Tuesday, April 7, 2009

Tech Tuesday: Carbon Tiller Extension Comparison

Tech Tuesday is our feature here at the Stern Scoop where we plan to highlight some of the more technical aspects of some of our products. From line specs to how to properly rebuild a winch we hope to provide some fodder for the tinkerers and engineer types out there.


Today we're starting with some detailed specs on carbon tiller extensions. We offer seven different types with rubber universals (there are some larger big boat extensions made of carbon as well from Forespar). From top to bottom we have the Acme Fatso, Acme Fatso Jr., JCD, Ronstan, Forespar Giant Stick, Forespar Big Stick and Holt Allen. I threw a quarter and a dollar bill in there for a size comparison.

We felt that the two most important measurable qualities of carbon tiller extensions were their stiffness and their weight. To that end we've crunched the numbers and come up with the following results. All the extensions measured were 48" or the closest length the manufacturer makes (+/- 1" or so). You can click on each product for more details like cost and diameter.

ProductWeight (oz)Deflection (inches)
Acme Fatso7.71/8" (Best)
Acme Fatso Jr.5.89/16"
JCD9.27/16"
Ronstan6.71 7/8"
Forespar Giant Stick6.95/32"
Forespar Big Stick7.57/16"
Holt Allen5.5 (Best)7/8"


We measured the weight of the extensions on a postal scale. To measure the deflection we supported them at both ends and hung a 26lb weight from the center point of the extensions. Kudos to Ian for developing this testing rig and doing all the deflection measurements.

While I think with more time and an engineering degree a more accurate testing process could be devised I think we've provided an accurate means by which to determine relative weight and stiffness for these extensions.

Grip and diameter are a matter of personal preference. Obviously the thicker extensions performed better in our deflection test and tended to be heavier (although the Forespar is actually lighter). The Holt Allen and Ronstan's have foam grips and the JCD has basically a rope wound around the end which is then shrink wrapped. The Acme and Forespar extensions have a textured sandpaper like feel.

The picture above is of the Ronstan which obviously had a bit more bend than the others. The Ronstan is also the only tapered extension so that might be related to the bending.

Which one is the best? I think based on the numbers the Acme Fatso Jr. looks like the winner to be with the best combination of stiff and lightweight. I prefer the textured grip of the Acme and Forespar over the foam but again that's more of a personal preference. If you want a larger diameter to hold onto the Forespar Giant Stick is a great choice as well.

7 comments:

  1. I've used an Acme Fatso for years on Snipes, Finns and Stars. The oval shape of the grip is very comfortable, but in my mind the best part is the universal. The extension actually spins relatively freely on the universal, so you can keep a firm grip on it through tacks rather than have to loosen your grip to let the extension slip around in your hand. It's hard to explain, but it is great to sail with.

    ReplyDelete
  2. I think you've overlooked a couple major factors in high end tiller extension use, both involving the universal. Several years ago JCD conducted extensive tests on the available universals. They found the Windesign (actually Optiparts) to be the strongest, longest lasting universal available. It's not rubber, it's urethane and has a rope core. Why? If you're not attentive to cracks in the universal (as soon as you see one its time to replace it) the extension will stay attached due to the rope core. No other extension above has that feature. Second, JCD has the absolute best swivel (and I'm not sure if any of the others even DO swivel other than the Fatso which doesn't swivel well. I also know that JCD extensions are all meticulously hand made by the man himself John Cuccio. I've used them for years on my Etchells and my Laser and wouldn't have any other!

    ReplyDelete
  3. I have used the Acme Fatso on lasers for a long time until last year when I went through three of them. All breaking in the same spot ( mostly as a result of high speed crashes downwind). I switched to the JCD on the recomendation of another laser sailor. While it is heavier it is basically indestructable and JCD can customize the lenght if you wan tto.

    ReplyDelete
  4. I made my own out of 0deg braided uni carbon over a square mandrel, all tied together with glass yarns on the 45. It is super light and very stiff. It's a fun project and not really very difficult for those that like to build things.

    ReplyDelete
  5. Don't forget that the Forespar has the patented "Speed Lok" universal which means if the universal breaks (wears out) a new universal can be changed out simply by removing the old one with a wrench and putting a new one in for $7.00! No messy epoxy work.

    ReplyDelete
  6. The JDC universal is very nice, but their extensions are very heavy and I dont like the grip either. The Holt Allen extensions swivel better than the acme, but not as well as the JDC. Holt is the only one that makes a telescoping carbon extension which is the top choice in the 505 class.

    ReplyDelete
  7. The Forespar u-joint spins very well and can be replaced quickly and I keep one on the boat for an emergency. I preferred the old Forespar graphite stick for my J/22. It was stiff, but more flexible than my Forespar Giant stick. I liked the Giant stick feel and lightweight design, but it is a fragile design. Broke after it got a few dings in it. The Graphite design is tough, but Forespar doesn't make it anymore.
    Back to the u-joint, the speed-lock is easy on and off which saves on the wear if you remove the stick after each race. I have converted sticks to the Forespar u-joint just for the ease of use and feel.

    ReplyDelete