Turbo Ultima vs Stiletto Bay Pro III

[Dhadley]

Re: Turbo Ultima vs Stiletto Bay Pro III

Experience shows us that if you can run 100% positive trim without venting and slowing down at wot then the X dimension can, most likely, be increased. Yes, there is a fine line between too high and not high enough to get the max out of a given prop. Naturally the intended use giudelines come into play as always.

In this case we're lucky to be comparing a 3 blade and a 4 blade of comparable blade design. Sometimes we're not that lucky.

We see a lot of folks trying to compare a 3 blade and a 4 blade at the same X dimension even if they are similar in design. In that case the 4 blade usually comes out looking bad or at least not as good as it could be. That was pretty common when 4 blade props became popular and why most folks thought you gave up top speed in every case going from 3 to 4. Today we know that's not always the case.

 

[JARB]

Re: Turbo Ultima vs Stiletto Bay Pro III

Well.. it is time for an update of this thread and my Turbo Ultima 14,25 x 17". During the winter I raised the motor to the highest postion. The AV-plate is now about 2 1/4 inch above the bottom. I havent been able to do any precise testing but I gained about 200 rpm and 1 mph by raising the engine. WOT is now 5700 rpm and top speed is about 46 mph. I was hoping to gain more speed and rpm by raising the engine but maybe the Ultima has too much surface area for my small yamaha F150? At this height the prop has lost some of its great bite. I now can loose grip in heavy following seas and in sharp turns at high trim angles. When the engine was 1 1/2 inch lower it never lost grip.. All in all I am very satisfied with the Ultima, especialy at cruising speed where it now gives even better mileage than before. But I think maybe the boat and engine would benefit from a smaller diameter and less aggressive 4-blade than the Ultima. What do You think about an 14 x 18" 2+2TH Dhadley?

I also did a quick test of the Turbo 1 14,25 x 19" that was performing very well when the engine was only 3/4" above the bottom. Sadly the T1 performed very poor at this engine height. I couldnt get any exact performance numbers due to wheather conditions but the prop ventilated very very easily. This was a bit confusing for me since I have been running a Stiletto Advantage at this height on my former boat with excellent performance. The only main difference is that my current boat is more front heavy than the former one.

I have been thinking a bit about replacing the Turbo 1 with a 19" Mercury Tempest although the Tempest at 14 5/8" diameter is over the 14 1/4" limit that is recommended for the F150. Hopefully the tempest will provide enough grip at this height, what do You think Dhadley? I really want to have a working 3-blade too, hopefully passing 50 mph Another option is to lower the engine to 1 1/2" above the bottom and see how the T1 performs...

Any inputs are appreciated!