Slow boat, do I have a problem

[Neil2]

The OP doesn't seem to suggest that the problem is confined to the autumn. His description seems more like cavitation to me. As the boat builds up speed and the water profile around the hull changes, air is being sucked down into the prop. The prop is then thrashing lots of very elastic air and throwing it out the back. Stopping or going into reverse breaks the cycle for a while before it returns again.

 

Add some ballast to the stern, or take some out of the bow. A simple test would be to put a big plastic dustbin the back deck and fill it with water.

You're talking about ventilation. It could be the problem I suppose but the boat would have to be seriously out of trim or possibly the seal on the weed hatch isn't 100%?

[Mike Todd]

You're talking about ventilation. It could be the problem I suppose but the boat would have to be seriously out of trim or possibly the seal on the weed hatch isn't 100%?

Reminded of our early boating days when there were still a few working boats around. It was sometimes reported that their steerers would enjoy reacting to an uninvited over-taker by looking straight ahead whilst covertly gradually winding up the throttle so that the overtaker suddenly found themselves stuck alongside not able to maintain their fatser speed as the heavier/larger boats thrust effectively pushed them back!

 

Beginners should be told that overtaking ought only be attempted on invitation (which should not be unreasonably withheld) The boat in front usually has a better view of whether the overtake is safe and if there is room before the next blind bend. The operation takes much longer than many boaters realise.

[Sea Dog]

The OP doesn't seem to suggest that the problem is confined to the autumn. His description seems more like cavitation to me. As the boat builds up speed and the water profile around the hull changes, air is being sucked down into the prop. The prop is then thrashing lots of very elastic air and throwing it out the back. Stopping or going into reverse breaks the cycle for a while before it returns again.

 

Add some ballast to the stern, or take some out of the bow. A simple test would be to put a big plastic dustbin the back deck and fill it with water.

 

You missed an update....

 

, it was indeed end of summer and there were plenty of leaves around.

 

 

You're talking about ventilation. It could be the problem I suppose but the boat would have to be seriously out of trim or possibly the seal on the weed hatch isn't 100%?

 

Neil's right, that would be ventilation, and it would be a bad thing all round to have a poorly sealed weed hatch, so check that just in case. T'other quick check would be that your uxter plate is an inch and a half or so below the surface as if that's high you can draw air in and ventilate the prop. It would be a bit strange if she was suddenly sitting high at the back though, so once you've had a glance you can go back to clearing those leaves!

 

Oh, and you go as just slow as you like in Dignity. I'm happy to be waved through ...... or to wave you through if you're in a hurry one day!