SteveDavid, Tomcat......

I haven't seen this addressed here, so here it goes.

The blade profile, # of blades, dia have all been discussed, but what about finish? Mirror finish vs a dull, satin finish. It seems most 'over the counter' props have the mirror finish, but I don't notice this on the #6 drives and other exotics, and the hydros that I have noticed.
With a somewhat rough(sanded) hull bottom and non painted lower units claiming to have an edge, wouldn't it also pertain to the prop? What about different textures on the leading, following edges, front sides, backside of the blades, on the hubs or any combination of such? A mix and match if you will.
Are we giving up some speed for the polished look?

Thanks,
Jerry

Jerry,

Good question! It will be interesting to see what others have discovered.

I have not found a measurable difference between polished or satin finishes, be it Triple or Twin engine, single engine V bottom, (my former 18' DONZI) or our Unlimited Hydro. There are theories on which is best, but aside from real world testing, I don't know that any of the theories are backed by empirical evidence??

Take care,

Steve

polished should be better for fatigue related failure it will not give the blade a weak point to fracture from. We call that a tootsy roll groove. The polished finish will also help on in visual inspection with magnifux or by eye on seeing cracks. As for performance maybe jim or bob herring will see this and help. We tend to run their props because the are the best we can get. They are polished. I will call tomorrow to see what they have to say.
pat W

I don't mean to dilute the topic, but is there actually a concensus on the hull finish? Shiney (waxed) vs wet sanded???

Jerry, on advice from Bruce I may try my Hydromotive prop with only the backs of the blades satin. After I get baseline #'s and dialed in.
Eric

Steve, are you saying that you seen no gains when testing different props just for the finishes, or that the finish aspect has not been really a factor? Thanks

Brad, thou not absolutely sure if this was the cause, but last summer I lost 2 mph one weekend. Nothing I did, trim or whatever, would gain those 2 mph back that weekend. I just waxed the whole bottom the week before. Either just a coinsidence or some merit to it, I don't know. But I AIN't about to sand my bottom.


shifter, thanks. It will be very interesting to hear what you find out. I also understand the fatigue factor. Never thought of it though.

Jerry

Brad Perry,
Last summer I was talking to an owner of a 38 Special Baja. He was stumped at how he lost 5mph from the weekend before. He was asking what to look for with the engines. He said everything seemed to be running great. The boat was extremely clean. I asked if he ever waxed the bottom. He had waxed the bottom for the first time since he had bought the boat that week. I told him to strip the wax back off.
When I bought my Fountain I was warned not to wax the bottom. The wax helps the boat stick to the water and results in lost speed. I have heard that some race teams actually sand the bottoms.

I have never seen a difference in speed between a satin prop and a polished one. I’m only running in the low 70’s so it might not make as big of a difference.

Dan

This year I plan on sanding the wetted surface of my hull , using #400 paper and a block sander. I will also sharpen any edges. I was told this trick from a friend of mine that used to race F-4 (now it's , take a breath "super cat light outboard" whew !) they did this to there boat, it is supposeded to aireate (sp) the water that contacts the hull.
Also never wax the wetted surface of the hull.


When I had my prop labbed I opted for the satin finish.