Quote:
Originally Posted by Dave R
Reading this has me thinking that you may not have a stainless steel prop since you refer to the DP setup as "stainless", and your prop as "steel" as though they were two different things. If your prop is painted it's likely aluminum and upgrading to stainless steel would make a huge difference, especially if you have a V8 engine. V8s make too much torque for aluminum props, IMO, and flex the blades under load. This makes the boat feel "mushy" while accelerating as the blades flatten out and lose grip. Stainless steel blades have substantially less flex even though they are typically a lot thinner than aluminum blades. Thinner blades require less power to spin so they are also more efficient.
If you currently have a 3 blade aluminum prop, a 4 blade stainless steel prop could really make you smile. It's a nice compromise between top speed (which will be roughly equal to the aluminum 3 blade, but not as fast as a stainless 3 blade) and acceleration (which would be better than either 3 blade prop) assuming it's pitched correctly.
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I was just going to mention the same thing.....
There are all sorts of prop designs out there, pitches, number of blades, shapes and sizes. Finding the right balance will have a noticeable change in overall performance.
Without a doubt with a big heavy boat with a single stern drive you'll likely not be able to achieve the same performance as a duo-prop (two props counter rotating) however even just moving from a 3 to a 4+ blade prop will give you much more bite in the water. Just from my own experience of using a aluminum vs stainless prop I did not see any notable difference in performance at least with a 190HP Merc w/Alpha 1 stern drive. You may be able to find suitable performance in playing with different props and specifically pitches vs diameter. Just remember a few things as far as that goes.... there is a happy medium you need to achieve.
Pitches are measured differently depending on the number of blades the prop has. The lower the pitch the better the hole shot, but you go to low you may end up with cavitation problems as well as be operating the engine at an RPM outside recommended max RPM values at WOT. On the opposite side of the spectrum, if you go to high, it'll take much longer to get up on plane especially with a fully loaded boat, your top end speed at WOT may be faster at a lower RPM thus providing better "gas mileage".
I would suggest with a boat that size try a 4 or even 5 blade prop that is equivalent pitch wise to the 3 blade you have now and see how that works. After that try going up and down in pitch to see what difference that makes until you are satisfied with the performance. Most marinas are pretty good in allowing you to try various props so long as you bring them back in as new condition. Do bear in mind that the age of your stern drive may be a factor in what options you have to choose from.