"I also agree that the sealline system has some serious shortcomings, especially the fact that it retracts vertically and not flush with the rear deck. This is a recipe for disaster in even the smallest surf, because the rudder will be mangled on the bottom if the kayak flips over. It's also a problem for cartopping and for carrying the kayak. For such an expensive system, I would expect much better in at least this aspect." snip.... I am not sure if you have looked at this system, but the blade is very different from usual rudder systems because it is much smaller. The pivot point for the rudder is lower than a conventional system so consequently it does not have to drop down as far. When the blade is retracted it comes up from the lower pivot point and it is shorter so it doesn't stick up very far at all. I didn't measure it but it didn't extend much farther from the deck than a conventional rudder. It has less surface area so there is less wind drag when it is up. Take a look at the link, it explains the lower pivot point and smaller blade. http://www.cascadedesigns.com/sealline/smarttrack_bladehousing.asp The other thing I liked about the system was that the blade has a spring that causes the blade to retract if you forget to take up your rudder when you get into shallow water or get into heavy bull kelp, less chance for damage and no kelp hanging off the rudder. You can set the blade for different tensions. -- MZ website: http://members.home.net/mzuschlag *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
>[Mary] >I am not sure if you have looked at this system, but the blade is very >different from usual rudder systems because it is much smaller. That means that is too short. The blade I have on a rudder with the same approach (vertical stowed blade) stood miles up in the air. The pivot could not have been any lower or it would have been under water, the support block usually touched the water, and the blade could not be any shorter to be effective. If the pivot is any lower there won't be enough mechanical strength/support for the blade which will bend or split the mounting block. > The pivot >point for the rudder is lower than a conventional system so consequently it >does not have to drop down as far. If you put one of those on a Sea Yak the blade wouldn't even get wet - too short to reach the water. > When the blade is retracted it comes up >from the lower pivot point and it is shorter so it doesn't stick up very far >at all. I didn't measure it but it didn't extend much farther from the deck >than a conventional rudder. That means it would only be long enough on a high decked kayak if the whole unit was mounted at water level otherwise the blade is too short for anything other than flat water paddling. > It has less surface area so there is less wind >drag when it is up. Even less efficient no matter how good the foil shape is. >The other thing I liked about the system was that the blade has a spring >that causes the blade to retract if you forget to take up your rudder when >you get into shallow water or get into heavy bull kelp, You mean drops the blade into the water, a string pulls it up(?). We do mean retract when we pull it out of the water? A properly designed system allows "kickup" at some predetermined load. The spring is a high-tech equivalent of a bit of bungy. Alex . . *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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