Padstow investigation video

[SimonCh]

https://www.youtube.com/watch?v=f8sp_dcLw-A

found this quite interesting, not sure if it has been posted already. Interesting to see how the boat handles when cornered at speed, and why boats "heel in" the way they do when handled like this.

Si

[boristhebold]

Originally Posted by SimonCh

found this quite interesting, not sure if it has been posted already. Interesting to see how the boat handles when cornered at speed, and why boats "heel in" the way they do when handled like this.

Si

In certain sections of the video you can see the boat slip at certain points of the turn. I don't think all boats do this to this extent, perhaps some do. In the full report the investigation does specificaly talk about this specific boat model and year of manufacturer and implies that modifications of the hull design and tubes on this model/year of boat may have caused or increased the effect. I would advise all to read the full report especially anyone with type/year model of boat so they are fully aware. I have a slightly smaller version of this boat that but from an earlier design year which doesn't have the same hull form in terms of the (what are they called ?) hull rail thingies and my tubes dont taper so much, my boat has never slipped like this but then again ive never done a really tight turn on full power so I dont really know but then again I never would do a tight turn on full power. Anyway the full report shoudl be mandatory reading.

[SimonCh]

Originally Posted by boristhebold

In certain sections of the video you can see the boat slip at certain points of the turn. I don't think all boats do this to this extent, perhaps some do. In the full report the investigation does specificaly talk about this specific boat model and year of manufacturer and implies that modifications of the hull design and tubes on this model/year of boat may have caused or increased the effect. I would advise all to read the full report especially anyone with type/year model of boat so they are fully aware. I have a slightly smaller version of this boat that but from an earlier design year which doesn't have the same hull form in terms of the (what are they called ?) hull rail thingies and my tubes dont taper so much, my boat has never slipped like this but then again ive never done a really tight turn on full power so I dont really know but then again I never would do a tight turn on full power. Anyway the full report shoudl be mandatory reading.

strakes i think they are called mate. I have done some fast turns in my boat and it certainly heels in, but not to the extent of that video, where it turns so tight that its basically riding on the tubes. As you say - well worth a read.

[Trimix]

Wont any boat eventually slip sideways ? Once the force overcomes the grip it will slip.

Perhaps making it slip gradually rather than all of a sudden would help.

[SteveHall]

It would be nice to have this video in a downloadable format for use when instructing. Has anyone got a copy of it?

[Simon B]

Originally Posted by Trimix

Wont any boat eventually slip sideways ? Once the force overcomes the grip it will slip.

Perhaps making it slip gradually rather than all of a sudden would help.

When I train new boathandlers in our club on why trim is so important in a turn we basically do this manouvre. Without adding any trim I get them to put power on and enter a turn and ask them to tighten it until the prop loses grip and be ready to power off if anything "funny" happens.

The turn tightens speed drops, the prop loses grip then all of a sudden when the boat is not now heeled it grips again shooting them out of the turn at speed often in a different direction to what they thought.

You need dead flat water and to prepare your student, having completed this manouvre, almost all comment that they never knew trim was so important and have a renewed respect for how a boat handles.

[Doug_G]

The heel-in is caused by a combination of factors.

The angle of the prop shaft centreline to the line of the keel when turning. The greater the angle the greater the heel-in.

The leverage of the power from the prop at the bottom of the outboard leg, pushes the 'hub' at the base of the outboard outward and thus tilts the boat into the curve.
A long leg outboard on a short transom would demonstrate this very clearly.

The ability of the keel to 'grip' the water.
When the angle becomes too great the hull slips as was described.

There is a another very 'minor' effect due to prop walk, prop paddlewheel effect. This is overcome at higher speeds with a small adjustment to the steering.

[cptsideways]

My Quicksilver 435 (sportsboat) does this this with ease, it has a very shallow V angle & negative outboard strakes on the hull, it also has a tendency not to lean in corners which is very strange.

It gets driven accordingly