wing mast -v- Bethwaite "wing mast"

No no Steve, I am sure I have seen that

move

many times on the regatta course <img src=

alt=

/>

Okay, there we have found the core of the disagreement.

I'm indeed only really familiar with the 29-er, 49-er, laser 3000, laser 4000, laser 5000 and RS800 design. To me these were skiffs. I have only seen (and touched) a 18 footer twice in my life and none of the others. I did not test the rig tension at those times

Apparently these boats are alot different then the real skiffs as that boat breaker you show in the pic it a true monster !

That baby will easily pull effectively 16:1 or close to a 1000 kg.

The pic didn't load the first time I read your post, my internet exploder, ... well ... had some issues. I understand now.

With respect to the sheet loads I guess once again the difference is between the semi skiffs like 49-er and the true skiffs.

I remember we had only one ratchet block on the 49-er with only a 70-90 degree wrap around the sheeve. Remarkably that felt alright with me. Also these spis would collaps as soon as you tried to head up to a high broad reach.

He Stephen the way you make it sound it appears that the skiffs are not sailboats at all, but rather body building apparatus ! <img src=

alt=

/> (joke)

I must really get a ride on a tornado sometime, apparently that is something else. I already feel that going from a Taipan 4.9 + spi to a modern F16 like the Blade is a big step up but it appears it gets better still. I never really believed that but maybe I need to do some fact checking in this case.

Wouter

So a

skiff

is not a boat configuration - it's a measure of the testosterone onboard?

They way the terminology is used over here is certainly different. If a boat measured in to the moth class rule, then yeah, it's a moth. The moth is a boat defined by class rules the same way an F18 is. Moth is a

dingy

(I guess?) and an F18 is a

catamaran

as is an I14 a

skiff

, etc.

I guess the problem is that folks in Aussy land consider the term

skiff

to not be a reference to the confiuration of the boat as we do in the US and in Wouter-land.

Get a ride on one could be a very expensive mistake <img src=

alt=

/>

Chris249 who use to frequent here was a die hard T4.9 sailor and had raced with spinnakers. I lined him up a ride on an old clapped out Reg White with spinnaker at the Sydney International Regatta SIRs...... And well, he was smiling from ear to ear when he hit the shore and could not stop talking about it. He could not believe the power of the big Ts.

I do miss my T <img src=

alt=

/>....... But feel I have made the right choice with the F18 Worlds in AUS. Will have to return to Ts after though.

Hello gents,

Wouter, on an 18 we don't have 20mins to haul the spinnaker up and play with moving shroud bases. Like TA said, the boat relies on pure grunt; the wing mast could be beneficial if you could figure out a system that worked efficiently. One day someone will, right now there isn’t the need for one.

As the poor bowman (yeah right I love it!!!) on one of these craft I can tell you that the spinnaker loads are out of this world. I have sailed on a F18 with TA in 30+ knots and there was no comparison between the sheeting loads.

The wing mast has been experimented with a long time ago but then was shelved after a fair few of them blew up downwind under spinnaker in 25 knots.

For reference the number 1 spinnaker on an 18ft skiff is approximately 750ft^2. That will vary from boat to boat as the sail sizes are unrestricted.

I have blown up a rig breaker before trying to get the rig tension on and whilst wave jumping in 20 knots on Sydney Harbour snapped 6 of the 9 or so strands which comprise 4mm wire. I think you could say the 18 rig has a fair bit on. Must be off now chaps, lovely chatting to you.

Cheerio
T_E

There is one thing I still don't understand though.

For all their grunt and huge sailareas, the VYC handicap ratings (statistics based) are still slower then a Hobie 16's.

Even the now real skiff 49-er is rated faster then the 12, 14 and 16 foot skiffs as well B14, cherub. As a matter of fact it is the second fastest rated MONOHULL boat after the 18 foot skiff. Pretty much 85 % of the cats is rated faster.

How is that explained. Is the rating system wrong ?

http://www.nsw.yachting.org.au/site/yachting/nsw/downloads/Yardsticks04_05.pdf

Wouter

Wow, 750ft^2 Spin on an 18' skiff (or whatever you want to call it) I've got a spin of that size on my 27' Stiletto. 36' Masthead rig and its huge... I've run a 400ft^2 on a 20' boat and sheeted it back to the rear beam. Where do you put the other 350ft^2?

Just curious as I know nothing about Skiffs. <img src=

alt=

/>

Clayton
S27, H16

Most of the skiffs listed never race in mixed fleets so data is not sent in (some numbers may be inaccurate, most are pretty good). The 18ft skiff is only slower by 2.5 points or so to the Tornado from that data (from memory) which would be an accurate reflection between the boats.

Pretty sure the foiling Moths are faster than a 49er too, will find out soon enough.

T_E

Hi Clayton,
The 18ft skiff rig is around 34' from memory and the bow sprit is around 12ft long. To be fair it is scary how much there is pulling you along. If you do a google image search you will be blown away at the sheer size of the sail area.
T_E

Wouter, I have sailed with 49ers and in NO WAY a Hobie 16 can be as fast as a 49er, something must be quite wrong with this yardstick.

For that matter, a 29'er is only rates slightly faster than a laser (mainsail only!)...I think it's mostly because a lot of the data reflects sailors who's skill level may not be sufficient to keep them upright around the course because a 29'er is most certainly faster.

I'll be sailing in a mixed fleet with I14s, 29ers, and possibly 49ers tomorrow--we'll see how it shakes out on the water.

At the end of July we will be racing a harbour marathon, followed by a regatta 2 weeks later on Sydney Harbour. Monos will include 29ers, 49ers, B14s, Cherubs, Moths, Foiling Moths, 12s, 14s, 16s, 18s.

Cats should include A Class, F16s, F18s, Tornadoes, Maccas Super Taipan...... So expect an ambush from the cats <img src=

alt=

/>

Brass Monkey Regatta 2005

18 Footer

The yardsticks for nearly all of the skiffs are slightly inaccurate there. The 29er is about the same speed as the 505 and Flying Dutchman (keep in mind Australia has the top 29er fleet globally),yardstick 95.

The Laser has a yardstick of 112, this is so low because it is sailed by such talented sailors who are extremely good at sailing the Laser. The average club sailor will not be able to race to this number on most occasions.

The 29er is a non professional class. In saying that when my friends went to San Fran for the 05 worlds they were training 6 days a week before hand (that is a hell of a lot of time on a boat). However, I beleive the tactical prowess would not be the same as older more experienced sailors who tend to not sail in the class very much. This means it could be possible for the rating to be even lower.

Oh the 12ft skiff rating is a load of bollox! Absolute rubbish I'm affraid. That boat can almost pace an 18 downwind! (runs deep because of the huge kite, almost as fast, in some conditions)

T_E

Bethwaite also talks about gust-onslaught response. He talks about wing masts being fastest in wind tunnel tests. The problem he had, was real world experience wasn't matching the theory. They discovered that in gusty conditions other rigs were faster. The wing masts are too rigid to bend automatically in the gusts. They developed rigs that automatically depower momentarily when a gust hits, giving the crew time to react to the gust, resulting in keeping the boat moving fast on its feet rather than heeling.
Seems like the windsurfer rigs are doing this also, but that the sails are cut to to bleed off power when you reach a certain amount of mast bend.

The closest I come to skiff sailing is an occasional sail on an I-14. So I don't have personal experience there, just seemed what appeared to me to be an important point in Bethwaite's book wasn't being brought up.

John
Miracle 20

Yes, but what does it do upwind ? The 18footer has 9 foot wide racks and am I correct that the 12' don't allow racks at all?

Wouter

Racks are allowed on the stern to help prevent nose diving downwind but they are inline with the max beam of the boat.

Upwind the boat isn't as quick obviously. I think someone said 9knots upwind tacking through 80 degrees, don't quote me on that. The boats have 4 rigs so they can have the appropriate craziness for each wind strength. The number 1 rig is 28ft high.

I think you have missed the whole point of the class though Wouter. You have to have big balls to sail these boats and the only reason they go upwind is so they can go off the planet downwind again.

Do some googling and you might understand where I am coming from. Tell me this, what two man 12ft boat does 24 knots downwind? I have seen the GPS tracks.

Cheers
T_E

12ft + a 14ft pole.

I don't think I lost the point at all.

A sailboat race is a race around a COURSE. As most will remember I go go against A-cat sailors who claim to be first at the A-mark only to be cheaten out of a victory by OVERALL faster spinnaker boats. In the same line of thought I go against skiffs that do 24 knots downwind only to crawl back up. Seems to me that those VYC ratings can be correct afterall. And that was of course the orginal point as I asked how it could be that those

around a course

handicaps were so slow for the skiffs.

I don't have an axe to grind here I'm still trying to learn why the skiffs are not using the Bethwaite square back rotating masts. The end criterium should be

around the course

performance. And as such the balancing of downwind and upwind performance is important. One poster mentioned that the rotating mast wouldn't carry the mast head spinnaker needed for the downwinds. But what if the true gains are to made upwind ? Would better upwind speed not be worth a smaller spi that the rotating mast can handle.

Looking at the speed difference of (roughly) 9 knots upwind (6.5 knot vmg) and 24 knots downwind (vmg 20 knots) it looks to me, as an engineer, that the upwind is by far the most important leg on these boats and that 5 % additional performance on this leg is worth any

over 15 % performance hit

on the downwind legs. ESPECIALLY when these boats are width limited. The latter point would also favour more efficient rigs and masts (bethwaite squarebacks) then the grunt rigs (round tubes and less earodynamic efficient) they feature now.

It seems to me that I'm actually full on topic here.

In sailboat racing it is all about making the best average around a course, not about maximizing one particular leg at the expense of everything else.

Afterall I can drop my boat of the nearest high rise building and achieve better speeds if it weren't for the problems getting back up again afterwards. <img src=

alt=

/>

Wouter

Do you think these skiff sailors are compensating for something ? <img src=

alt=

/>

Wouter

Yeah, their UPwind

performance

😛

Wouter, 12ft skiffs are a culture, it's obvious you will NEVER understand that. The 12ft skiff is not a professional class and to go out and blow however much money on a wing mast that could snap so easily is a bit much. The whole point of a 12 is the downwind ride. Get it in your head.

This season one of my mates built a skinny 12 and is in the process of trying to make a boat that is more efficient upwind to make the gains on the fleet here and try to hold them off down. It does not work yet because it is too unstable. I think you will find the guys here are a few steps ahead in finding out what works and what does not.

You’re a pretty obnoxious bugger and I think you should stop trying to analyse things you know pretty much nothing about and go back to wouterland.

When you drop your boat off the edge of that high rise building think about going along for the ride. You will then understand what a 12ft skiff ride is like.

Yeah Wouter, great call there champ. You’re a dead set idiot. Go play with yourself because no one else will.

T_E

oh no

you do realize that THE wouter isn't going to like that right?

You'll unleash a fury that will crash browsers.

Time for popcorn I think.........

How can this be a good idea?

5% gain on 9 kts upwind gives a speed of 9.45kts (so a .45 kts gain). Not much

15% loss on 24kts downwind gives 20.4 kts (so a 3.6kts loss).

Now unless the boat is having to sail a LOT higher to get this speed(which is not mentioned above), I'd suggest the

slower

upwind boat will still win around the course.

The numbers just don't make sense here.

Okay,

This is simple mechanics math guys.

If a boat is doing say 6.3 knots vmg upwind and 20 knots vmg downwind. how long will it spend racing on the upwind legs, and how long will it spend on the downwind legs of the SAME course ?

Indeed, it will spend 3 times as much time sailing upwind as downwind.

Say he is doing a race of 40 minutes; he is then spending 10 minutes sailing downwind and 30 minutes sailing upwind.

5 % gain on 30 minutes = 90 seconds
15 % loss on the 10 minutes = 90 seconds

So here a 5 % upwind gain cancels out a 15 % downwind loss. We all know that small reaches are included in sailing courses (impacting more on the downwind advantage then on the upwind one, again because of difference in spend time on each leg) and also upwind advantages are very important at the start and right after the start. So in this case I would favour the upwind advantages.

This is what I actually found while sailing the 49-er (and other likewise boats like RS800), which I'm told is not a real skiff. No matter how great the downwind legs it could and would get bagged by Hobie 16's (and other cats) by seriously lacking upwind speed. But then again I'm just an obnoxious nobody who knows diddly squad about sailing. <img src=

alt=

/> So maybe I could not sail that 49-er well if my life dependent on it. I am beating those H16's on my F16 though which has less sailarea and the same weight as 49-er; so I'm not a complete dud.

Wouter

Good point about spending longer on the upwind work.

Hi Wouter,

Theoretically you have brought up some good points. The only problem with the theoretical values of a 12ft skiff is they often are impractical for the class. The 12ft skiff is so small and susceptible to the environment around it that some ideas will actually mean that the boat is almost impossible to sail in normal conditions.

The 12ft skiff is prone to nose diving and needs the volume in the bow to help ride over the waves downwind. The volume of the hull also helps in this respect and provides a large planning base for the boat to sail on. One of the issues with trying to make a more efficient 12ft skiff is the boat is so small that some compromises must be made to make the boat sailable.

The new skinny 12ft skiff which looks somewhat like a skinny moth with a twin trapeze rig and huge asymmetric spinnaker attached. Theoretically the craft is much faster than the other 12ft skiffs upwind but on the water the boat still needs refinement. The narrow waterline has made it much harder to balance and any gains that have been made due to the changes have been cancelled out by capsizes or tea bagging (dropping the crew in to windward without capsizing). The boat will be sailing this season properly and we will have the chance to see how it goes.

The wing mast is on the agenda for many people down here but proves a challenge to the designers and sailors. The boats carry so much sail area to overcome hull drag and carry the desired crew weight they need the flexible upper mast tip to bleed open during the gust so that they can hold the power. So far the problem has been producing a wing rotating mast that would be able to let the rig de-power upwind but not be completely snapped off by the huge loads exerted by the spinnaker which is in the realms of 50m^2.

Mast compression is a concern in skiff masts and developing a rig which can cope with the loads induced is difficult. For all its short comings the round section does a sterling job and until a reliable wing mast can be produced will take precedence. I am sure you can appreciate the loads from the pictures that have been provided.

It is true that big gains could be made upwind in this regard and many of the skiffs are trying to make improvements in this area of their sailing. From what I have read you’re obviously a very intelligent person. In future I would ask that you show perhaps a little more respect for other classes. Nothing wrong with having an intellectual discussion but it would be appreciated if you dropped the attitude.

Sorry for the huge reply, so much to say.

T_E

About 12 I14s present and 8 29ers, most from the SF Bay Area. It was a real treat to see the I14 skiffs--wow, they are getting narrower every year. Very interesting rigs--fun to see how refined every detail was on some boats. I can only imagine how challenging the 12s are to sail. Hats off to the skiffees.

As far as speed around the course goes, really not much to say here as we didn't see them much after the first leg. I believe their

top end

speeds downwind would be insanely fast in breezier conditions than we had, though.

Mad. Are you sure the challenge isn't to pack as much $$$ per foot of boat? They would nearly be worse than the i14s to buy!

Tiger Mike