Is the new SS prop a waste of my money?

Expert? No.<br /><br />Assuming that the black max is a 3 blade stainless prop as the ballistic is...<br /><br />You will pick up some RPM's, maybe putting you above the 4400 mark. Maybe not. <br /><br />You should get a much improved holeshot, even without the tabs, and should be awesome with them. Ballistic's pull. <br /><br />If you can't return it, make the best of it and try it. You might like it. <br /><br />Let us know what happens.

Is the new SS prop a waste of my money?

In another thread here on this forum I was advised that trim tabs would be the solution to my problem, i.e. getting a better ride and quicker planing at lower speeds. I've now ordered a set of Smart Tabs and look forward to trying them out next week.<br /><br />Trouble is, I had already been talked into replacing the standard prop that came with the boat (23" Black Max) with a 21" Ballistic. This can't be undone as the prop is already underway from the US to me here in Norway.<br /><br />NautiJohn said that this prop change probably wouldn't do me much good, and that it might negatively affect both top end speed and fuel consumption. My hope was that it would also give me a better accelleration, hole shot, and better ability to trim the drive without losing the grip.<br /><br />Any views on this? Am I better off trying to sell my new-in-the-box Ballistic, or should I put it on, enjoy the ride, and keep the Black Max as a spare? What can I realistically expect in terms of performance differences between these two?<br /><br />By the way, I have a 21 foot daycruiser with a deep V-hull, beam of 240 cm, dry weight of about 2650 lbs. The engine is a 120 hp Mercruiser turbodiesel with a recommended max RPM of about 4400 rpm, and current WOT of about 4200. It has an Alpha drive, doing up to 36 knots, and planing at around 15 knots (and soon, hopefully at less).<br /><br />Any expert advise?

Re: Is the new SS prop a waste of my money?

Thank you! I was hoping to hear something like that.<br /><br />The Black Max is a three-blade aluminum prop, and the Ballistic is a three-blade stainless steel one.<br /><br />They both have about 14" diameter, and the Ballistic is one step lower in pitch (21" instead of 23").<br /><br />The engine has some kind of RPM-protection mechanism that doesn't allow it to go above 4500. Not that we ever like to go at full speed, anyway - the kids aren't big enough to enjoy that yet.<br /><br />Do the rest of you agree with Stiff Nibbles' point of view? Any comments would be appreciated.

Re: Is the new SS prop a waste of my money?

Just want to add that you may see little or no difference in RPM at all, since the 23P is aluminum. You should be just fine.

Re: Is the new SS prop a waste of my money?

Holeshot will be better. You might lose a knot or two. Ballistics are okay props. A better choice might be a High Five, but they're about double the price. <br /><br />High Fives seem to work well on large boats with small motors. But your biggest improvement will be with those trim tabs. Those can help plane a boat at slower speeds because they change the dynamics of the hull. A prop is just a prop.<br /><br />Just to throw some more confusion at you, there is a 4-blade aluminum Alpha prop that produces Stern lift. They are available in 16", 18", and 20" pitches, so that might not be viable on your boat given the RPMs you're getting with a 23".

Re: Is the new SS prop a waste of my money?

Thank you both for your comments. I think it is great to be able to get qualified input from someone who has no commercial motive in offering it, and I wish I had known about this forum before.<br /><br />Glad to hear that both the trim tabs and the propeller probably will contribute as I had hoped. I'll post back here in a few weeks when the boat is on the water and I've had a chance to try things out.<br /><br />Thanks again!

Re: Is the new SS prop a waste of my money?

Stevens;<br />I must not have made my self understood. Sorry! Going down in pitch will give you the same effect as going down to second gear in a car. You will experience better acceleration, however, you will turn the engine more for every mile and use more fuel. What I have always said is that you should first make the hull perform at it's best then prop. No sence trying to prop to the best performance if your anchor is still in the water.<br /><br />The Smart Tabs in combination with a lower pitch prop may push the RPMs too high (at WOT).<br /><br />Let us know what you find out, but don't change two thing at a time.

Re: Is the new SS prop a waste of my money?

As stiff n. stated the stainless prop probably has more cup than the aluninum and he may not gain any rpm. Also, more cupping can be easily added to effectively increase pitch and bite on the water.

Re: Is the new SS prop a waste of my money?

I'm going to throw a wrench in here....the Ballistic will not hold as much trim as many other stainless props, and there are VERY FEW prop shops that will mess with them.<br />The Ballistic IS a hard-pulling prop, but with basically no increase in speed for robbing the RPM they do.<br />With Smart-tabs, it may prove more effective.<br />As John stated, it's best to maximize what you have before adding parts...<br />Good luck however you choose to go.

Re: Is the new SS prop a waste of my money?

Thanks again, guys, for your kind advise. I'll let you know how this works out.

Re: Is the new SS prop a waste of my money?

OK, here's the result from the first trials today.<br /><br />I added the Smart Tabs first, then swapped propellers. Went out for a few hours, a little choppy a bit out, but also some almost calm waters further in.<br /> <br />Smart Tabs first; wow! I'll comment on that in a separate thread. Suffice to say here, they did everything they promised to do! <br /> <br />No loss of top speed, but no gain either. The GPS remained at 36 knots at 4300 rpm.<br /> <br />Adding the Ballistic propeller (going from the 23" Black Max alu prop to the 21" steel Ballistic, both 3 blade), gave a noticably better accelleration from zero, a slightly better ability to trim the drive further out at high speeds, and a better grip in the chop and tight turns.<br /><br />However, I also lost 1-2 knots of top speed, maxing out at 34-35 knots at 4500 rpm (which is the highest the engine will go before the rev limiter kicks in), on relatively smooth water.<br /> <br />This should indicate that the original propeller had a slip of 23% (with and without tabs), and the new one a slip of 22%. I had expected a larger difference, i.e. a better bite to show up in the numbers.<br /> <br />All in all, the Smart Tabs were well worth the money, whereas the new propeller is more of a luxury; no great added benefit, but it did directionally help. Since I can't return it, I'll keep it and enjoy the improved hole-shot.<br /> <br />Would I buy the same again? The Smart Tabs, absolutely. The propeller, probably not.<br /><br />Thanks guys, for all your kind and valuable input.

Re: Is the new SS prop a waste of my money?

See if you can get a prop shop to add some more cup to the ss prop. It will add to the bite as well as the efficiency and should lower the rpms and increase speed. I do my own cupping with a hammer and trailer hitch ball with good success, but it may not be the best method for you.

Re: Is the new SS prop a waste of my money?

No, that method is not for me!<br /><br />Anyway, I think I'll have to leave things as they are. I've already spent enough on this project, and I don't think any reputable local prop shop would touch this for less than $150 or more. You see, any good mechanic is paid at least $50 per hour over here.<br /><br />At least I now have a propeller on the boat that works well, and another good one as a spare.<br /><br />Wishing you all a nice summer!

Re: Is the new SS prop a waste of my money?

Stevens, if you ever get the chance, try another wheel such as a Turbo of simular pitch, Or a stiletto...You will see a significant gain in all areas.

Re: Is the new SS prop a waste of my money?

Sorry, guys, I just now realize that the prop slip calculator I was using was based on MPH not knots. (www.go-fast.com/Prop_Slip_Calculator.htm)<br /><br />When I input the right numbers, it turns out my old aluminium Black Max 23" had a slip of about 13%, and the new steel Ballistic 21" has a slip of 8%.<br /><br />That sounds about right, doesn't it?<br /><br />And, am I right in thinking that 8% is a pretty good number for my type of boat?