outboard prop

[justryd]

I have a 29' twin keel sailboat with an outboard well. I'd like a little more speed it runs only 2-3 knots now its a 1995 9.9 is there any thing I can do with the prop to get a little more speed ( the use of the word speed seems silly) id like to get another couple mls/hr. out of her. any suggestions.

[ath]

A 9.9 HP should push a 29' along much quicker than 2 - 3 knts providing the bottom is clean etc. I have a 25' and the 6hp pushes the boat close to hull speed. Displacement? How much does it weigh? How deep does the prop go? The angle of the prop matters too. This can be adjusted with a pin on the shaft. The prop should be driving the boat forward and not angled up or down. Experiment. You may need a longer shaft. Is the prop deep enough in the water? You can extend the shaft on most outboards with an extension. You should have a motor that pushes the boat close to hull speed in case you get into heavy seas etc and need it. Have you checked the engine? Is it running at full rpms? Is there a govenor on the throttle stopping it from opening up? Finally, do you have the right prop? I've seen the wrong prop sometimes. Or, take the prop off and make sure the sheer pin is good still and that the prop is engaging.

[justryd]

the boat is out of the water right now were looking at the shaft lenth i belive its a long shaft but im not 100% its a twin keel i think some of the problem. the displacement is around 6500. thanks for your input

[bolov]

I have a 21ft twin keeler and can reach 95% hull speed with 4hp. I would have thought 9.9hp would easily give you 5 kts. Is the prop too coarse ?