Minimum boat speed under power

[Montanan]

My minimum "marina speed" when under power is zero as it is easy enough to just throttle in reverse to stop quickly and then bump for short burst in forward to make way.

Now on those times when I have had to sail into the marina due to the engine not working, the SOG depends on how strong the wind was blowing, what direction the wind was from and how many and how much sail I was deploying when maneuvering through the channels to our slip. It is very helpful to enter the slip with a head wind so as to stall the boat in iron or backwinding of a sail.
Much more difficult when entering the slip while running as one has to utilize dock lines to slow before bumping the bow. Quite entertaining to arrive at the dock in a crowded marina while under sail power.

[nortonscove]

Irrelevant where I am because it's so rarely calm. Keeping power on is pretty much essential but I'm thinking mine would be less than 2 knots.

[gonesail]

if you need to go slower .. alternate between neutral and in gear.

[GreenWave]

Originally Posted by Shrew

If you need to go slower than your idle speed, periodically bump it into neutral, then back into gear. Repeat periodically to maintain your desired speed. I usually only do that in close quarters (mooring fields and tight anchorages) and when docking.

Slower than 2 kts and I start to loose steerage. At that speed and slower, it requires exaggerated rudder input for small changes in course.

For me this "minimum speed for steerage" is what is more important. I need at least 2 knots for this, especially with any crosswind. I get annoyed sometimes at our one bridge channel when boats decide to go to neutral right in the middle of the channel to gawk etc.

[ohdrinkboy]

Depends on which of my small boats I'm driving. Both I'm in and out of gear to have the correct speed. On the sailboat, it is responsive down to drifting. The power boat I have to use the motor more because there is no rudder. If I am going too fast, I do use reverse as a brake.

I go as slow as I can possibly go and maintain steerage.

[David Mathis]

Our 43’ Portofino has twin 420 hp caterpillars. With the throttles all the way back it idles at 5.3 knots. With only one engine engaged, it handles poorly but still moves along at over four knots.

[Pizzazz]

On a 31 ft Hunter with a 16 hp Yanmar minimum speed was 2.6 knots. On a 48 ft Riva Superamerica, min speed in idle is 5.8-6.0 knots. Larger engines on powerboats typically have hydraulic gearboxes and electronic shift control which makes shifting in and out of gear much easier than on mechanical gearboxes. Still, it is not easy in tight spaces with a 6 knot min speed.

[GrowleyMonster]

I could slow the prop on my electric boat to about 20 RPM which gave me a speed of a small fraction of a knot, with no bumping in and out of gear. It was really nice for easing into a slip. This was especially nice for backing into the slip. I could get some sternway on and then slow the prop way down, and steer fairly well going astern. Try that with a diesel.

My current boat has a diesel and at idle I am doing a bit less than 3kts in slick calm water.

[Tanqueray]

On my 32-foot O’Day 322, with a Yanmar diesel, I come into the marina at idle, and between 2.5 -3.0 knots. As I approach my fairway and slip, I will slip the transmission into neutral, and re-engage if needed. If the wind is to my back, and I am coming in hot, slip her into reverse.

Remember…don’t approach the dock faster than you are willing to hit it

Greg

[IRENE]

3 knots on the main engine, much slower on the wing. 3 knots is bare steerageway. 55,000 lbs.