punchn2 Posted January 16, 2009 Share Posted January 16, 2009 i have a 7mt plate cuddy cab which broaches in a following sea and when the wind and chop is against the back qaurter, to me it feels like i cant get the nose up high enough even when i trim the motor up to lift the bow and that helps a bit, i have minimul weight up front and in the cabin except for the crew, my question is, would fitting a perma trim allow me to trim the motor up therefore pushing the back down and lifting the nose higher than the standard motor will allow .... Link to comment Share on other sites More sharing options...
gone_wishin Posted January 16, 2009 Share Posted January 16, 2009 Hi Punchn2, I don't think a permatrim would help your situation but I'm no expert. I have a permatrim on my boat, I got it to help reduce porpoising and get on the plane quicker and stay there longer. It has done that for me, I would think probably trim tabs would be more suitable for what you want to achieve. Link to comment Share on other sites More sharing options...
punchn2 Posted January 16, 2009 Author Share Posted January 16, 2009 Hi Punchn2, I don't think a permatrim would help your situation but I'm no expert. I have a permatrim on my boat, I got it to help reduce porpoising and get on the plane quicker and stay there longer. It has done that for me, I would think probably trim tabs would be more suitable for what you want to achieve. trim tabs wont help get the front up at all... trim tabs help to level out the stern and keep it on the plane, well thats my understanding... thanks for the input though Link to comment Share on other sites More sharing options...
Dreamtime Posted January 17, 2009 Share Posted January 17, 2009 Trim tabs can be used similar to brakes on a car. Dig them in to slow you down in a following sea. Link to comment Share on other sites More sharing options...
Geoff Posted January 17, 2009 Share Posted January 17, 2009 The reason for broaching is the wave is traveling faster than the speed of the boat. Once the wave picks up the boat , the boat is now traveling faster than the motor speed you are , in essence, at the mercy of the wave. Trimming the motor , fitting a foil , regardless of the brand , or trim tabs will make little ot no difference. There are really only two choices , slow down so the wave is unable to actually pick the boat up , so to speak , or hit the throttle & with the motor now more powerful (faster) than the wave "drive out" of the situation. Driving out can be dangerous especially if the boat is already starting to broach. The trick is to watch the waves in front & decide should I back off or increase the throttle just enough to match the wave speed or perhaps a little more. This will provide sufficient stearing to keep the boat straight Geoff Link to comment Share on other sites More sharing options...
punchn2 Posted January 17, 2009 Author Share Posted January 17, 2009 The reason for broaching is the wave is traveling faster than the speed of the boat. Once the wave picks up the boat , the boat is now traveling faster than the motor speed you are , in essence, at the mercy of the wave. Trimming the motor , fitting a foil , regardless of the brand , or trim tabs will make little ot no difference. There are really only two choices , slow down so the wave is unable to actually pick the boat up , so to speak , or hit the throttle & with the motor now more powerful (faster) than the wave "drive out" of the situation. Driving out can be dangerous especially if the boat is already starting to broach. The trick is to watch the waves in front & decide should I back off or increase the throttle just enough to match the wave speed or perhaps a little more. This will provide sufficient stearing to keep the boat straight Geoff Geoff thats accurate, but ive found the safest thing to do in my boat is power over the wave, thats fine, its the chop thats very steep n close together which causes the trouble as my bow burys itself into the chop n the wave or chop behind me pushes my stern, so if i can get my bow higher id skip over the top of the next wave or chop.... if ya know what i mean... Link to comment Share on other sites More sharing options...
pelican Posted January 17, 2009 Share Posted January 17, 2009 (edited) The black art of props may help as a 4 blader may enable more trim and hold (more grip) at a lower speed , lift for transom at higher speed) and also more rake on a 3 blader can do the same . Speak with someone who can check your boat is set up right to start with then speak to the weird blokes who know their props. Permatrim can help support the stern and create a lower planing speed that may help you not get to the point where you are on and off the plane so much between waves in a following sea and have a lesser occasion to broach. But when you do it won't help and the wing style cav plate mounted ones are reported as making a broach worse once it has started as there is additional water pressure on top of them or they are digging in. Just how bad is the broaching and in what size seas at what speed? Having spent a lot of time in displacement and semi planing boats ( different hull shape and characteristics) you do get used to a certain amount and learn to correct it early naturally as it is more comfortable before it becomes a full on broach ( like sliding sideways down the face) but some planing hulls are classics for doing it in small seas. Have lump in throat just thinking about it as it never feels right when it is happening. Edited January 17, 2009 by pelican Link to comment Share on other sites More sharing options...
punchn2 Posted January 17, 2009 Author Share Posted January 17, 2009 i have a 4 bladed prop, the broaching happens when i have 20+ knots of wind behind me and anything over a metre of chop Link to comment Share on other sites More sharing options...
Geoff Posted January 17, 2009 Share Posted January 17, 2009 Geoff thats accurate, but ive found the safest thing to do in my boat is power over the wave, thats fine, its the chop thats very steep n close together which causes the trouble as my bow burys itself into the chop n the wave or chop behind me pushes my stern, so if i can get my bow higher id skip over the top of the next wave or chop.... if ya know what i mean... Yes , I can see where your coming from. From my experience it's an natural reaction to have the nose plough into the next wave as the bow has a tendancy to be facing down at the time & as it digs in & the boat slows , the trailing wave catches up & the broaching occurs. I find in these conditions it's one hand on the stearing & the other on the throttle. As the boat nears the bottom of the wave trough hit the throttle which should lift the nose sufficently to drive over the top of the next wave. The timeing & amount of throttle for this reaction is all important & can vary from wave to wave If it is lift your actually looking for then a foil like a Permatrim may not fix the problem but will certinally assist Geoff Link to comment Share on other sites More sharing options...
punchn2 Posted January 17, 2009 Author Share Posted January 17, 2009 Yes , I can see where your coming from. From my experience it's an natural reaction to have the nose plough into the next wave as the bow has a tendancy to be facing down at the time & as it digs in & the boat slows , the trailing wave catches up & the broaching occurs. I find in these conditions it's one hand on the stearing & the other on the throttle. As the boat nears the bottom of the wave trough hit the throttle which should lift the nose sufficently to drive over the top of the next wave. The timeing & amount of throttle for this reaction is all important & can vary from wave to wave If it is lift your actually looking for then a foil like a Permatrim may not fix the problem but will certinally assist Geoff spot on geoff, i drive the boat as you say... i really think i jus need a bit more lift to power over the next wave that my bow is dipping into Link to comment Share on other sites More sharing options...
Geoff Posted January 17, 2009 Share Posted January 17, 2009 spot on geoff, i drive the boat as you say... i really think i jus need a bit more lift to power over the next wave that my bow is dipping into Forgot to add to my previous post Pelican's comment, the wing style cav plate mounted ones are reported as making a broach worse once it has started as there is additional water pressure on top of them or they are digging in. Totally agree , wing style foils are best avoided Geoff Link to comment Share on other sites More sharing options...
Mik Posted January 17, 2009 Share Posted January 17, 2009 Geoff Thanks for the info mate. You just confirmed for me that I've been doing the right thing. I was pretty sure I was doing ok anyway but to hear you describe exactly what I have experienced & how I learnt to overcome it is good for my confidence. I've done it once and once only, started getting sideways on the face of a following swell / wave. I got lucky that day & the conditions were sloppy, another wave came across my bow from the port side just as my port side was starting to dig in. It actually corrected me into the trough between both waves. Pretty nerve wracking stuff. I have since spent a large majority of my water time learning the handling of my boat. Confident enough now to go wide without an experienced other on board, but always weary of the absolute power of the water beneath my hull. Its a weird sensation but I think you know yourself when you are getting the hang of it. How beautifully dangerous is the sea! Link to comment Share on other sites More sharing options...
one fishes Posted January 18, 2009 Share Posted January 18, 2009 Simple, sit on the back of the wave and drive to the conditions as everyday is different trough,crest and period, match it no probs. Link to comment Share on other sites More sharing options...
ozbee Posted January 27, 2009 Share Posted January 27, 2009 you don't trim down in a following sea but you can trim down a little on the side that leans over , keeps the nose up and straight longer so less likely to broach as much Link to comment Share on other sites More sharing options...
Guest Big-Banana Posted January 27, 2009 Share Posted January 27, 2009 Fit a hydrofoil, trim up as much as you can, and get as much weight in the back of the boat. I have the same issue, a 7m plate boat and at times she can be a real pig in a following sea. We have a kill tank, which we have installed a water tank into, we fill it up on the way home and it's a pleasure to drive. Link to comment Share on other sites More sharing options...
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