PT Sailor Posted February 16, 2011 Report Share Posted February 16, 2011 Hi Just wanted to get some advice on rudder sytems for the PT. Is there anything commercially sold that will suit it or do they normally have to be custom made? I have been looking at the Dotan system which seems like it works well (although expensive) and they have sent through photos of it attached to a Paper Tiger. Has anyone had any experience with the Dotan system or can you recommend something similar? I would prefer not to have to make up one myself if I can purchase a complete system. Any photos of current set ups would be much appreciated. Thanks Link to comment Share on other sites More sharing options...
tonyquoll Posted February 16, 2011 Report Share Posted February 16, 2011 The standard gear includes; - Carbon blades by Larry Fay, Dandenong (03) 97921227. Also ask Hyperfoils, John Pinkerton NSW (02) 42294053 - Aluminium Stocks by Mal Willis, Ballarrat (03) 53356251. - The Kiwis use carbon ones: built to order by Scott Pedersen NZ$1000 email; scott.pedersen1@gmail.com - blocks to mount pintles in vertical line (not flat on transom), with a pulley mounted into the top block, so pull-up rope leads to rear beam. At rear beam a cam-cleat mounted on the forward side. - alternative is custom-made pintles, with built-in pulley; Vic Scholes, Latrobe Valley (03) 51696295 Above contact details taken from sources a few years old, sorry if they're out of date. See pics and more info at: http://www.papertigercatamaran.org/index.php?option=com_kunena&Itemid=69&func=view&catid=13&id=131 Link to comment Share on other sites More sharing options...
PT Sailor Posted February 17, 2011 Author Report Share Posted February 17, 2011 Thanks for the info Tony. I have uploaded a couple of pics of the Dotan system on a PT. What are your thoughts on this? It seems like a good design that is very easy to use Cheers Link to comment Share on other sites More sharing options...
PT Sailor Posted February 17, 2011 Author Report Share Posted February 17, 2011 Here are a few more images. Link to comment Share on other sites More sharing options...
tonyquoll Posted February 17, 2011 Report Share Posted February 17, 2011 Haven't ever seen it used. Based on the photos; - looks heavy; not good. Any spec on the actual weight? - they haven't adjusted the pivot axis to vertical; but easy fix; couple of wedged blocks between transom and pintles. - hulls & other gear in shot 1980's vintage - wonder of that kid as ever seen again? He's sitting on the wrong side of the boat, in irons, twisting the tiller extension and wondering why the boat isn't turning. Dad, you're busted! Link to comment Share on other sites More sharing options...
PT Sailor Posted February 17, 2011 Author Report Share Posted February 17, 2011 They have the weight of the assembly as 0.78 kg each and the rudders are 1 kg each so you are looking at under 4 kg for the lot Link to comment Share on other sites More sharing options...
tom Posted February 23, 2011 Report Share Posted February 23, 2011 That's about 1kg over a typical rudder system on a top PT. I actually think the Dotan is quite a neat system, but i did look at the price a couple of years ago and it was crazy expensive to get a set landed in Aust. (the stong dollar might have helped now though?) Link to comment Share on other sites More sharing options...
PT Sailor Posted February 23, 2011 Author Report Share Posted February 23, 2011 Yea they are still pretty expensive but the dollar has helped and I think they now have a distributor of them in NZ which is helping reduce the shipping costs. Agree that they are a pretty cool rudder system. Every kilo counts I suppose, but I do wonder how much of a difference an extra 1 kg would make over a race. Link to comment Share on other sites More sharing options...
tonyquoll Posted February 23, 2011 Report Share Posted February 23, 2011 more expensive, heavier, and requires you to be near the rear beam to lift the rudders... can understand why aluminium boxes and remote cam-cleats have become most popular. The really trick ones run a tube through the hull so you can lift a rudder via control at the front beam; great for clearing weed in light wind races Link to comment Share on other sites More sharing options...
tom Posted February 23, 2011 Report Share Posted February 23, 2011 The fiberglass rods are the lightest and simplest method, they just suck when it comes to clearing weed.. I'm working on a system that uses a spring to keep the rudder in the down position, and you pull a rope to raise it against the spring pressure. That way if anything fails (other than the spring) the rudder is in a useable position, and you don't have to worry about pulling it all the way down. To clear weed you just pull on the rope and release, only need to cleat when you want t to run with one rudder. When i get back out sailing i can verify the spring tension against the load on the rudder tip on a screaming reach! Link to comment Share on other sites More sharing options...
tonyquoll Posted February 24, 2011 Report Share Posted February 24, 2011 personally I hate those fibreglass rods: on a borrowed boat I was coming into the beach fast, downwind. Planning to round up near the shore, the rods oblige me to face backwards and sail blind as I release one rudder. Look forwards again and begin rounding up, look back to release the other rudder; but there's a fair bit of compression force required to release it, and now I cant see or steer...BANG!!! We've just hit a large rock and parked the boat about 1m in the air, on top of it. Luckily the damage was easily repaired with some Epifill. the convention is to pull the rudder down, and have some elastic flick it up when the tension is released. There's a 2:1 pulley system pulling it down; so you can apply 40kg or so of force to pre-stretch the rubber or whatever is built into the system (for bouncing off jellyfish or accidents). The beauty of this is that once cleated, it doesn't matter how much more force is applied by drag when sailing at speed. The down-side Ive found, is that all the tension has a vertical component, tending to pull the rudder box up the transom. All the force bends crap out of the little pins which hold the rudders on! Tom, maybe of the spring system included a ratchet, so that it can be locked in place once down? I noticed some of the kiwis have an even simpler system; just stick a pin through the box & blade once the rudder is down, pull it out and the rudder can come up Link to comment Share on other sites More sharing options...
tom Posted February 24, 2011 Report Share Posted February 24, 2011 I agree on the vertical component of the conventional layout pull down system.. That was the reason for the tubes through the hull in the first place. I have used a lot of different rudder systems, (including a pin through the blade and box!). - lever on top of rudder stock - fiberglass rods - pulley system and cleat incorporated on stocks - pulley system and cleat run forward through the rear beam with cleat on front of rear beam - pulley system run forward to cleat on front beam - through hull rope and pulley system to cleat on front beam They all have pro's and cons, and all have featured on boats that have won national or international series, so i don't think any one will make a massive difference.. It would be nice to have something with fewer moving parts, that is what i am looking for. The PT is already one of the most complicated cats around. (I'd go for the pin through the rudder, but it's a bitch when there is weed around....) Link to comment Share on other sites More sharing options...
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