Thread: GIS X or Raid Special

Originally Posted by Clarkey

I think that with a relatively powerful rowing crew a lot of thought has to go in to what the rig is actually for on a raid boat. In many (most?) conditions the boat would probably make more speed to windward under oars, especially if the rig could be easily struck.

My preference would be a rig optimised for downwind blasting with very little emphasis on windward performance - the cartoon is getting close to this with the relatively small upwind sail area and the ability to fly a big asymmetric tacked to the stemhead. If it were my boat I would be tempted to reduce the mainsail area, have a little blade-like jib and a choice of kites.

I suppose it depends on the format of the raid - whether it is all sail/oar or whether they have sail only races.

The cartoon is for a course racing and distance racing under sail. No oars.

It is a boat for Mike.

or at least for him to laugh at!

I think a RAID boat would be quite similar to the Goat if not the Goat itself.

I don't agree with the pure downwind blasting, one of Joost's criticisms is that the boat couldn't keep up with the others upwind - though we have talked about some of the things that might resolve that elswhere - for example -

1. loose footing the main makes a big difference for getting power low down in the sail to fight chop.
2. Putting in an intermediate reef between the full sail and the first reef or rethinking the reef spacing completely.

The other thing on a boat performance basis is that if you want speed reaching or fetching ... you need a boat that will go well to windward too.

If a boat sails fast in smooth water at 45deg to the true wind, she is going to be rocketing at 55 deg ... if her hull will let her.

Same when there is a chop. A boat less optimised for upwind will be very doggy even at 60 or maybe 70deg. And then remember that when the chop gets up rowing starts to be very inefficient against the wind. But like you say it pushes the sail size down again!

The only way to go is to have a boat that can hold its own in good company upwind.

So for sail size. yes .. there is pressure for less sail, but it destroys the flexibility of the boat for other purposes. So a sensible normal sail plan and reefing that is correctly stepped looks the way to me.

I'm still not sure how I feel about a boat heaviliy optimised for RAIDing. Joost, Viola and their friends will get a lot of use out of the Goat for a big part of the year. I think that cannot be said about a more optimised RAID boat.

Mike's cartoon boat ... well ... it is not expensive or hard to build compared to other 20 footers. I would tend to make it a lot simpler in construction than the RAID41. Sort of an alternative concept to a "sportsboat" (won't be as fast, but will be way faster than people expect).

The biggest qualm I have about it is that it will take three to sail it. But Mike has enough sailing contacts that won't be a problem. If it got some notoriety as a performer and fun to sail then he might be knocking them back with sticks.

MIK

Originally Posted by Boatmik

Howdy,

I think it would work marvellously in 3D.

It is a bit like making apple pie. Some people add sugar to the apples, but you lose the contrast with the sweet shortcrust. In this case the boat has two other things going for it .. the short sailplan in relation to the length always looks very elegant. So I think she would hold onto it ok

Add lemon to the apple and boost the sugar in the shortcrust and it will knock your socks off!

MIK

Sorry MIK, to my old eyes its more a case of "oops, I added salt instead of sugar" My cooking skills ain't that great either.

Naa, slip in a couple more chines, a curved bow and slip in a sexy transom and then the gaff with the curved spar works better for mine. The spar may be simple to make but could make it harder to match the sail unless we send off a template of the spar to the sailmaker, because each one will be different with a different springback.

But that's just me being picky with a preference for functionality AND the visual. After all, the designers of Macquarie Innovation didn't give a stuff about the visual did they?! It just had to go fast And that's more what the Raiders are after isn't it?

Need to increase sail area for downwind, then maybe do what the original Raiders did......

And they didn't just raid for a couple of hours a day!!!

Actually the second pic is a bit cute. In the wind that has kicked up that much sea all the oars would be forced backwards by the sheer sailing speed!

They'd never catch the RAID41 to windward though.

MIK

Originally Posted by Boatmik

T
The other thing on a boat performance basis is that if you want speed reaching or fetching ... you need a boat that will go well to windward too.

I'm still not sure how I feel about a boat heaviliy optimised for RAIDing. Joost, Viola and their friends will get a lot of use out of the Goat for a big part of the year. I think that cannot be said about a more optimised RAID boat.

Mike's cartoon boat ... well ... it is not expensive or hard to build compared to other 20 footers. I would tend to make it a lot simpler in construction than the RAID41. Sort of an alternative concept to a "sportsboat" (won't be as fast, but will be way faster than people expect).

The biggest qualm I have about it is that it will take three to sail it. But Mike has enough sailing contacts that won't be a problem. If it got some notoriety as a performer and fun to sail then he might be knocking them back with sticks.

MIK

Mik,
The cartoon captures what I have had in mind or at least what I think I would like in a day boat.

The rig is a stunner and overcomes my concern that a long lean speed machine would need a yawl rig with short masts to make it manageable. Your idea would provide a multi plan set up that can easily be powered up......... wow a code 0 cool or depowered.

BTW I'm far from being scared off, thinking this might actually have legs.

Well that means I have to work out if that rig will actually work. Or tweak it so it does.

Do you want to build it as a 25 footer ... easy to change it now!!!

MIK

Thanks Mik,
Well if we're going for 25 why not 30 and 14 in the crew

Name: SSS414

http://www.semainedugolfe.asso.fr/in...bateau&tri=asc

Six will do you.

MIK

Originally Posted by Boatmik

I think a RAID boat would be quite similar to the Goat if not the Goat itself.

I fully agree! The GIS is works very well although a very different concept from most boats with it’s flat narrow bottom. She behaves beautifully and it would be a shame to loose the GIS’s qualities!

Originally Posted by Boatmik

I don't agree with the pure downwind blasting, one of Joost's criticisms is that the boat couldn't keep up with the others upwind - though we have talked about some of the things that might resolve that elswhere - for example -

Originally Posted by Boatmik

1. loose footing the main makes a big difference for getting power low down in the sail to fight chop.
2. Putting in an intermediate reef between the full sail and the first reef or rethinking the reef spacing completely.

The other thing on a boat performance basis is that if you want speed reaching or fetching ... you need a boat that will go well to windward too.

If a boat sails fast in smooth water at 45deg to the true wind, she is going to be rocketing at 55 deg ... if her hull will let her.

Same when there is a chop. A boat less optimised for upwind will be very doggy even at 60 or maybe 70deg. And then remember that when the chop gets up rowing starts to be very inefficient against the wind. But like you say it pushes the sail size down again!

The only way to go is to have a boat that can hold its own in good company upwind.

In these raids one tends to do what gets one fastest over the finish line: sailing if there is sufficient wind, rowing if not. It depends a lot on wind direction (and with stronger winds the swell): One leg we rowed the whole length of Loch Lochy (some 15 km's) downwind as this was fastest but we did sail a windward stretch in this leg as sailing did go faster than rowing on this course.

On a reach or downwind the GIS was the fastest boat on the water. Going to windward I often had the feeling that the wind was trying to push the boat over rather than to accelerate the boat (she just felt she could go much faster).

I am planning (fitting my current sail) to make a new beefed up boom square boom and fit it out as detailed in the Lug Rig Heaven post:

https://www.woodworkforums.com/showpost.php?p=804134&postcount=45.

The bottom of the sail will then probably become a bit fuller and more powerful as the sail will not get the change, as with the current very flexible boom, to flatten much due to the bending of the boom when pulling down the downhaul hard.

Originally Posted by Boatmik

So for sail size. yes .. there is pressure for less sail, but it destroys the flexibility of the boat for other purposes. So a sensible normal sail plan and reefing that is correctly stepped looks the way to me.

I fully agree. The sail plan should be sensible and not be drafted for raiding only (and even then it shouldn’t be much smaller anyway). It could however be made more versatile with the same sail area, by the following (part of which I will test as detailed above):
- beefed up boom
- loose footed sail
- more trimming possibilities by adding a kicker
- three reefs in smaller steps
- faster reefing system by adding cleats to the boom

If I the bigger boom is going to work out okay, I might consider having a new sail made to accommodate more reefs and a loose foot (very tempted to have Brian’s sail maker for his scow make this sail as the sail on his scow sets beautifully!).

Originally Posted by Boatmik

I'm still not sure how I feel about a boat heaviliy optimised for RAIDing. Joost, Viola and their friends will get a lot of use out of the Goat for a big part of the year. I think that cannot be said about a more optimised RAID boat.

I partially agree as I am not sure that I fully understand why we wouldn’t be able to get as much use out of a GIS optimized for raiding when considering the following:
1. The boat is very versatile as it is. I think that some tweaking will be sufficient to get the most out of the GIS’s sailing possibilities and to get her going a lot faster to windward. It should also be noted that we didn’t sail her often before the raid and we are still learning how to get her go faster.
2. As commented before, even under only one pair of oars (standard flat bladed ones), GISwerk did not loose that much time in comparison to the competition once we had figured the ideal set up after the first rowing race. I do feel that with a second pair of oars, we would have been able to come very close to the top 2 boats. I wouldn’t like any changes to the GIS’s layout and concept as they make the boat what it is: a fantastic performing boat! If a second thwart could easily be drawn into the GIS concept (even if this would mean a slightly larger GIS X) it might be worth thinking about as it shouldn’t harm the versatility of the boat.

Originally Posted by Clarkey

I think that with a relatively powerful rowing crew a lot of thought has to go in to what the rig is actually for on a raid boat. In many (most?) conditions the boat would probably make more speed to windward under oars, especially if the rig could be easily struck.

My preference would be a rig optimised for downwind blasting with very little emphasis on windward performance - the cartoon is getting close to this with the relatively small upwind sail area and the ability to fly a big asymmetric tacked to the stemhead. If it were my boat I would be tempted to reduce the mainsail area, have a little blade-like jib and a choice of kites.

I suppose it depends on the format of the raid - whether it is all sail/oar or whether they have sail only races.

In most Raids in Europe one can only set the "working sails" (square mainsails, normal jibs and mizzen sails): asymmetric spinnakers / genakers and such are usually not allowed.

Whilst it might be faster to go to windward under oars in a lot of circumstances, rowing with a cross-wind and/or cross-swell is tends make for a slower ride than under sail.

Joost, The new boom could be quite a light timber (spruce?) if you add a 10mm thick strip of hardwood along the bottom edge.

Originally Posted by Joost

I partially agree as I am not sure that I fully understand why we wouldn’t be able to get as much use out of a GIS optimized for raiding when considering the following:
1. The boat is very versatile as it is. I think that some tweaking will be sufficient to get the most out of the GIS’s sailing possibilities and to get her going a lot faster to windward. It should also be noted that we didn’t sail her often before the raid and we are still learning how to get her go faster.

Hi Joost,

That was me not explaining well. What I meant is if you create a RAID boat more specialised toward rowing, with restricted sail area it might end up being a very good RAIDing boat. The current Goat can be optimised more for the purpose with small changes and become a more than acceptable RAID boat.

Going to windward I often had the feeling that the wind was trying to push the boat over rather than to accelerate the boat (she just felt she could go much faster).

Yes, she is designed to go fastest upwind sailed relatively flat with two crew hiking out hard. And she is pretty good in that situation. I think maybe the toestraps will help even if you don't go into a full hike - every cm you can get those kilos out will make a big difference. I understand the difference with RAIDing too - so talking about a bit more.

The Goat is relatively narrow on the waterline which is where some of the this feeling comes from, and also a lot of where many of its advantages come from. So I think that doing some step by step changes to see what happens is the best approach. The loose foot set to about 10% draft should allow you to pull the sail on less hard and still get power upwind and it will give you a lot more power on a reach (you can ease it to 14% reaching) and back to dead flat running. Don't forget about trying the sail with no battens too - I found this made a big difference, as I have said.

2. As commented before, even under only one pair of oars (standard flat bladed ones), GISwerk did not loose that much time in comparison to the competition once we had figured the ideal set up after the first rowing race. I do feel that with a second pair of oars, we would have been able to come very close to the top 2 boats. I wouldn’t like any changes to the GIS’s layout and concept as they make the boat what it is: a fantastic performing boat! If a second thwart could easily be drawn into the GIS concept (even if this would mean a slightly larger GIS X) it might be worth thinking about as it shouldn’t harm the versatility of the boat.

I will start to look harder for the minimum distance between pairs of oars this week.

Brian's example of the little Tammie Norrie sounds like a good lead, any chance of tracking it down Brian?

MIK

In reading about the difficulties getting GISwerk sailing upwind I keep going back to Joost's statement about the sail. He said it was the flat cut sail from Duckworks.

If it is truly a flat cut sail (like the original junk sails) there's the problem! No amount of messing with different booms is going to make a flat cut sail go to windward the way a sail with proper draft can.

When I ordered my sail from Dabbler he sent me very specific instructions for measuring and reporting the flexibility of my yard and boom. Based on those tests he sewed in the right amount of draft, matched specifically to my spars.

Hello MAM,

We absolutely had no real problems sailing to windward, but we were a bit slower on this particular course than some other boats in the competition. On reaches and downwind the GIS was fastest.

It felt like that the boat could go faster on windward legs, but indeed that the sail was not allowing the boat to do that.

I am not sure about your statement that the boom has no effect on the draft. The draft cut into the sail (no broadseeming) now seems to disappear when tightening the down haul due to the flexible boom. If the boom is stiffer, the draft can not disappear as the boom cannot flex as much and this should result in (somewhat) more draft in the sail.

MIK is in a better position however than me to give a judgement on this…

But perhaps, althoug it sets nicely, it's cut is a bit too flat and a new fuller sail would be required to allow for more performance. If so, I wouldn't mind spending a bit of money getting it right and this very good discussion will provide the parameters for that (currently: same sail area, more draft, stiffer boom, loose footed sail, 3 reefing lines at smaller intervals, easier reefing by mounting cleats on the boom).

Best regards, Joost

OH JOOST .. the drawing of the boom I sent is for the RAID ... you will have to match the GIS length!!!! and did you realise the boom is symmetrical fore and aft .. so to set it on the other side of the mast just take it off the sail and change the front to the back.
__________________________________________________________________

Hey Joost, MAM, good little discussion .. a bit more info comes out each time.

Originally Posted by Joost

Hello MAM,

We absolutely had no real problems sailing to windward, but we were a bit slower on this particular course than some other boats in the competition. On reaches and downwind the GIS was fastest.

It felt like that the boat could go faster on windward legs, but indeed that the sail was not allowing the boat to do that.

Part might be that the other boats were bigger and heavier but the list of simple options in the posts above are worth checking first.

I am not sure about your statement that the boom has no effect on the draft. The draft cut into the sail (no broadseeming) now seems to disappear when tightening the down haul due to the flexible boom. If the boom is stiffer, the draft can not disappear as the boom cannot flex as much and this should result in (somewhat) more draft in the sail.

MIK is in a better position however than me to give a judgement on this…

Howdy, I think you are both misunderstanding each other a little. Joosts sail is not flat, but flattish. MAM is correct that a dead flat sail might have problems generating enough power.

The way I thought with the goat when designing the rig was that if it was big the boat will go well without many adjustments at all in light and moderate conditions allowing the sail to be simply laced. In stronger winds the sail could be reefed, unlike racing dinghies that use complex sail controls to shed the power.

With racing boats upwind in a chop - except in very light conditions it is best to get a lot more depth in the sail - both of you are saying that.

In a RAID if the wind doesn't give you near hull speed you will be rowing. And if the wind is stronger you do want to get rid of the depth of the sail near the top. This already happens with Joost's rig.

But where you do want the depth is down low to both give more power for punching through the waves without excessive heeling.

So we can introduce that by having a stiffer boom and a loose footed sail which can generate the list of depths I gave earlier. BTW with the reaching position of maximum depth I set it up so I can just let go of the outhaul and is shoots to that correct position and stops.

I have sailed a number of boats that would not go upwind well even in a real blow if the foot was too flat ... the Australian Sabre dinghy is one. makes a huge difference having about 100mm of depth in the foot of the sail.

But perhaps, althoug it sets nicely, it's cut is a bit too flat and a new fuller sail would be required to allow for more performance. If so, I wouldn't mind spending a bit of money getting it right and this very good discussion will provide the parameters for that (currently: same sail area, more draft, stiffer boom, loose footed sail, 3 reefing lines at smaller intervals, easier reefing by mounting cleats on the boom).

I disagree at this point ... get the new boom and get rid of the battens and see how it goes with more depth in the bottom. If it doesn't make enough of a difference then we look for more things. Maybe do some measurement of the yard bend and look at playing with that .. but I will be guessing the bottom is where the trouble is.

If the yard is bending so much that the top of the sail is flat with medium wind downhaul tension then we can look at the yard or the sail. If you lie the boat on its side Joost and set it up with medium wind tension on downhaul and sheet you could measure the depth of the sail and its position with a straight piece of wood at three heights. Sometimes the tops of sails look flatter than they actually are.

Maybe Soling will be into some two boat tuning!!! haha - you will look like Olympic sailors!!! Fix the slow boat so it is faster and then fix the new slow boat so it is faster!

Best regards, Joost

Hello MIK,

Thank you for your feedback.

Yes, I have realised that the boom for Raid41 is shorter and symmetrical. Still thinking about whether I am going to make a square boom per the Lug Rig Heaven discussion or the Raid41 boom. But anyhow this should not have any implications for setting the sail. Would the other dimensions of the Raid41 boom (besides the length) remain the same for the GIS?

Don't worry MIK, I will first extensively try to get the best ouf of my current sail before writing out a check for a new one!!! It will also teach me what is important to get most performance out of the sail and what could potentially be improved in a new sail. Just mentioning the factors that require attention.

I will make the outhaul easily adjustable via a pulley system and cleats and leave out the battens and see whether we can get some more depth and power in the bottom of the sail.

It will be fun trying all this, and even more so if Soling agrees to some boat testing!

Best regards, Joost