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If the bow is not up, you are not planing, no matter how fast you are going.

Total tosh  this guy has never been on a planing sailboat.

daddle just in case you ever DO find youself on a planing sailboat the place to be is as far back as possible to keep the bow UP.

 

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15 minutes ago, TQA said:

Total tosh  this guy has never been on a planing sailboat.

daddle just in case you ever DO find youself on a planing sailboat the place to be is as far back as possible to keep the bow UP.

I suppose one should precisely define planing? Exactly where on the power/speed curve is one planing. Until then we just have a ridiculous forum spat. DO my 12,000 plus miles on a SC50 count? Or the sportboats before that?

Why does one significantly unwind the throttle of a dinghy when it accelerates onto a plane? Perhaps that Wikipedia curve is more variable than indicated?

As far as bow-up or bow-down, one does whatever gives the desired results.

 

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?? Crash, The bow must be up to plane ?

We had the nose buried every time we caught the wave in front (and as Lydia said I forgot to pull the cruising anchor out of the bow locker) 

We had enough power to push through it, boat speed didn't drop below 15 when we were buried. Waterline length of 40'.

Genuinely curious. Does that mean this isn't planing? 

 

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3 hours ago, shaggybaxter said:

?? Crash, The bow must be up to plane ?

We had the nose buried every time we caught the wave in front (and as Lydia said I forgot to pull the cruising anchor out of the bow locker) 

We had enough power to push through it, boat speed didn't drop below 15 when we were buried. Waterline length of 40'.

Genuinely curious. Does that mean this isn't planing? 

 

Most likely flow was detached from hull throughout the extravaganza if you maintained fun-factor-15, so yes - you were planing. That is unless your submerge-detection system on your hyperdrive activated during each dive and meant relativity played havoc and your hull greatly extended temporarily in order for you to have a 15kt design hull speed, then snapped back to normal when the spume cleared. Or perhaps the boat is floppy enough that the hull form was under such pressure that for each dive it flexed into a non-displacement hull form temporarily.

But I think you were probably just enjoying a good plane.

 

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I agree with Carcrash.

Speed has little to do with whether a boat is planing, even though a lot of people like to think so.  A narrow low wave dag hull (like on multis)  are capable of very high speeds, but I don’t think I’ve ever heard anyone refer to a multi planing.

Planing requires lift.

There has to be a positive AOA in order to generate lift and generally speaking only the front half of a boat has positive AOA. The stern has negative AOA so generates suction rather than lift.  However a wide shallow stern will generate less suction than an IOR type stern resulting in greater net lift (bow lift – stern suction). 

So while a wide stern won’t generate the lift required for planing, it can certainly promote planing.

If you want to know if a sailboat is planing - pay little attention to videos looking aft or shots of the knotmeter.  Look to the bow – because that is where the lift is generated

In the video of the Moore, the water spraying off to the side looks like it has been shot out of a fire hose – indicating a lot of pressure and lift.   So it looks to me like  the Moore is definitely planing.

FWIW we had my old 27 footer cranked up over 14 kts under jib & main going down some waves, but I never considered it planing, just really heavy surfing in that particular case

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