Dolphin striker wire tension

Technical discussion of ARC products
Mac M
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Boat Make/Model: SC17
Location: Lugoff, SC

Re: Dolphin striker wire tension

Post by Mac M »

I Drew I sent you a pm
Kevin Keller
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Boat Make/Model: SC-20, ARC22
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Re: Dolphin striker wire tension

Post by Kevin Keller »

Let's see some pictures J. Drew.
J Drew
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Re: Dolphin striker wire tension

Post by J Drew »

I won't be home for another 3 weeks, but I'll put them on then
SC15Av8or
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Re: Dolphin striker wire tension

Post by SC15Av8or »

Why are you hitting Dolphins with these??? :wink: :lol: :lol: I got nothing for you on this one.
Lifes 2 short for cheap GROG
SuperCat 15/19Av8or
J Drew
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Re: Dolphin striker wire tension

Post by J Drew »

Finally, some pictures
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Kevin Keller
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Re: Dolphin striker wire tension

Post by Kevin Keller »

Nice pics. I see you used better eyestraps than I did. Mine tend to cut the laces occasionally.
J Drew
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Re: Dolphin striker wire tension

Post by J Drew »

I was tempted to use the stamped eyestraps. The ones I used are almost $3 each, and there are a bunch of them.
Bill Roberts
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Location: Stuart, Florida

Re: Dolphin striker wire tension

Post by Bill Roberts »

The simplest way to adjust the height of the mast base above the beam is to make a spacer whose height is the same as the amount you want to raise the mast and the I D and O D of the spacer ring match the mast post/tube. Drop this spacer ring over the T fitting at the center of the cable and job finished. If you can't make this ring, Tom can do it for you.
REAR TRAVELLERS: The rear traveller cable system that comes with the boat works fine while sailing as long as the wheels and wheel bearings are lubricated and not worn out. A track type traveller system like a Harken main traveller system works better than the cable system under no load sitting on the beach.
JIB TRAVELLERS: The SC22 jib traveller system was developed after the RC27 jib traveller system with a straight track. The self tacking jib system was first developed on the 27 because my crew was having trouble jibeing the spinnaker and the overlapping jib at the same time. I put the first self tacking jib system on a 22 without spinnaker. This required a curved track near the track ends to encourage the jib car to run to the ends of the track
when a boat is sailing downwind without spinnaker. At that time the 22 had no spinnaker. The jib track improved tacking downwind without spinnaker because the jib could be trimmed further outboard, curved track ends, second trial, out without putting too much shape in the jib. The track is straight near center and plus or minus 1ft of center and this handles the self trimming and tacking situation sailing to windward. With spinnaker the jib car might move out ~ another 6 inches but a curved track is not necessary for the system to work properly WITH SPINNAKER. The slight curve in the track behaves as if it were straight. Again, the track on the SC22 was curved and the trays made to accomodate sailing downwind without spinnaker. This improved jib trim and boat speed while sailing downwind WITHOUT SPINNAKER.
Now, all the other beach cat builders think they have copied the self tacking jib system of the ARC products but they have not! They overlooked the importance of the mechanical advantage in the jib sheet system between the jib car and the jib clew. Without this 4:1 mechanical advantage pulley system in the jib sheet between the car and sail, the self tacker does not work. This is the magic secret! This pulley system in this place trims down on the jib leech with four times the force that is trimming the jib clew toward track center. Marstrom with the Tornado unknowingly tried the system without the 4:1 pulleys, an oversight; the spies that took pictures of the 22 in France without sails up did not see the 4:1 system. They found that the jib car came to track center when the jib sail itself was properly trimmed. The solution as they saw it, was to make the jib track curved for constant jib sheet tension, constant jib sail shape with car movement and then add another control line to set the off center position of the jib traveller car. This means the car is fixed and there is no self trimming with changes in wind velocity, puffs. Also the jib sheet tension is constant while tacking therefore this makes car friction and car friction makes the jib sail slow to come across and there is some back winding of the jib which slows the tack and boat down. With a straight track as the boat tacks, the jib sheet tension goes to zero and the car friction goes to zero and the jib floats across in perfect concert with the wind; better than a person could do it. Also with the curved track and jib car position control line, the crew has to come to boat center to reset the car position control line when the point of sail changes. With the straight track, this happens automatically in a coordinated fashion with jib shape/jib sheet tension. The sail developes more shape as the sheet is eased and the car moves out for reaching and sailing downwind. This all happens in a coordinated fashion with the wind.
The factory curved jib track shape that Tom developed with the trays works perfectly both with spinnakers and without spinnakers. The track is close enough to straight near the central working area so that the self trimming and self tacking principles work. The outer track ends are curved forward so the the car runs further out for proper jib trim for sailing downwind without spinnaker. With spinaker the jib car never runs to track ends for proper jib trim. If it did, the jib would be limp or luffing. The relative wind has swung very far forward with spinnaker and the jib must be trimmed in almost like sailing to windward. The mainsail is trimmed the same as going to windward.
OOOOH ME, I,m tired of writing.
Last edited by Bill Roberts on November 24th, 2013, 7:15 am, edited 1 time in total.
Mac M
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Joined: June 13th, 2012, 5:05 am
Boat Make/Model: SC17
Location: Lugoff, SC

Re: Dolphin striker wire tension

Post by Mac M »

Great information! Are the jibs cut differently for the straight and curved tracks?
Bill Roberts
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Joined: November 17th, 2003, 9:13 pm
Location: Stuart, Florida

Re: Dolphin striker wire tension

Post by Bill Roberts »

Same jib cut for straight and curved tracks. Self tacking jib tracks don't design jibs.

ALSO, in the last picture of the end cap, the hex nut appears too low. It should be up near the top of the end cap. This photo looks strange, like maybe the end cap is upside down?
Matt Haberman
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Re: Dolphin striker wire tension

Post by Matt Haberman »

Bill, I just noticed that too, and I agree that the end cap is rotated in the incorrect orientation.

Jon Drew, that end cap should be rotated so the hole (which is off center) is at the highest possible position.
Matt Haberman
Aquarius Sail Inc.
http://www.aquarius-sail.com
J Drew
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Joined: September 9th, 2013, 12:39 am
Boat Make/Model: SC 20
Location: n. florida

Re: Dolphin striker wire tension

Post by J Drew »

I can make that adjustment.
The end cap pictured is originally from the rear beam, I think the existing hole angle may be why it didn't want to rotate to the top. I'll have to check that out
Bill Roberts
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Joined: November 17th, 2003, 9:13 pm
Location: Stuart, Florida

Re: Dolphin striker wire tension

Post by Bill Roberts »

Front and rear beam caps for cable rigging are not interchangeable on SC20s. The hole size is different and the angle is different.
J Drew
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Joined: September 9th, 2013, 12:39 am
Boat Make/Model: SC 20
Location: n. florida

Re: Dolphin striker wire tension

Post by J Drew »

The hole size and angle are different. That's why I think the angle is what kept it from going to the top. I'll take it apart and examine.
The hole on the rear beam cap is smaller. I drilled it out. If I used the cap from the front beam, I would have to turn it down to fit the 4" beam.
J Drew
Professional
Posts: 104
Joined: September 9th, 2013, 12:39 am
Boat Make/Model: SC 20
Location: n. florida

Re: Dolphin striker wire tension

Post by J Drew »

After checking it out, the cap was assembled 180 degrees off, somehow? It didn't change it much, but, problem solved
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