[m&mmariah]

Hi Mike;

Do you know of any on-line data that actually lists prop performance specs? I'm thinking of something like MerCrusier having published data as in: "Alpha 4 prop 14 x 20 max thrust is 225 lbs @ 4750 rpm" or "Black Max 14.25 x 19 prop max thrust is 198 lbs @ 4680 rpm." That would make is so much easier to compare props and make an educated selection, at least within the same brand. A performance curve would be even more helpful, like those published in car magazines that list hp & torque curves for an engine at various rpms. If you can run a car on a dyno and get such info, why can't you hook up a boat to a static tow rope, run it up to various rpm, then measure the pulling power/prop thrust? Maybe there are just too many real-world design variables.

Mark

[mikeyt]

I'm not aware of any such data source that could be used to compare different props. I suspect its because the props can provide different results on similar boats which means there are just too many variables to consider. I'm sure that Mercury or any of the other prop builders have tested their props & can provide such information although it will likely be done on a common platform to get consistency in the results. Unfortunately that common platform may not be suitable for us...

I've seen other boating forums where they have 1 or 2 guys that actually test different props & provide results but again, if they test the prop on something like say a Boston Whaler, the results will be useless for us.

[al levy]

most boats are sent out with the average prop recommended from the mfg. however this does not consider what you want to use the boat for, people in the boat, fuel and weather conditions. a good prop man should be able to help you and in many instances give you different props to try.