Thread: GIS handling characteristics

Originally Posted by callsign222

I've already got the sail at the sailmaker for grommets along the current reef points. The sailmaker also suggested another line between the foot and the first reef, but I said no, citing that Mik had the sail set up the way it would work best. What do you think, is a call in order to change the work and add another line?

If you want to take the GIS out camp cruising and/or solo sailing, I would add another line in between the foot and the first reef as suggested by your sail maker and in my post above. This would allow you more versatility and setting the correct amount of sail.

Originally Posted by callsign222

http://farm3.static.flickr.com/2672/...7b29c59fbe. jpg

This picture reminds me of a boomvang.

So basically, all these other threads about GIS spars, lug sails, etc. now makes sense. I've always viewed the downhaul as a downhaul, but it's actually both a boomvang and downhaul rolled into one! Conceptually, this now makes much more sense. My set-up provided absolutely no power in comparison.

Yes, the downhaul on a balanced lug rig does it all. Looking at the way I rigged it on my boat, please note the following:
- the tiny light blue line (mind you, it is very strong dyneema), ensures that the sail is hoisted at the right height every time: I hoist the sail until the blue line prevents me from hoisting the sail any further.
- the 3:1 purchase I have rigged seems to be sufficient. I have also tried 6:1 and although it allows you a more precise setting of the downhaul, it could be too powerfull for the standard GIS spars.

Very Interesting Thread !
I have not finished building yet, but did a light wind test sail with Joost. Two handed is seems a remarkable easy handled dinghy, I was surprized about the easy movements and almost yacht-like behaviour in small gusts ( just some extra healing, not much weather helm ).
But I will probably sail GIS mostly single-handed and perhaps extra ballast could be benificial?

I have made a boxed middle seat for extra flotation, but this could be used to contain water ballast too. The centerboard case devides this into two seperate left and right tanks. In case I want to use them for water-ballast I need to add on-top filling ports ( pour water in with bucket ) and draining plugs ( outboard, so these could drain while the boat is still afloat, before trailering ). Each side of these tanks contains about 65 liters of water, in case they are fully filled, so max extra weight is about 130kg.

I have thought about this, but did not make the final arrangements yet.
Would this make any sense? any recommendations from experienced single-handers?

Joost, you're awesome.

If I ever come to the NL again, I'll look you up. We can take your boat out, I will promptly capsize it, and then I will give you all sorts of advice on how to bail it out, because I've got a lot of experience with that now.

I just called the sailmaker and he was very much in favor of adding the additional line of reef points. So I will have three- the original two, and one half-way between the foot and the original first reef.

Another problem I encountered was that with the increased "scope" of the haylard with the reef in place, the yard had more play to it and wouldn't sit as tight against the mast as it does when it's hoisted to the top. Is this another downhaul issue?

Robert and Par

It's interesting to compare boats in the ways you've suggested. However, neither of your methods allow for mass. Allowing for mass I would think is relevant, given that the low mass of the GIS is a large factor in its performance?

Originally Posted by callsign222

i just called the sailmaker and he was very much in favor of adding the additional line of reef points. So i will have three- the original two, and one half-way between the foot and the original first reef.

Another problem i encountered was that with the increased "scope" of the haylard with the reef in place, the yard had more play to it and wouldn't sit as tight against the mast as it does when it's hoisted to the top. Is this another downhaul issue?

In this pic of my GIS in the driveway, it is reefed to the first reef point and does illustrate what you mention. Therefore the use of a low stretch halyard like dyneema is important, as is a powerful downhaul to keep the yard as close as possible to the mast.

I would think too that the attachment point of the halyard on the yard needs to move back when reefing as well, but this is something I'm going to have to find out in due course.

Attachment 139790

For the GIS with it's wooden spars, my gut feeling is that that more than 4:1 on the downhaul is unnecessary. Although I haven't yet run my controls back to the skipper's position, you can probably see that this is where I'm headed!

Attachment 139791

Originally Posted by callsign222

Another problem I encountered was that with the increased "scope" of the haylard with the reef in place, the yard had more play to it and wouldn't sit as tight against the mast as it does when it's hoisted to the top. Is this another downhaul issue?

Not downhaul, at least not downhaul when lots has been applied.

MIK specs a really neat arrangement, which I found keeps things well controlled and eliminates having a separate higher attachment point on the yard when reefing. Did you use MIk's system.


The clever bit is that the yard goes one side of the mast and the halyard the other so keeping things under control.

Brian

Yes, it is rigged per Mik's/sailing canoe system, with the halyard wrapping around the mast. Mine when rigged looked just like Bruce's in the picture above.

I think sliding the block back a bit on the spar might help, in the fogginess of yesterday, I seem to remember thinking that as I sailed back to the harbor.

For the record, I use this for my halyard and downhaul- low stretch dyneema. Just in case there was any doubt.

Excellent thread! This will be a great help as I get my GIS ready to sail!

That may still be put off a bit... I need to fix a previous omission in the build process that allows water into the boat faster than I can get it out! I know exactly what I forgot to do, so I know exactly what needs to be done.

I do find the information shared here and in other threads to be very helpful. Thanks

Originally Posted by callsign222

Joost, you're awesome.

If I ever come to the NL again, I'll look you up. We can take your boat out, I will promptly capsize it, and then I will give you all sorts of advice on how to bail it out, because I've got a lot of experience with that now.

You are most welcome when you are visiting the Netherlands (for sailing that is, not sure about the capsizing ).

Originally Posted by Watermaat

Very Interesting Thread !
I have not finished building yet, but did a light wind test sail with Joost. Two handed is seems a remarkable easy handled dinghy, I was surprized about the easy movements and almost yacht-like behaviour in small gusts ( just some extra healing, not much weather helm ).
But I will probably sail GIS mostly single-handed and perhaps extra ballast could be benificial?

I have made a boxed middle seat for extra flotation, but this could be used to contain water ballast too. The centerboard case devides this into two seperate left and right tanks. In case I want to use them for water-ballast I need to add on-top filling ports ( pour water in with bucket ) and draining plugs ( outboard, so these could drain while the boat is still afloat, before trailering ). Each side of these tanks contains about 65 liters of water, in case they are fully filled, so max extra weight is about 130kg.

I have thought about this, but did not make the final arrangements yet.
Would this make any sense? any recommendations from experienced single-handers?

I have not singlehanded her much (my girlfriend being very keen on sailing as well), but I would rather put in a reef than adding ballast and overcomplicating the boat.

The hull is very easily driven and in my experience a reef hardly makes a difference to the boat speed (because otherwise when not putting in the reef you would have to spill the wind anyway half the time).

Just my 2.

Best regards,

Joost

Howdy.

I haven't found much trouble with reefing BETH or the GIS using the reef points only. I don't guarantee that you can get away without reef points, but I was able to find I was. The important thing is to use the same tie down method as that standard corner tie downs.



The tie down has to be OUT to the end of the boom (or to the normal clew and tack eyes) but also you need to drop a loop around the boom as well to hold the sail down to the boom. Otherwise the sail will bag out badly in gusts and overbend the boom as well.

I don't know about the depowering problem. The only possiblity I can think of off the top of my head is if there was too much sail in front of the mast ... sail was too far forward. But it would have to be quite a long way for the sail to power up in gusts.

It might be OK and the angle of this shot would tend to exaggerate the overlap



I can see you are having trouble keeping the downhaul in the right place. We will get to that in a moment.

The correct place for the sail is approximately (from the setup page - http://www.storerboatplans.com/GIS/GISRigging.html)


If the 400mm distance gets too long then the sail will not depower as well. But I would expect quite a big distance more ... another 50 or 100mm won't change the depowering ... just give you too much lee helm.

That rope out the to tack is bad because it tends to overtwist the sail - this will lead to unstable downwind handling as the sail twists too much. Particularly when running or broad reaching. Come to think of it .. it may tend to overpower the front of the sail and twist off a depower the back part ... this might mean that in a gust ... instead of the back of the sail moving out that the front does it instead. I can't say that IS what happens but it is a bit more probable with tension in the rope out to the front of the boom.

So instead of the rope to hold the boom there are a couple of ways. Part of the problem might be that the downhaul was not tight enough. When the boat is overpowered you need outrageous tension in the downhaul. I think the others have covered that.

Now to stop it sliding forward ...

One way is instead of taking the downhaul over the top of the boom attach a block to the right position using the same loop and cow-hitch method as on the the other blocks. Or you could use the rope over the top of the boom but put a thumbcleat or a small deadeye to stop the boom from moving forward. It is best if the screws to hold the deadeye or thumbcleat is on the top of the boom. That way the area of the boom the holes are in is in compression.


http://farm5.static.flickr.com/4055/...a0712b4a6a.jpg

Screws do weaken a piece of timber loaded in tension but don't weaken one loaded in compression at all. Providing the screws stay in the holes.





Best wishes
MIK

Originally Posted by Watermaat

But I will probably sail GIS mostly single-handed and perhaps extra ballast could be benificial?

I have made a boxed middle seat for extra flotation, but this could be used to contain water ballast too. The centerboard case devides this into two seperate left and right tanks. In case I want to use them for water-ballast I need to add on-top filling ports ( pour water in with bucket ) and draining plugs ( outboard, so these could drain while the boat is still afloat, before trailering ). Each side of these tanks contains about 65 liters of water, in case they are fully filled, so max extra weight is about 130kg.

I have thought about this, but did not make the final arrangements yet.
Would this make any sense? any recommendations from experienced single-handers?

Howdy,

I don't know which would be better ... to put water ballast in the mid seat or more buoyancy (buoyancy at the sides is particularly beneficial).

you could potentially try both. Neither or both might be better than the original configuration for single handing.

Best wishes
Michael