Lasty Posted December 18, 2008 Share Posted December 18, 2008 (edited) I have a 40hp Johnson on a Stacer 4.5m runabout and get cavitation when I cross a wake or when I turn when the sea gets up a bit. I have lowered the motor to the last hole which made a difference but I still get some cavitation. I am wondering whether a Permatrim or other hydrofoil (I have seen the SE 200/300 Sport) help? Edited December 18, 2008 by Lasty Link to comment Share on other sites More sharing options...
brettsboats Posted December 18, 2008 Share Posted December 18, 2008 G'day Lasty It could up to a point. Have a look at your keel is it external or internal, if its external and it ends just short of your transom it could be putting disturbed water into your prop, speaking of prop whats its condition like. Do you have trim & tilt on your engine, if so, when turning is your motor trimmed in, give that a try. Brett Link to comment Share on other sites More sharing options...
Juggs Posted December 18, 2008 Share Posted December 18, 2008 I have a 40hp Johnson on a Stacer 4.5m runabout and get cavitation when I cross a wake or when I turn when the sea gets up a bit. I have lowered the motor to the last hole which made a difference but I still get some cavitation. I am wondering whether a Permatrim or other hydrofoil (I have seen the SE 200/300 Sport) help? in any boat hwhich will be used in a following sea cav plates are a last resort. i know you said youve lowered the engine, but where does the cav plate sit in relation to the bottom of the boat now? Link to comment Share on other sites More sharing options...
a boat Posted December 18, 2008 Share Posted December 18, 2008 (edited) Hi Lasty, your Stacer will have an external keel, all good alloy boats do to protect the hull if you hit something. If you are as low as you can go, yes trimming the engine fully down when turning should help. Also a SST prop, with more cupping on the ends of the blades can help if trimming in does not solve the problem. Another thing to check is with a straight edge make sure the bottom sheet is flat and does not have a "hook" or "rocker" in it-this can cause cavitation, but is rare. If you do choose to fit a foil, the only ones I like are the Permatrims, they will lift the stern up and as mentioned can burying the bow, they will not usually help with cavitation. Cheers, Huey. Edited December 20, 2008 by Huey @ Huett Marine Link to comment Share on other sites More sharing options...
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