Propeller upgrade

[Fallguy]

Hi all,

Still being new to all this I wonder if I can call upon you to help me. I've got a new Honda 5HP outboard that has served me well this season, I'm using it to power a 19ft sailboat (when not sailing of course ). I has been suggested that changing the propeller on an outboard may help her travel more effectively and go astern better. Can anyone advise me on this and where I might be able to get a propeller to do the job?

Thanks in advance

 

[VicS]

A sailing boat , or any displcement type of boat usually is best with a low pitch prop, perhaps with a larger than standard diameter and or blade area.

I can see there are several props available for your engine but I do not have the specs for them. ( the standard one is I believe 3 blades 200mm x 190mm)

The downside of fitting a low pitch prop of course is that for any given boat speed the engine revs are higher!

Lack of thrust astern is usually the result of exhaust gas being drawn into the prop. Commonly small outboards have the exhaust arranged to exit behind the prop. This means that the gases are drawn into the pro when going astern. As far as I can see this applies to your engine

"Sail" versions may have the exhaust outlet positioned so that this does not happen.
In the outboard pictured below the exhaust outlet is the square hole between the twin cavitation plates. What appears to be an exhaust outlet behind the prop, and is indeed just that in the standard model, is plugged.

If you need to improve the thrust ahead a change of prop may help but solving the problem of lack of thrust astern may not be so simple if the reason for it being poor is as above

. 6hp Evinrude Yachtwin on a 19 footer