Why not?

[Heath68]

Hi Guys,
OK.. now admittedly I'm a newbie to many sailing things but here's a question.. Why are "self tacking" gib tracks shaped like they are?

All I've ever seen are an arch shaped thing in front of the mast. Now I'm a cat person (apologies mono enthusiasts) but why aren't the "runners" (is that the correct term?) shaped in a U shape rather than a simple curve?

I'll try and upload a drawing or two but if the runner was shaped in a U, the sheet could be pulled back as more of the gybe was let out, allowing the gybe to go wider.

Answers on a postcard.. or if you prefer.. down below.


OK I can't upload a pictures because this stupid editor thing asks for a URL!??!?!?

[Heath68]

That was my second attempt at uploading pics.. PLEASE make this easier!!!

[Sailmonkey]

Well, in order to maintain a sheet tension and angle the curve shape is utilized. This allow the the jib sheet tension to remain constant from one tack to another while the sail moves side to side without intervention. If you change the shape of the track it will no longer be self tending.

[Heath68]

Originally Posted by Sailmonkey

Well, in order to maintain a sheet tension and angle the curve shape is utilized. This allow the the jib sheet tension to remain constant from one tack to another while the sail moves side to side without intervention. If you change the shape of the track it will no longer be self tending.

I understand that.. so on a constant line length, it would self tack.. but then with letting the furler out.. and utilising the bottom of the U shaped track with more line, would this not allow for a greater use of the foresail?

I wish I knew how to upload a pic .. grrrr

[Cheechako]

The length of sheet is longer at the outer ends of the track on a straight track. So tacking should not be a problem for a straight track ... right? the sheet will be loose as it passes across center. and... straight track and support is cheaper to make!

[Sailmonkey]

Originally Posted by Cheechako

The length of sheet is longer at the outer ends of the track on a straight track. So tacking should not be a problem for a straight track ... right? the sheet will be loose as it passes across center. and... straight track and support is cheaper to make!

Ture, but curves are sexy. The curved track on something like a beach cat is utilized so you can maintain sail shape through the whole tack.

[boatman61]

Download the picture to your computer then when you make a post click on the paperclip image by the smiley and it opens a window.. chose your picture then click send.. as soon as it appears in the box window click on upload.. wait a minute then close window and finish post as normal.

[Paul Elliott]

To upload a picture, click on the "Go Advanced" button at the bottom of the "Quick Reply" window. Scroll down and you will see the "Attach Files" box. Click on "Manage Attachments" and you will see "Upload File From Your Computer". Select the picture file, and it will show up at the bottom of your post.

[Yes, as boatman61 says, you can also click on the paperclip icon. This only appears when you are in the Advanced editing mode.]

As for the self-tacking jib, the track shape is probably designed to maintain the correct jibsheet lead angle (as best as can be done given the variables).

[Sailmonkey]

Originally Posted by Heath68

I understand that.. so on a constant line length, it would self tack.. but then with letting the furler out.. and utilising the bottom of the U shaped track with more line, would this not allow for a greater use of the foresail?

I wish I knew how to upload a pic .. grrrr

Are you trying to say you want something that can self tack with a furled headsail, but then be used for sheeting an overlapping genoa?

[Heath68]

OK the first picture (I hope) shows as is now... the second pic (I think) seems to allow a tension kept in the furler and the self tacking jib to be used.. but allowing more of the jib out and utilising the U shape allows more sail to be exposed without the use of a new sail.. ??


ok I can see I've drawn the lines wrong but do you get what I mean?

[Heath68]

I think I meant this....

[Sailmonkey]

I’ve got absolutely no idea what you’re trying to get across.

[Paul Elliott]

It looks like you want the track to bend (sharply?) aft, port and starboard. This way you could lead the sheets aft for a better lead angle when using a larger headsail. Correct?

On a regular non-self-tacking headsail, there are often tracks for the lead blocks, and these location of the blocks can be adjusted, either with pin-stops or with control lines. But with a self-tacking arrangement, when flying a smaller headsail you would need stops attached to the track that would keep the sliding blocks from traveling to the end of the track. There is hardware that will work for this.

In your diagram however, the sharp angles in that track aren't going to let you use regular track-mounted blocks -- they can't turn sharp corners. Also, if you solve the "corner" problem the forces on the jibsheet look like they would prevent the block from reaching the end of the track. Instead, the block would stop near the corner anyway.

I've not sailed with a self-tacker, but the regular two-sheet arrangement is fine with me. It's good for my upper-body strength.

[Sailmonkey]

Ok, a second look has lead me to believe I may realize what you’re asking about.


There is no car that can make sharp corners like that.

Self racking headsails are typically higher aspect efficient shapes......you don’t get this by having the sail rolled partway up.

The added complication of lines needed to control a theoretical car able to transition these turns would nullify the ease of sailing gained by having the self tacker.

[Matt Johnson]

Also, the forward part of the track is the wrong shape. From the forestay, figure out the sheeting distance you want the track (your radius) then draw an arc keeping the same distance away from the forestay.

A better way is to use vertical curve with the ends higher then the middle.

Matt