Flat cornering and Fins

[55Crestliner]

What makes some boats stay flat when turning, while others (most it seems) bank into a turn?<br /><br />What exactly does a skeg or fin do to a boat when mounted midships?<br /><br />The boat I run is a '50's Crestliner, but I also have a Feathercraft. I've seen old photos of racing Feathercrafts with a small fin under neath that can be seen when the boat gets airborne. What would a fin do to my Crestliner? (besides slow it down )

 

[KCook]

Re: Flat cornering and Fins

Amount of bank depends on the turn. Biggest differences are seen in sweeping turns on plane. In very tight, slow turns they pretty much all bank into the turn.<br /><br />Kelly Cook

 

[Dhadley]

Re: Flat cornering and Fins

It has to with hull design. As a very general rule of thumb, the deeper the V, the more it will bank. Tunnel boats (cats), generally, will stay flat. <br /><br />I had a 20' Can-Am (Warlock) ski boat that just would not bank at all. It was a V bottom but had reverse chines. It was amazing how hard that boat would turn.

 

[55Crestliner]

Re: Flat cornering and Fins

So what does the fin do? Just keep it from slipping?

 

[sangerwaker]

Re: Flat cornering and Fins

The fin does also help with the leaning in the corners (or lack of). Ever ridden in a tournament ski boat? They all have fins underneath and stay very flat while cornering. The fins are also there to help with sideways pull from a skier who cuts hard while way outside the wake.

 

[55Crestliner]

Re: Flat cornering and Fins

Well that completely makes sense with a ski boat, I've seen them when they have several under there. With my VERY limited experience skiing, I see why you'd want them. I'm just not clear on what they would do for a small boat doing turns?<br /><br />This somewhat answers my question...<br />

<br />But would this make the boat lean more or less in a sharp turn - I understand it would help reduce slip.

 

[sangerwaker]

Re: Flat cornering and Fins

I'm not completely sure either. But I'm pretty sure they would minimize any leaning you are getting. It does add drag and slow your top end down. Kind of a trade off.

 

[JasonJ]

Re: Flat cornering and Fins

On a small boat, the fin would help prevent the back end from sliding out, allowing you to turn tighter. Generally a flat or minimal deadrise hull will benefit from this. A V hull would not benefit because essentially the entire keel acts to keep the boat from sliding. I personally prefer a boat to lean in turns, it makes it safer and less likely to eject someone.

 

[sangerwaker]

Re: Flat cornering and Fins

Jason does bring up a good point. I have nearly ejected someone from my boat. I have only driven and ridden in ski boats with fins, but they do turn VERY sharp and can easily send someone for an unexpected swim...or worse.

 

[55Crestliner]

Re: Flat cornering and Fins

Real good point - excessive leaning won't eject someone - might take a little water over the gunwale, but that's better than sending a kid for a swim.