Nearly rolled my boat--how/why???

[dicktaber]

Still kind of a newbie, started boating last summer with a nice, slow (25 mph) 15' tri-hull. Last winter I bought a 1972 17' v-hull Crestliner with a 115 HP Merc. Ah, horsepower heaven! While out testing it with the previous owner (I was driving) when I got a bit of speed on it I was messing w/the power trim; the bow skipped quickly left/right/left--felt a bit like a tankslapper on a motorcycle. I pulled the power to idle, everything returned to normal, just figured it was my lack of experince. Read some stuff on chine-walking but it didn't seem to describe what I experienced. I've had the boat out a number of times this summer, generally taking it easy, and it rides much better/smoother than the tri-hull, but coming back in last week around 30 mph, I hit a wake running nearly parallel to me while I was messing with power trim (another new-to-me deal). Boat rolled to left almost 60 degrees (rub rail IN THE WATER) and stayed there as I gently tried steering and trim inputs to no avail. I pulled back on the power and the boat righted itself as it slowed. What the **** happened? I let my heartbeat slow down below 9000rpm and took it easy the rest of the way in. This weekend I was very careful, monitoring wakes, trim and speed, and at one point almost did it again--this time it rolled to one side then the other very quickly--I pulled the power off and all okay again. Once again this was while I was trimming. I see boats going past me all the time, at higher speeds and slamming through every wake around. What am I doing wrong? What attitude should the boat carry at on-plane speeds? Am I running too nose-low or too nose-high? I try to find a stabilised speed, say 30 mph, then trim so the steering effort feels equal in both directions. Guess I still have a lot to learn--anyone have any input? I find it really difficult to trust/enjoy the boat, and every time I reach for the throttle my girlfriend white-knuckles the grab rail..mostly we just putt around the lake right now.

 

[mellowyellow]

Re: Nearly rolled my boat--how/why???

not sure I have an answer, but what is the max HP<br />rating and load capacity for this boat?

 

[dicktaber]

Re: Nearly rolled my boat--how/why???

Boat is too old to have a placard (subject of a previous post) but using other owners of same model and USCG formulas, should be good for 150-175 HP and there are only two of us in a 17'er, so we are well within the weight and HP limits, and we're only talking 30 mph here...

 

[mellowyellow]

Re: Nearly rolled my boat--how/why???

always start with the obvious... are you carrying a lot of "unknown" water in the hull making her<br />extra heavy? is the cavitation plate on the motor<br />even with the bottom of the boat? if you set trim and leave it, will it still happen?<br />a little scary dude <br />PS. I have 16', '72 sea sprite w/115merc 1150 w/o power<br />tilt/trim and have never even come close to this happening...

 

[dicktaber]

Re: Nearly rolled my boat--how/why???

Thanks for the ideas--<br />1) the underfloor foam (those parts I can reach) are dry. <br />2) The cav plate (with doel-fin attached) is about even with bottom of "v" in hull. (Hmmm, maybe the doel-fin is "holding" me sideways once the boat starts to roll? Maybe try taking doel-fin off?...)<br />3) Set trim and leave it alone...worth a try, but where do I set it to begin with?<br />BTW, you're right, it was scary--fifteen years of military flying and 30+ years of riding/racing motorcycles and this ranked waaay up there...probably 15-20 seconds of waiting for the worst to happen and trying to find a way out of it, but if felt like much longer. Kinda like when I was 16 and driving way too fast on iced up roads...then the car comes around and I've got all this time to wait for some solid object to stop me...and all this time to think, oh, sh****t...

 

[Jango]

Re: Nearly rolled my boat--how/why???

First, I would suggest, you should leave the Dock with the motor trimmed ALL The Way DOWN. After, you are up on plane, begin trimming UP or Out until the boat attains Max Speed without Porpoising (bouncing). <br />If you are in choppy or rough water TRIM DOWN to keep the nose of the boat low in the water. Left or Right steering pull is not necessarily due to Up and Down Trim.<br />Try to approach waves and other choppy water as close as perpendicular as posible until you learn the characteristic of the Boat.

 

[DJ]

Re: Nearly rolled my boat--how/why???

Knot2much,<br /><br />Ah hah!! Doel Fin!! Usually these (and others) are quite helpful, however they can cause real handling concerns on some hulls. Especially if the engine is installed at the lower range on the transom (X-dimension).<br /><br />I would try removing it. Don't bother filling the holes yet. Just put some truss head bolts in the holes with the bolt heads facing down. This will keep water from coming up through the holes while you try it out.<br /><br />Once removed:<br /><br />1. Accelerate with the engine trimmed down.<br />2. Once on plane, trim the engine up until the steeering "feels" right. Each boat is different, you'll find what works best.

 

[dicktaber]

Re: Nearly rolled my boat--how/why???

You guys are the greatest! That thing (doel-fin; I think it's actually a Sting-Ray)) is coming off tonight and if I can get to the lake this week I'll post and let you know--otherwise it will be the weekend. Funny, I've never read anything but rave reviews about hydrofoils on this forum. Thanks for the tips on trimming--I usually putt out trimmed up to avoid bottom junk (shallow channel) then try to get the motor "level" by eye, then accelerate up on plane and then adjust from there. I'll start with it all the way down next time.

 

[chrker]

Re: Nearly rolled my boat--how/why???

I think Jango nailed it. You should not cross wakes that are parallel to you, always cross them at an angle (usually not less than 45 degrees). When crossing parallel wakes, a V-hull will naturally want to drop down into the valley of the wake as the keel crosses over the crest. With V-hulls, the beam and deadrise of your hull will effect how much the hull rolls. For example, a narrow beam and a high degree of deadrise will roll more than a wider/flatter hull. Additionally, your freeboard will also play a role in regards to how close the water comes to the rubrail during a roll. You may have gotten away with this in your tri-hull but your V is a different animal. <br /><br />Regarding the first incident with the bow walking left to right to left again, without having all the information, it sounds like you might have been a little too bow down (trimmed in) and the motion of the water might have been "steering" your bow. Not sure though. <br /><br />Good Luck, <br />-Chris <br /><br />P.S. My personal opinion is that the hydrofoil is not the issue. If anything, it should somewhat lessen the effects of a roll due the resistance of the water on the surfaces of the wings. But, you should probably try it without it anyway.

 

[Beernutz]

Re: Nearly rolled my boat--how/why???

Stingrays provide a lot more lift than Doelfins. They act like a spoiler, due to the long turned-down trailing edge. That could very likely be your problem.

 

[Beernutz]

Re: Nearly rolled my boat--how/why???

K2m, That "tank-slapper" reference got my attention in the middle of the night. Been there..done that. Gettin' pitched over the high side ain't fun! I guess what I'm gettin' at is that sometimes we overlook the obvious.<br /><br />Check to see that both ends of your steering cable outer cover are securely fastened to the steering gear and the tilt tube of the motor. There should be no movement at either end. Also, make sure there's no slop in the linkage between the cable and the steering arm of the motor. Have your girlfriend jog the wheel back and forth while you inspect the connections.<br /><br />Just another thought. Now I can get back to sleep.

 

[EatMoreFish]

Re: Nearly rolled my boat--how/why???

grab the motor with it would and shake it from side to side. Is it loose? could it be moving for side to side?