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Boat Speed #262818
08/23/13 07:34 AM
08/23/13 07:34 AM
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Solomon's Island, MD
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samc99us Offline OP
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I've been thinking about this for a few days. We feel underpowered upwind, on the average (other boats are quicker to go double wire). We are also a little slow downwind in general. I'd like to focus on the upwind for right now:

1) New upwind sails and new long dagger boards aren't in the cards for this year. So we have the stock 08' performance main and jib and the Infusion short boards

2) In these conditions we've been running the jib on the second traveler post, sheet attachment in the top hole and a medium sheet. I ran the sheet a tiny bit looser last time to force my helm to foot. Thoughts?

3) Main trim: Upwind I pull the rotator on a bit so the spreader has about 1/2 to 1 inch of separation on the leech of the jib. To me this feels like I'm adding power. I know on the 20 we let the rotator flop. Thoughts? In these conditions we are loose on the cunnigham/downhaul and the main is generally fairly tight, I'd say about 8" of spread on the blocks but we are careful not to over sheet the main (using a leeward telltale at the very top back 1/3rd of the main).

4) Boards are fully down. We haven't really had a chance to test the adjustable trap setup yet, so wires are fixed at slightly below deck height.

5) We're a 305lb team carrying 17 lbs of lead, I know we'll be loosing a little lead before Nationals. But at this weight I feel we should be going twin wire before most other teams and that hasn't necessarily been the case.

And yep we've watched the Racine videos (Mischa) and others. Looking for additional opinions!

Thank You,
Sam Carter
Crew, Team Slippery When Wet


Scorpion F18
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Re: Boat Speed [Re: samc99us] #262826
08/23/13 09:44 AM
08/23/13 09:44 AM
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ksurfer2 Offline
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The infusion mast is really sensative to diamond wire tension. What have you got yours set at. Especially when I was sailing my infusion, I found that missing the diamond tension by just a little had a significant impact on performance.

Also, make sure you are not oversheeting your jib, keep the slot flowing!


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Re: Boat Speed [Re: ksurfer2] #262830
08/23/13 11:29 AM
08/23/13 11:29 AM
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Solomon's Island, MD
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samc99us Offline OP
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In these conditions we are at base, 37 on the loos gauge, 566.67 lbs according to the scale (found a nice picture on amazon here: http://www.amazon.com/Loos-Cableware-Tension-Diameter-Measurement/dp/B0000AXNQH).

We don't adjust diamond tension until we are maxing out the downhaul. It is my understanding these two effectively work together and have similar effects on the sail.

Our spreader rake is a full turn out from stock. By my measurement this is at 55mm, the recommended setting for lighter teams. I will double check before the mast goes up again. I can't say this was slower than at the stock 50mm setting in lighter breeze and we haven't tried it in heavier air.

Reading Tripps and Mike's guide they do suggest a little more mast rotation as the breeze builds than what I have been using, if the water is flat.


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Re: Boat Speed [Re: samc99us] #262862
08/25/13 01:49 AM
08/25/13 01:49 AM
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southern germany
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Re: Boat Speed [Re: samc99us] #262910
08/27/13 07:39 AM
08/27/13 07:39 AM
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Boston, Ma
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Jeff.Dusek Offline
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Sam,

Make sure you check your mast rake. I know at the Newport Regatta we were raked too far back and felt pretty crappy in the light to moderate breeze. We basically have a light and heavy setting. For the light setting we are between the two screws on the rudder retainer, and for heavy air we are slightly below the bottom one when measuring from the bridle with he trap line.

For the rotator, base is aiming at the shroud, and we rotate back pretty quickly as we start to pull on downhaul. Brooks generally keeps main trim until I am wiring consistently, and he has found he can crank the main pretty tight and we sail a fairly high mode most of the time.

For jib trim we usually have the inside of the car at the first post in from the end, and sheet in the top whole of the clew board.

Just some ideas!

Edit: Our base on diamonds is 37.5, spreader rake is 53-55mm

Last edited by Jeff.Dusek; 08/27/13 07:41 AM.

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Re: Boat Speed [Re: samc99us] #262965
08/28/13 03:31 PM
08/28/13 03:31 PM
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Solomon's Island, MD
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samc99us Offline OP
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Jeff,

Thanks for the ideas! We were at your recommended settings, and honestly had good speed for most of the day. We're at slightly below the top hole on the rudder retainer in light air. We didn't rake back in Hyannis and it showed.

I think Newport it was just a long day and we started loosing concentration. That is our biggest frustration honestly with the boat. It takes Jessica about 90% focus 100% of the time to keep the boat driving fast upwind. When I have helmed I found the same thing. It is most notable in light air, 3-5kts. Once I'm in the wire consistently the groove is wider. Do the newer sails help alleviate the strain on the helmsman?


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Re: Boat Speed [Re: samc99us] #262972
08/28/13 05:22 PM
08/28/13 05:22 PM
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SE MI / NE IN
rehmbo Offline
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Something that's impressed me this year is the influence of weight distribution. In lighter conditions (single trap and less), I'm up at the beam and my crew is either half way to the bridles or rotating out to trap. Goal is to get the lee transom up, but not quite clearing the water. Efficiency through the water seems to really be affected by this. I'm on a different boat, so ymmv.

C2 seems to like her nose in it as long as we're not getting major decels from the waves. Staying in the groove hasn't been too crazy tough, but you can't let your attention wander. When I'm up front, I steady the tiller extension via the side stay so I don't jerk it around too much.

Edit: Getting the nose down effectively rakes the mast further forward as well for a combined affect.

Finally, I'm not winning any regattas just yet, so take all this accordingly... smile

Last edited by rehmbo; 08/29/13 08:19 AM. Reason: added comment

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Re: Boat Speed [Re: samc99us] #262989
08/29/13 07:40 AM
08/29/13 07:40 AM
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Solomon's Island, MD
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samc99us Offline OP
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Jeff,

We too have noticed the weight sensitivity. Me transitioning from the N20 it's definitely more pronounced. We had the opportunity a few weeks back during training to play with this downwind while I was on the wire. I was moving for and aft and working on finding the sweet spot. Move too far back too quickly and you are really going slow.

Similarly, having the crew slide in and out while wired up in moderate conditions downwind with big puffs makes a HUGE difference in average speed. We still loose ground downwind but it's time on the water, and we're comparing ourselves to some of the best.


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Re: Boat Speed [Re: samc99us] #263006
08/29/13 10:28 AM
08/29/13 10:28 AM
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Boston, Ma
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Jeff.Dusek Offline
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Couple thoughts on crew weight.

On Saturday of Canadians (5-9 knts) I was trapping early and low upwind. Fore and aft position was at or a little ahead of the front beam. In the lulls I would pivot in to the hull, but in general I was trying to keep shoulders down and powered up. Brooks had the main mostly cleated during this, with some trim in the puffs/lulls. We were higher than most boats.

Downwind I have been spending much more time in the crew trap and keeping my weight around the board in flat water. Even in some chop I try not to be all the way back, but this requires a conversation with Brooks about how hard he can drive and if I am in a footstrap. Added benefit is the skipper trap is left open for Brooks if we need to go double wire.

As far as concentration in light air, Brooks takes a ton of credit here. He takes pride in his light air driving, especially down wind. Lots of respect from me for that!


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Re: Boat Speed [Re: samc99us] #263194
09/04/13 12:11 PM
09/04/13 12:11 PM
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Knokke-Heist - Belgium
Gilo Offline
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If you are in the top hole of with the jib, you will easily oversheet the jib and close the slot.
Also you want to sheet in quite hard on the main, if the leech closes pull some cunningham to open it again. If you just easy your mainsheet, you loose all the benefit of a puff.
Set your sails and have someone sail behind the boat. That's the best way to see if your leech is closed or if the slot is not open. Adjust and mark so you know your benchmark.

Also foot off enough to get speed. Apparent wind will change and you will be able to steer up and sail high with more speed.

If the water is flat I would have less rotation, flat water is a flatter sail as well.

The infusion is a great boat but you always have the feeling on the boat you are doing well (so I find it less responsive in that way). So I wouldn't trust too much on feel for this in light stuff.

On the downwind I would say easy the halyard of the spin a couple of inches and play a lot with your weight (for and aft; up and down) so you don't have to steer too much.

Just some ideas.

Gill

Last edited by Gilo; 09/04/13 12:16 PM.

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Re: Boat Speed [Re: samc99us] #263215
09/05/13 04:00 AM
09/05/13 04:00 AM
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In the really light stuff it can be a good idea to use the top hole on the jib, as long as you are trapping out too much (I change holes between races if needed).
In average breeze and above we usually have the jib car further out than the 2nd post though.
The trim guides are useful but only as a guide, I noticed when our sails got older we needed more diamond and cunningham..
In light air as crew I find it useful to sheet the main, that way the helm can focus on steering.

Gill: Are you coming to our F18 Nationals? Should be a good event: http://www.deltalloydodc.org/

Re: Boat Speed [Re: samc99us] #263237
09/05/13 02:39 PM
09/05/13 02:39 PM
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Knokke-Heist - Belgium
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Tony, most probably not as it is the F16 nationals as well in Hellecat...


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Re: Boat Speed [Re: samc99us] #263281
09/06/13 12:16 PM
09/06/13 12:16 PM
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Solomon's Island, MD
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samc99us Offline OP
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Interesting discussion and points. A few things:

1) Putting the jib in the top hole works exceptionally well for us in questionable single wire trap conditions and below. As others can attest we are quick in these conditions.

2) Cunnigham/leech tension argument is interesting. We will look at this on the beach next time we're rigged up and it's light

3) Driving down-yep, that's our #1 problem. College helmsman are used to pinching. When they stop trying to out-climb an A-cat they can be very fast uphill. Well, some, the naturally talented variety.



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Re: Boat Speed [Re: samc99us] #263476
09/10/13 11:36 AM
09/10/13 11:36 AM
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Tony,

There will be a Falcon F18 at Medemblik.

Gill


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Re: Boat Speed [Re: samc99us] #266563
10/30/13 07:08 AM
10/30/13 07:08 AM
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bacho Offline
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I have also made the move to an F18 from an i20.

I've only got 2 days sailing on my C2 so far. 0-5 on the windspeed.

I felt our downwind speed was OK, about what I was expecting.

We really struggled upwind, we lacked height and speed very badly. The boat seemed very sluggish in the puffs, and seemed very slow to accelerate.

My upwind sails are 2010 vintage, but I think they have been heavily used in that time. I have a new jib on order.

Our mast rake was at the top of the plastic clip above the lower pintle. Rig tension was 110lbs, diamonds were at 450lbs.

With a crew weight of 350, what should should I start with as a baseline on spreaders and diamonds?

I could be just expecting way too much coming off of an overpowered i20.


Re: Boat Speed [Re: samc99us] #266565
10/30/13 08:59 AM
10/30/13 08:59 AM
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Need the C2 experts to comment on your setup Bacho. A new jib may help but did a lot less than we thought at Nationals. Have a new main, but have yet to try it, supposedly they powered up the new sails and increased the range, I felt our 08' Performance Main had plenty of depth compared to the 13' sail but the newer sail can be trimmed flatter. If you're healing rather than accelerating in the puffs, this tends to be a worn out sail issue.

2nd hand information is the new C2 spreader range is 55-65mm, old range is 45-55mm. I would start at 50mm and a base diamond setting of 38 on the loos gauge.

The jib trim is also much more critical than the I20. The outer edge of the car should be just inboard of the 2nd post on the traveler, but again this varies based on traveler setup, breeze and sea state.

Also, need to sit way forward on the F18 in the light and especially lumpy. Helmsman at he forward beam, crew forward of that and even further forward (like bridle wires) if it gets lumpy. I think you can stay a little further aft on the C2, less stern to dig in but it's not a thin N20.

Finally, the i20 is faster in 0-5kts of breeze at the same crew weight. No way around it, more sail area, 2' more waterline and < 20lb platform weight difference makes for a faster boat. F18 Long boards have leveled the playing field in >5 kts of breeze, and when you need 420 lbs on the wire on the N20, 350lbs will keep the F18 nice and flat; plus the F18 hull shape is faster upwind in >12 kts of breeze, and we can carry the kite 10 degrees higher on a reach.


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Re: Boat Speed [Re: samc99us] #266570
10/30/13 03:27 PM
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Interesting observations on crew weight. If it's lumpy I try to stay right on the front beam, with helm and crew close together. If it is super flat I journey about halfway to the bridles, but not much further than that.


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Re: Boat Speed [Re: bacho] #266612
11/01/13 12:16 PM
11/01/13 12:16 PM
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Originally Posted by bacho
I have also made the move to an F18 from an i20.

I've only got 2 days sailing on my C2 so far. 0-5 on the windspeed.

I felt our downwind speed was OK, about what I was expecting.
you need to heat it up a bit more than the I-20 then work it down, can't just sail down like the I-20, unless it super super light then settle into low mode even if its slow. If in that low and slow mode and aren't even close to flying a hull pull your boats up about to the strap. Leave boards down to help facilitate flying a hull until the hull in popping up super aggressively that you can't control it with two crew members sitting on windward side."
We really struggled upwind, we lacked height and speed very badly. The boat seemed very sluggish in the puffs, and seemed very slow to accelerate.

My upwind sails are 2010 vintage, but I think they have been heavily used in that time. I have a new jib on order.
"new jib will help pointing a bit. we have 3 traveler car positions, just inside the inside post, centered overed inside post, and just outside the outside post (i dont know if weve actually used that last one). Generally we almost always sail just inside the inside post."
Our mast rake was at the top of the plastic clip above the lower pintle. Rig tension was 110lbs, diamonds were at 450lbs.
"mast rake is correct. Diamond tension 23-28 on loos gauge, tighter as it gets windier. Diamonds 37 base in super light air, 38 in anything over 5 especially if there is chop."
With a crew weight of 350, what should should I start with as a baseline on spreaders and diamonds?
"on 2010 sails they reccomend around 45mm on spreader rake, sam is right the new deeper sails use more spreader rake. If your light air and pointing is hurting try a bit more spreader rake. Personally I used 55 and liked it, tried 50, didn't like it, and went back to 55 and have been there since. We generally sail at around 390 but I sailed America's at 330 at the same. In reality the number is just a base number, you need to figure out the best setting for your sail and crew weight and it can vary largley."
I could be just expecting way too much coming off of an overpowered i20.



Skipper and crew just in front of front beam is generally max forwards on all F18s, crew can go a bit further but not much. Watch your bow knuckle and you want it just in the water, in super light air you may want to drive that in 4-5" but no more. If there is chop it should come out from time to time.

Re: Boat Speed [Re: Jeff.Dusek] #266748
11/06/13 05:52 PM
11/06/13 05:52 PM
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samc99us Offline OP
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Originally Posted by Jeff.Dusek
Interesting observations on crew weight. If it's lumpy I try to stay right on the front beam, with helm and crew close together. If it is super flat I journey about halfway to the bridles, but not much further than that.


Jeff, bacho,

We are still learning the boat but are usually quick in light air, trying to keep up with the 20's.; our Nationals results tell a different story but we were fighting a rudder issue the entire week.

Good video if you haven't seen it: http://www.youtube.com/watch?v=7uoRqshCqhI

Going much further forward than the front beam as a crew only works in very certain conditions, typically in light air with a slightly lumpy sea state, where you may have the rig set loose and you want some tension on it from the crews trap wire, plus a little weight separation may be advantageous, again depending on sea state.

When in doubt, sit further forward.

Last edited by samc99us; 11/06/13 05:56 PM.

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Re: Boat Speed [Re: samc99us] #266883
11/10/13 07:47 PM
11/10/13 07:47 PM
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wildtsail7 Offline
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Originally Posted by samc99us


When in doubt, sit further forward.


You keep telling yourself that Sam. That's a very old school thought of catamaran sailing, it's even the way I was taught. These new boats you can definitely sit too far forwards, a couple feet in front of the crossbeam is really max.

Last edited by wildtsail7; 11/10/13 09:50 PM.
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