The pivot point of a boat seems to be a topic of much interest and there is a lot of confusion surrounding what it is, where it is and how it affects boat docking.
Some of the boating forums we visited have many self-proclaimed experts challenging and arguing with each other about who has the correct answer and why it is important. One "expert" insisted that physics was his area of expertise and insisted that the pivot point was between the propellers while other "experts" and boaters challenged him and argued with him.
Simply put, the pivot point is......
the centre of the turning circle, or the point around which the boat pivots.
If the pivot point was at the back of the boat between the propellers, just like a kid spinning on the back two wheels of his skateboard, then the bow would swing around and the transom would remain at that pivot point (i.e. stationary) when pivoting.
In my 60 years of boating, I've never seen a boat perform this stunt!
If just the motors were pivoting with no boat attached, the pivot point would be between the propellers. But, in the real world on the water, there's a hull ahead of the propellers and there's friction against the boat—both above and below the waterline.
The friction below the waterline is caused by the hull, with or without a keel, dragging against the sideways motion of the boat when pivoting. The friction above the waterline is caused by the wind on the superstructure and vertical canvas panels as the boat pivots—called windage.
This drag (above and below the waterline) moves the pivot point from the theoretical location between the propellers to a point that is approximately one half to one third of the boat length ahead of the transom. It varies because all boats are different, all boat hulls are different, all boat superstructures are different and sea and weather conditions vary.
Then the Captain can move the pivot fore or aft depending on what he does with the wheel, shift(s) and throttle(s). Depending on the drive system, the action of the Captain varies.
For most recreational boaters, trying to understand the theory and apply it to their boats becomes confusing and overwhelming adding to the stress of docking.
The good news is that when docking, you don't have to know all the theory and technical jargon, you just have to know how to control your boat and how to control the position of the pivot point to work for you instead of against you.
Doug Dawson's docking lessons, for each different drive system, teach you
- how to choose the most advantageous pivot point for your docking scenerio.
- How to change the location of your pivot point to be best for your particular docking situation
- What to do with the wheel, shift(s) and throttle(s) in combination with your chosen pivot point to take the worry, stress and fear out of docking.
Doug Dawson's Power Boat Docking Procedure
all types of power boats and all drive systems.
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