report back so please be patient results etc to follow and thank you for all the advice thus far .

 

[johnalison]

When you say 'it wouldn't go about' do you mean it tended to go into irons, or it wouldn't head up above close hauled?
Somehow a una rigged boat can be really well balanced, needing minimal rudder when close hauled, yet have a huge tendency to go into irons. And stay there. I think the centres of effort and lateral resistance both move according to whether the boat is moving or stopped. And some singlehanded dinghies are just out to get me!

It would just get stuck in irons, however fast you were going. It just wouldn't pass through the eye of the wind, whether you were trying from close-hauled or on a reach. In all other respects it was balanced and easy to sail. I was fairly adept at sailing at the time and was racing a Firefly.

 

[lw395]

It would just get stuck in irons, however fast you were going. It just wouldn't pass through the eye of the wind, whether you were trying from close-hauled or on a reach. In all other respects it was balanced and easy to sail. I was fairly adept at sailing at the time and was racing a Firefly.

Reminds me of my early efforts with a borrowed RS600. When those things turn against you, they will stay in irons making fairly quick progress astern, sometimes climaxing with a bow-over-stern capsize.

 

[Neil_Y]

Reminds me of my early efforts with a borrowed RS600. When those things turn against you, they will stay in irons making fairly quick progress astern, sometimes climaxing with a bow-over-stern capsize.

The 600 can be a beast, I thought I could tack a dinghy but it proved me wrong on several attempts. I'm getting the hang of it now, in fast and flat even a little windward heel is helpful. But once they are stopped or reversing best to abandon ship.

 

[RJJ]

Centre of Effort is certainly worth looking at.

Do also remember that (1) not all boats like pointing (2) una-rigged boats sail with the boom over the quarter not the centreline. Maybe experiment with easing the sail and deliberately sailing 3-5 degrees more free. If you get some flow over what sounds like imperfect foils, then you may find you actually make better ground to windward.

Then you will have more speed in your pocket to help with tacking. On which subject, there is a tendency for una-rigged boats to send themselves into the wind and then be impossible to bear away. Keep your weight to windward (on the old side) until through the wind;
Make sure the main is well eased and the boat heeled to windward (new side) out of the tack.

Also make sure your foils are fair and clean. Disproportionate benefits

 

[Ruffles]

Are you using a traveller?

With a single simple sail if you sheet the boom inside the boat you'll soon come to a stop! Easy mistake to make if you've just stepped off a yot with a slot.