Cobra/Coral Boat handling-Does Your Boat Do This???

[AlanW]

This is kind of hard to explain, so I hope it makes sense. When I take off in my boat, after it is up on the water and accelerating, there is a point where suddenly it feels like the prop loses it's bite for just a second and the hull feels real loose; and the boat "squirms" or "squiggles" or "slips" sideways. Kind of throws it off-balance for a second. It doesn't really do any harm or feel like you are gonna flip, but it gets your attention.

Now this is just my description of it and may not be what is actually happening. The boat does not lose speed or slow down, it keeps accelerating, so I don't know if the prop actually slips.

Often, as I trim up and gain speed, there are several times or points the boat will squiggle like that. Also when already going pretty good and adjust the trim up, it will often squiggle some.

Is this happening when the boat lifts up a step on the pad? Due to torque from the prop throwing it sideways during the brief second the hull frees up?

The boat is Coral 191 with 200EFI at about 9" of setback; 25 Tempest Plus @ approx 3.25" below the pad. Top speed by GPS is only around 67-69 mph, but boat has real good holeshot and very, very good mid-range acceleration.
I doubt the hull actually ever rides all the way up on the final pad step, but after reaching about 50 mph, all the water is definitely coming out from behind the boat, not any from the sides.

[Tx 201]

Yeah, that can be an attention getter!!! I haven't had it do that in a long time because I carry way too much stuff in the boat and have it weighed down too much. I probably carry 1.5 times "tournament load", and can't get the front end up enough for what we termed several years ago as the "slither"!

It isn't just the driver that feels it either! I used to know about when it was going to happen and then look over at the passenger to see their reaction. Pretty funny to see it happen to someone that isn't expecting it!!

It happens so quick and hooks up again so quick that there isn't anything from the driver's imput to be able to correct it, best way I could describe it was like hitting a patch of ice and going sideways for about 8", then back on pavement!

Put more weight up front and it will probably go away. In the meantime, have fun with your passengers!!

[TULSABOB]

Yep! That's the "COBRA SLITHER". I bet 95% of the boats do it. If yours doesn't, then you're not set up right.

[GregHeinz]

Ahh, yes, the Cobra "Slither". I'm very familiar with it. As with most Cobra owners, when I first felt it, I thought something was wrong with the set up or my driving. I remember when we came up with the name, Cobra "slither", over on the now defunct BBO board. I'm much more comfortable with the slither now, and acutally anticipate it. Once you get use to it. it won't bother you.



Modified by Greg Heinz at 10:07 PM 2/22/2007

[AlanW]

The Cobra "Slither"...I really like that, and describes it quite well. The "slipping on ice" analogy is good too. Glad I'm not crazy or the only one having this.

I think with it being winter and boats running better, I'm really getting a lot of it lately, especially running light and without the trolling motor on the nose of the boat.

I was out yesterday just running around with the boat pretty light, it was real windy, and the wind was really moving the front of the boat around at times in addition to the slithering-pretty "lively" ride!

And my wife definitely does NOT like this "slithering" when she is along

[gatorzeus]

New to the Cobra Scene, just purchased mine about 6 months ago and I ask several people about it, everyone thought I was crazy. Just put a 250proxs on the back and having to start the setup process all over again. 201s 2000 model.