Doug, Paul,
I am used to the Spitfire and some F 18s, where a hook at the head of the jib hooks on to a ring on the forestay. The halyard is then untied and an adjustable downhaul controls the luff tension from the tramp. Depending on wind strength and mainsheet tension, the jib luff tension can be adjusted on the water.

Now downhaul the jib as far as you can without the mainsheet hooked on, then pull the mainsheet tight. Lets see how the jib react (rips ?). Different setup similar problem. One should not tension the jib to the point where the forestay goes slack.

Wouter

When the jib is adjustable from the tramp, there is no need to pull it too tight before hooking on the mainsheet. Hooking on to the forestay would seem to give better luff tension, and no ropes or cleates to give way.

Err... except for the downhaul rope and cleat, surely? I'm not familiar with the Spitfire setup, but it seems to me that either way, you've got a rope putting tension on the luff. Why would one way be better than the other? Either way, put too much tension on then crank on the main and you can damage your jib or the halyard.

But you're right, if the system is adjustable from the tramp , as the Blade's is, there's little reason to get it wrong.

Paul

Wouter:

I agree. On my 17 with reacher, I do as you said. Cleat the main tight for going to weather, then just snug reacher tight to take out wrinkles on the luff. Any more than that and you WILL snap the jib halyard. I lost a race due to jib dropping 2 feet when it broke. You are stuck till you come in to shore.

Doug

I can't believe that you don't ALL have a method for adjusting jib luff tension while sailing..... <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" />

Even the Swift Catamaran that I had in 1971 had an adjustable jib tension system. In 35 years I can only recall losing the jib once and that was on a Tornado when the internal limit wire on the jib broke where it had been kinked in storage.

BTW when I've got the Stealth jib fully tensioned (4:1 downhaul), the forestay IS slack. The jib halyard should be perfectly capable of holding up the mast.

When sheeting hard on a F16 you have about 600 kg load on the forestay. You'll pretty much need a 4 mm dyneema line to withstand such a loading. Alot of us are using much smaller (and lighter) diameter jib halyard lines often of lower quality material. Typical are 200-300kg 2mm and 3mm cheap imitation dyneema. These halyards break when loaded up to much.

But indeed, if a sailor is using a halyard that is thick and strong enough then it could hold the mast up with the steel wire forestay being there to do nothing.

Wouter

I inspected the broken mast, it was definitely not put into the mud

I wouldn't say the boards held up fine. . . apparently there were quite a few crab pots, I spent time nearly every race cycling the worst dinged boards out of service and using bondo to repair them. At the end of the event we laid all of them out together and there were quite a few repairs, although not as many as it seemed that I made. I did count at least one board that I had repaired 5 times

Kevin Rejda
Alter Cup Beach Captain 2006, 2007

I suppose, to be expected given the speed the boats were going, the fact that the skipper/crew couldn't see the 'pots as many were painted RED and significant white caps in the river and they all have barnacles on the mooring lines.....

Paul, the jib halyard and its cleat are under a lot more tension than the 3 to 1 system tensioning the luff on the Spitfire.
Wouter, usually you will see a curl in the luff of a jib, before it gets close to ripping. Very few people would race with that shape in their jib.

Kevin, great job with the boats last week. Your efforts are certainly respected and am sure you were not paid accordingly. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Dinged boards from hitting crab pots isn't a problem with the board. Any board will get dinged up in that situation.

Boards delaminating, breaking, flexing, etc. would have been a bigger problem (i.e. as relates to engineering and construction). The aspect ratio of those boards are new to the Blade, so there is always concern as to how they would hold up.

Dermot,

Neither would a Blade F16 sailor. That is not the point. The point is the crew tensioned the jibs on shore then hooked on their mainsheets and went sailing in 20 knots, cranking on the mainsheet. They probably forgot to look at the jib while sailing in these conditions and never adjusted the halyard tension. The same thing can happen with other jib tensioning setups. Afterall it all ends somewhere.

Wouter

Kevin,

How did the breakage on the mast look exactly ?

Looking to learn from this incident and if the cause was some fitting weakening the mast locally then maybe redesign it.

Wouter

The boards held up fine, one failed on practice day, it appeared to be a delam problem. BTW, daggerboards were not manufactured by Vectorworks.

If I recall correctly, the mast folded 18 inches or so below the upper diamond wire attachment point, no fittings or holes at that spot. I believe Matt has the pieces and plans to have them examined to see if there was a flaw in the extrusion. According to the competitors, they heard it go at the point of impact with the water. As I previously stated, there was definitely no mud on the masthead.

Seems to me that the new high aspect ratio boards on the F16 caused more problems then they solved. Besides increasing the draft (crab pots) the boat is now more difficult to de-power (control) in heavy wind. Perhaps the newly designed high aspect ratio boards should be left as an option. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

This is completely flase. The depower issues had nothing to do with the aspect ration of the boards. Where we sailed, especially this time of year is very full of crab pots. The local teams are pretty used to this and had little if any difficulty in negotiating around them. Given where most of the repairs were a shorter board would have hit just as many.

Also we can still make the orignal style boards for those who request it.

Thanks, couldn’t ask for more. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Obviously you are going to hit more crab pots with the increase in draft. As for de-powering in heavy air I expect the original low aspect ratio boards would be more desirable. Perhaps in light air (where crab pots are not present) the new high aspect boards would be advantageous enough to make it worth the trade off but that has yet to be proven….<img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Geez Buccaneer, you are so full of nonsense.

Now I know you like to come across strong to see if you can get a response but this is just over the line.

The difference in draft between the old and new boards is, hold on to something, 230 mm or less then 10 inches. I told you that the last time. The overall draft with the boards fully down is 1000 mm or just over 3 feet. That is waist deep water, anybody doing races in water that shallow is an idiot. You can't bury the bows then as that will break the hulls. If you capsize then there is a very high risk of breaking your mast when it is jammed between the bottom and the boat. I really don't think the Indian river was that shallow where the Alter Cup was held. It was more like 2 to 3 meter deep.

I think the issue was more that the boards snagged the bouy lines that were attached to the crab pods. These rough lines (barnicles) are then rubbed against the board or the leading edge of the board with force, making nice and deep grooves in the gelcoat somewhere near the keel line. Interestingly enough the old daggerboards will suffer the exact same fate.




Don't just "think" do the numbers on this and you'll find that the difference is too small to notice. These are not extremely narrow F18 boards that stick out 1000 mm to 1200mm below the keel line. These stick out 780 mm below the keel line compared to 550 mm of the old. This is a leverage difference of 4 %. The leverage here being the distance between the pressure point in the sail and the pressure point of the board.

I have yet to meet the guy that can tell, without using measurement equipment, when a length of pipe is 4 % off in length or weight. Why do you think a sailor can tell the 4 % difference in capsize moment between one set of daggerboards to another in every changing sailing conditions ?


Buccaneer, you are just looking for things to place the new daggerboard design in a bad light. There is nothing scientific or logical about your statements.

Now I'm not saying the old design is bad or anything, hell I'm happy with them myself. But that doesn't mean that either of us should just make up problems that really aren't there. God forbid some forum reader here might actually believe what you say and draw the wrong conclusions.

Wouter