Stinger Blog

Main Trim

nospam@example.com (Bee) — Mon, 20 Feb 2012 11:33:06 -0500

Main trim on Stinger has probably the most important effect on speed. What I try to do in subsequent paragraphs is discuss some simple ideas to try and help us maximize speed and minimize confusion while we optimize main trim. Most of what I am going to say here is also in the North Sails trim guide. I really do recommend that you get one of these and read it as many times as I have read it.

The power of any sail is determined by its shape. Its shape is determined by the amount of twist it carries, its attack angle to the wind, and the position and depth of its draft. You have to think of a wing relative to all this but because our sails are soft the shape is much harder to optimize. I suppose everyone who has ever looked at a sail understands the effect of sail shape but, like me at times, may not know what to do to about it. Every sail control effects more then one aspect of sail trim at any given time, but the shape and affect we want is pretty clear in most cases.

Here is my view of what each sail control does

Primary functions:

The main sheet is the primary controller of the main's twist
The traveler sets the main's angle of attack to the wind.
The backstay simultaneously controls main and jib shape (fat or flat) and headstay sag.
The cunningham sets the main's draft position relative to the luff.
The vang sets the depth of the bottom third of the main.
The outhaul also sets the depth of the bottom third of the main.

It should be clear from these descriptions that use of these controls can produce some pretty dramatic effects on the shape of the main. Generally when the winds are light a fat main is desirable. When the winds are strong a skinny main is the order of the day. Clearly in all other cases, trim settings are somewhere between these two extremes. In the first case the vang, outhaul, cunningham, and backstay should be loose with the traveler up high with the main sheet set so the boom was on or slightly above center. In latter case the vang, outhaul, cunningham, backstay and main sheet are on hard but the traveler low. Clearly in the middle case, setting the main shape for optimum speed requires trim for a target shape somewhere between these two extremes. From my perspective, this is the hard part. Nevertheless, because a 105 is not starved for power in moderate winds we seem to do this pretty well.

As, an example, this shot shows the looseness of the sails in light air. Traveler is high and sheet is loose. Its worth noting that the jib sheet is also loose resulting in a highly twisted jib. Speed by sailing the boat fat is the issue here.

In contrast to light air the main here is very flat. This means the backstay and main sheet are on hard and the traveler is low

Secondary functions:

Each of the aforementioned controls has more then one effect on main shape. For now, let's not worry to much about that. Let's just be aware that each can have an effect on more then one aspect of sail shape.

Sail Trim in Various Conditions
OK, let's consider how to set these nasty things under various conditions. I'm going to take just a bit different tack then one reads in most of the sail trim guides.

As we race around the course we generally find ourselves in one of three states. We need to accelerate, we need to point, and we need to obtain optimum speed. To some degree each of these states requires slightly different main trim. A 105 is much faster slightly off then on the wind so to accelerate we need to foot off with the nose down and in that case we need lots of twist so the main must be a bit loose. When we need to point we need a narrow tack angle and not so much twist so the main has to be in and the traveler high. Unfortunately, what each of the terms loose, narrow, low and high mean is different depending on the wind conditions.

Let's see if we can set some rules of thumb for the kinds of wind conditions we usually find ourselves in.

Wind speed 0-10 knots

At the start we will always need to accelerate as we head toward the line. We want to hit the line with as much speed as possible. In these light air conditions, the traveler should be high (narrow attack angle) and the main a bit loose (lots of twist) . Here our objective is speed not point.

Once we get off the line we would like to optimize point so the main should come in a bit and we should be patient until we get a feel for what the boat is going to do. This action is really affected by sea state. In flat water less twist produces more point. In waves or chop, more twist produces more power and so maintains or increases speed. Generally a high traveler setting with the boom on or slightly over the center line is best in these conditions. With these settings the bottom baton should point directly at the backstay.

The general rule of thumb in 0-10 knots is to have the main full, no backstay, traveler up at or above the windward sheet edge, tight mainsheet, no vang, and wrinkles in the luff (light cunningham at most), and loose outhaul.

This is what the main should look like in 10 knots or less. Its a bit hard to see, but the luff has wrinkles. Its loose!. Note that the draft is roughly in the middle. Its certainly not all that forward so the cunningham must be off. The tack angle must be narrow and consequently the traveler must be high. I would bet that the outhaul is also loose.

Wind speed 10-15

Going for speed at the start, the traveler should be as high as possible without too much rudder drag. High here can be as much as 10 inches lower then the setting in 0-10 knots. It should still be above center but can be close to center line. We will not be starved for power but speed and acceleration will still be controlled by the main sheet.

As we get over the line, we will usually have enough speed to point as high as we can. Note that the settings remain the same conceptually, they are just not as high as they were when the wind was light. A General rule of thumb is to trim the sheet so that the top batten will stall about 50% of the time. Boom should be on centerline or maybe no more then 4 inches below.

The general rule of thumb in 10-15 knots is to have the sails a bit shallow, light to moderate backstay, boom as close to center as possible to perhaps 4 inches low, snug but not hard vang. no wrinkles in the luff and tight outhaul.

Wind speed 15-20+

We will have lots of power in these wind conditions. Coming up to speed is just a matter of main sheet adjustments. Here the traveler will be low at close to center or at 20 knots very likely below.

The general rule of thumb in 15-20 knots is to have a flat main, hard backstay, boom 6 inches below center. vang on hard. full on cunningham. and full outhaul as well.

A WORD OF CAUTION. WHEN THE VANG IS ON HARD IT NEEDS TO BE RELEASE AS WE ROUND THE WINDWARD MARK. If it is not released the result could be rig damage, sail damage, or both.

I would hope that someone would read this but I am uncomfortable telling someone this directly. I can usually visualize what I want in the sail, but I cannot do this while I'm at the helm.

GBCA FrostBite

nospam@example.com (Bee) — Sun, 19 Feb 2012 17:28:56 -0500

The weather god did not smile on this one. Light rain at the start, fairly cool temperatures all day, no sun, and light fog at the finish.

I forgot to turn on my iPhone Kattack tracker, Lakenmacher's iphone petered out before the race started., Uzi was a no show, and Zartler never plugged his in. Did not get to publish the race.

On the other hand Jim Powers managed to get 3 four leg races in in spite of the fact that the wind went through a 60 degree shift at one point. I think the good news on that was that we got to do 3 races. Its better to race, even on a parade, then it is to bob.

Daryl is really getting the main trim down. With a bit more time on the water he is going to be better then BC. Not only that but he weighs a lot less which helps keep weight off the stern.

Not much to tell about the first race. We went out got a great start and then chased Solaris around the course, pretty much in second all the way.

The second race saw us round the leeward mark in FIRST!!! ahead of both Solaris and Infinity. Then the stupid helmsman (oh crap that's me) did not turn down enough at the mark and Murat could not get the kite down fast enough to keep it completely out of the water. Still managed to crawl back into a spot where we could have taken Zippity out but just did not have enough course length to do it. Finished 1 second behind for 4th place.

In my mind the third race was the coolest. We managed to get to the point on the line where we could not make the pin so we tacked back on port, ducked all the starters, and then tacked into a wind shift that took us straight to the mark. With just a tiny bit more speed we probably would have at least got Zartler thinking about us. Nevertheless we settled into 2nd place and held on to beat Radiance by three or four boat lengths.

Nice to have a reliable crew that's willing to learn and do what it takes to up their game. Really a fun regatta.

Crew: Bee, Kevin, Charles, Murat, Daryl, Daniel

Man it was cold

nospam@example.com (Bee) — Mon, 13 Feb 2012 21:38:35 -0500

The warm weather of January lead us all to believe that February was going to be sprint time in Southern Texas. Unfortunately old man winter stepped in and blasted us with big breezes on Saturday and very nice 40 ish temperatures. I guess we all thought that leaving our cold weather gear at home was wise but it was not. Sunday was the worst with temps not even hitting 45 degrees. Nevertheless we all seemed to have a pretty good time. Jillina did a really great job as squirrel and jib furled. Was amazing to see that little thing furl that jib in record breaking time. Never thought something so tiny could be that strong.

It might be said that we did not do well, but with a guy on the main who had never really run a 105 main before we were always close. Did much better on Sunday and could easily have taken third.

Was happy

Crew: Kevin, Charles, Jillian, Murat, Chris, Daryl, and, of course, the fat man.

Da Diesel

nospam@example.com (Bee) — Sun, 05 Feb 2012 20:47:05 -0500

It appears that the diesel is fixed. While I was there, in my old age, I pretty much stood around as Uzi

Cleaned out the file tank, which from my perspective looked clean as a whistle
Replaced the Racor, which also looked clean as a whistle
Replaced the fuel filter, which see above
Replaced all the belts, which actually were the originals and needed to be replaced
Added a much needed quart of oil
Probably worked his hand to a pulp trying to bleed the system by hand. I bet he wishes he hadn't done that.
Had me add 5 gallons of marine grade diesel to the spotlessly clean tank.
Had me run the starter with the compression off for what seem an amazing long time until IT STARTED!

We let it idle for 40+ minutes while we had a bit to eat at the club and all seems well.

Now the questions:

What the hell happened to get that much air in the fuel system?
Will this happen again?
Do we actually need to keep the tank full?

Hmm.

Bee

Icicle 4

nospam@example.com (Bee) — Wed, 01 Feb 2012 21:45:43 -0500

Another fabulous January day. Great winds nice temps and great crew. Drank too much of the black elixir but other then that all was good. First leg was a bit of an upwind slog with relatively slow speeds and a terrible tack call by yours truly. Still managed to round E just behind Uzi and finish him off on the last leg. Fourth is better then nothing and after all this we are in second place. Will not be able to do Icicle 5 so have no idea where we will wind up be I think this year's Icicle was as good as it gets.

Only real negative was the fact that the engine would not run. Uzi towed us out and and back in so all was good.

Crew: Bee, Kevin, Charles, Murat, and Daniel

Who said this and when?

nospam@example.com (Bee) — Fri, 27 Jan 2012 22:26:01 -0500

All political ideology must be popular in tone and must keep its intellectual level to the capacity of the LEAST intelligent.

The future of any movement depends on the intolerance, even the fanaticism, with which its followers defend it as the only true one, and establish it as against other groups of a similar sort.

Political parties are given to compromise; we never compromise. Political parties recognize opponents; we declare their infallibility!

Icicle 3

nospam@example.com (Bee) — Sun, 22 Jan 2012 07:11:03 -0500

Another gorgeous day on the Bay. Light 5-10 SW winds gave us two chute legs for a nice third place spin around the course. We learned that in these winds we could fly the kite even with a TWA of 90 degrees.

Crew work was superb and a goodly time was had by all.

Crew: Bee, Kevin, Charles, Murat, Paul, Cody, and Daniel

Icicle 2

nospam@example.com (Bee) — Mon, 16 Jan 2012 16:44:40 -0500

Slight bit of a late start, but very nice light winds and a bottom as smooth as a baby's butt saw us blow past everybody but Gambler. Another one of those shoulda coulda taken 1st place races. On the other hand, second was OK since we did not have to wait around for the rest of the finishers. Uzi says that damn C&C kite is just a bit too much for him.

It certainly would have helped if Broaddus and I hadn't gotten so damn drunk. Will have to avoid that next time.

Crew: Bee, Kevin, Charles, and newbie Daniel Erklauer

Aw Shucks

nospam@example.com (Bee) — Wed, 11 Jan 2012 22:43:33 -0500

Lost another one today. Charley Dolezal, husband of my wife's favorite cousin bought the bullet today. Charles was famous for building hot rods and this was a talent he really perfected. 1931 Chev, 1932 Duece, and several hot rodded sedans were some of his best. Was fabulous to fire up one of the small block chevies he managed to cram into those small places. He will be missed.

Hard to reach this wonderful age. Too many old pharts disappear.

January 7th Icicle and January 8th Practice

nospam@example.com (Bee) — Mon, 09 Jan 2012 16:31:08 -0500

Icicle:

If we hadn't hoisted the red VMG backward we certainly would have taken 1st place. As it was we still managed 4th. Pretty darn good crew work overall. Can't really complain. Was a very nice finish -- J109, J105, J109, J105, J109, J105. JBoats can't get much more dominant then that.

Crew: Bee, Kevin, Charles, Cynthia, Cherlyn, John Dees.

Practice:

Four 105's participated. Our newbie Brian Uffleman drove Solaris and did a very respectable job.

Jay Lutz really put us through our paces. Started us in a staggered line with leeward boats about 2 boat lengths ahead of the leeward boat. After holding a line for speed we tacked over on port and repeated the exercise. After a bit we did the same thing downwind. He had us do some 360's just to make sure we were all in sync.

Bit biased but I think Stinger was the best boat out there. We had really good speed and did some really nice roll tacks. Not having Murat on the nose may for some interesting gybes but we got through those as well. Also managed to fly Ed's new class legal 89. Jury is still out on this puppy. Kevin says its kind of twitchy, but I could not see that anyone had any speed differences on us. Will have to learn how to fly it so its the preferred chute for next week's icicle.

Boat seemed to be a bit out of sync. Starboard tack was definitely easier to sail to then port. This was true with the kite as well. probably means the rig tune was off somewhat. Been a long time since that "feel" was there. Kevin will have to retune for the next icicle.

Crew:

Bee, Kevin, Daryl, Charles, Tony, and Lee

Boat Bottom

nospam@example.com (Bee) — Mon, 09 Jan 2012 16:29:02 -0500

Tom got 'er done. Finished late Friday evening and we managed to do the Icicle on Jan. 7 and the J105 Practice on Jan 8. Very smooth and very fast. Noticeable difference in boat speed. Lot's of bucks down the drain so to speak, but certainly worth the fun.

Boat Bottom

nospam@example.com (Bee) — Wed, 04 Jan 2012 15:46:23 -0500

On January 3rd pretty Stinger discovered that she was in the water without her bottom on. Suddenly she found herself sliding between powerful arms of a four legged travel lift. Thinking it could take advantage it moved her steadily toward a less then queenly hard spot. Not wanting to lie within the cruising hoard she brandished her cutlass to fight it off. Unfortunately in the process she discovered that her cutlass was no longer able to cut the shaft and her bearing was so loose she could barely move. Giving up the ghost, she submitted. She is now in surgery.

Although there is some potential that pretty Stinger will not be able to show her rear to anyone this weekend, she is quite optimistic that her bottom will be rewetted on Friday. If so, she plans to run it through the water during the coming Icicle. She is in great anticipation of the wonderful feelings that should arouse.

HYC revognaH

nospam@example.com (Bee) — Wed, 04 Jan 2012 15:41:54 -0500

What a nasty ride up to HYC. Wind out of the North 25+, big rollers, and lots and lots of spray. I think that was enough to keep us from getting our act together. Even managed to broach once. Not sure how we finished but probably close to the bottom in the spin fleet.

The ride home was a blast. Old CB and BB got a little happy off some rum and tonic. CB managed to keep the crew laughing all the way back.

A goodly time was had by all

Crew: Bee, Kevin, Charles, Murat, Chris, John, Trent, and Jillian

Updated

nospam@example.com (Bee) — Wed, 28 Dec 2011 22:36:01 -0500

Both www.3dbee.com (Stinger Site) and Fleet 17's websites have been updated. I tried to keep everything as simple as possible and hope there are no serious errors. If you find a link that does not work or something else out of kilter, let me know. The Fleet 17 Blog is about to appear, but be patient. I don't always do things as fast as I should.

Bee

Moved

nospam@example.com (Bee) — Thu, 22 Dec 2011 11:20:25 -0500

Stinger has moved. She is now in slip 23 on G dock at Lakewood Yacht Club. 2012 will see us race out of there.

I've posted a new calendar for 2012 and am about to upgrade the site considerably. Will probably post some new pictures as well. If you want to see a preview of the new site go to

http://www.j105.org/fleet17/