What caused my boat to flip?

[slower but cooler]

First of all this happened many years ago and everyone is fine but we've never really been certain of the cause. Cruising across the lake at about 40-45mph in light chop going straight with five people on board. Without warning the boat rolls hard onto the right chine, shoots 90 degrees left and rolls over. Motor was running fine at the time it happened and didn't seize. First guess was that we'd wrapped something around the prop shaft. Nope. Second was that we'd peeled some glass off one side of the bottom. The boat is glass over wood. Nope. Third guess is that the v-drive shifted. We didn't have bracing on the gear box mount and noticed cracking of the stringers after the crash. Steering wheel never moved in my hand. I tried to correct but the boat had its mind made up. Steering was all intact after crash. We had drive rebuilt after crash but shafts were spinning freely. It is a Menkens gear box. Any guesses? The boat ran great as designed for about 40 years prior to this happening. We are in the planning phase of building another one so if there's something we've overlooked we want to correct it on this one. As many of you know, flipping a boat just isn't that much fun.

[Rattle Can Lou]

Hey tooney, is that you?

[yopengo]

:idea:
http://www.***boat.com/forums/attachment.php?attachmentid=41797&stc=1&d=1193253073
:D :eek: :)

[Rage28]

What kind of boat? What kind of steering? (cable, hydraulic, other...)

[Sangster]

Hey tooney, is that you?
:jawdrop: :jawdrop: :jawdrop:

[slower but cooler]

Cable steering, but all in working order after the crash. We even ran the boat a time or two after the crash. Steering worked fine. Boat is homemade, 16' flatbottom (not quite deadflat at transom), 6' beam. At the time it was powered with a stock olds 455.

[slower but cooler]

It could have been Nessie. Crash was at Millerton Lake. No shortage of large dead fish on the surface. I'm not sure who Tooney is. Are you missing an elf?

[Moneypitt]

Severe case of bow steer???..How deep was the water? Hidden cable/tree branch..........?.....MP

[pgf127rt]

With 5 people in the 16' boat how was the weight distributed, was one passenger sitting on the right side of the front deck?

[slower but cooler]

Boat had two forward facing benches. Weight was even across rear bench. The guy sitting on the right was heavier but front bench was empty on the right side. Water was deep. Very deep. Happened out in the middle of the lake. No obstacles anywhere near there. The boat did have a tendency to be twitchy on dead calm (glassy) water. But here it was light chop 1' or less and speed was low. We are pretty sure it wasn't anything engine related or steering related. Since the hull really didn't have any exterior damage we assumed that either the gear box had seized up (but the shafts spun freely) or that cracks in the stringers allowed the gear box to twist and temporarily bind a shaft. It still remains somewhat of a mystery so I wondered if anyone else had a similar problem and knew what caused it. I enjoy reading all the threads. I've sure learned how wrong we've done things in the past.

[ol guy]

boats don't decide to do a belly flop for no reason.

[Rage28]

The way you described the crash it sounds like rudder flutter caused by the streering cables being to loose. When the rudder loaded, one side of the cable gets real loose with allot of slack, then you corrected and the rudder snapped the other direction taking out all the slack causing the boat to react the way it did.

[fastvdriver]

my 2 cents is bow steer!!!! 16ft boat with 5 people in it boat is going to be sitting deeper in the water. you said the boat would move around on glass water saying that it already had some issues with the strakes or the rudder.

[Sanitariumflat]

If it rolled on to the right chine, why did it hook 90 degrees left? Shouldn't that have made it hook right due to increased drag on that side of the boat? Or am I missing something. Just curious.

[slower but cooler]

No you're not really missing anything except it rolled onto the right side so hard that the shape of the boat (curve at the bow) simply shot the thing to the left. Since it was already rolled onto the right side it rolled over port side over starboard. It was very strange. I've never had a boat act anything like that before. Of course most the boats I've driven were capable of maybe 70-75mph on a good day. Going straight at 40-45mph I never was expecting something like that to instantly happen. Just thought someone might have had something similar happen and been able to pinpoint the cause.