Guess not all prop shops are created equal

[kennyk]

Hi All, just thought I'd share. I have a Stainless Ballistic 12-3/8 x 15 that I wanted to re-pitch to 13" to bring up my rpm so I called my local prop shop and they told me they would have to charge me for the price of reconditioning a SST prop since they would have to heat it and change the bushing hub also. Basically told me it wouldn't be worth it since it would cost $189. This is a brand new prop I bought off of Ebay, well pretty much stole it for $73 total. Next I went online and found a shop that told me they could do it for $40 and $8.50 shipping. They said they did one similar just a couple of weeks ago. Most of the time they don't have to heat them but he said if they do it still wouldn't be so hot as to ruin the hub. From most of my reading I only thought a stainless could be changed 1" but they said 2" was ok. They must also have a better pitch block press system than my local shop. Anyway, it seems that it pays to shop around. Ken

 

[achris]

Re: Guess not all prop shops are created equal

Sounds like SOP to me... I've lost count of how many times I've been told something can't be done, only to either do it myself or find someone else who can do it. Usually the former.

Chris.....

 

[Frank Acampora]

Re: Guess not all prop shops are created equal

Yeah! And I sent out a prop to have a bent blade and wrinkled leading edges repaired. My favorite SS prop. The Bast---- re curved the leading edge instead of adding weld and repairing it, changed the blade shape, and reduced the blade area. Last time I send anything to that shop. Threw a fit when I got it back. Worst 90 bucks I ever spent.

 

[Dhadley]

Re: Guess not all prop shops are created equal

We do everything possible to try and gain rpm with set up rather than go to less pitch. For max efficiency you'll be much better off with a 13" prop rather than lowering pitch on the 15. They're going to reduce bite or efficiency to let the prop slip more. That's the easy way to gain rpm but you'll most likely lose overall efficiency.

The only true way to create a 13" prop from a 15" is to reposition the blades.

You must be running a fairly small motor on a relatively large boat. What'cha got?

 

[kennyk]

Re: Guess not all prop shops are created equal

Hi, not a large boat, it's a 14' McKee Craft although it is most likely waterlogged some, and a '84 50hp Johnson. I was running 28 gps mph and 4800 rpm with a stock 12-1/2 x 15 P al prop. At the time I was looking for a spare I only had a Seloc manual and it had WOT at 4500. So I won a 15P brand new ballistic prop on Ebay at a great deal for $73 and I was happy. Until my OEM Service manual came and I saw they had my WOT at 4500 to 5500. So, I looked into dropping the 15P Ballistic to 13P to pick up the extra 400 or so RPM. For $50 and some change I was thinking it might be worth it. Not sure if I would pick up any top end MPH but my hole and mid should improve. Oh, that 28 mph was just me and light load so if I take a buddy or two I would be lugging even more. Thoughts? Ken

 

[kennyk]

Re: Guess not all prop shops are created equal

Dhadley, I didn't know I might be changing the integrity of the prop by de-pitching 2" I just figured it would act like a 13P prop. A true 13P on this boat should give better hole and mid and allow me to run near 5500 Wot. If it won't do this for me I'll sell the Ballsitic or trade if there is any sites that will do that and buy a new 13P Aluminum, I really don't need the "bling" with the looks of my boat. Lt me know what you would do as it is packaged and ready to ship out tomorrow. Thanks, Ken

 

[Dhadley]

Re: Guess not all prop shops are created equal

Have you tried raising the motor? Where is the anti-ventalation plate in relation to the bottom when parallel?

 

[kennyk]

Re: Guess not all prop shops are created equal

Cav plate is even with bot, haven't tried raising it. I have a stingray on the motor so my hole and mid is very acceptablen with the 15p alum. I was just trying to get some more rpm. Figured pitch was the easiest. Do you thing raising the motor on such a low hp motor and fairly slow boat would show any improvement?

 

[Dhadley]

Re: Guess not all prop shops are created equal

With the motor that low it would be unusual for the fin to be helping. Most times with the motor that low we see the fin hurting efficiency.

Raising the motor and using the 15 aluminum may create some venting problems. Once you reach that point the fin may actually help. Maybe, maybe not. The SR isn't that great of a design.

However, raising the motor with the ss will most likely improve efficiency. I'm not exactly a fan of Ballistic props but they work well on some rigs. Running the ss at the same height as an aluminum prop is the most common mistake made in setting up.

It would be my suggestion to try both the alum and the ss prop at a higher X dimension without the fin. Once you reach a point of venting, then put the fin on. Go up in small steps, keep good notes. Go by solid data, not guesswork.

 

[steelespike]

Re: Guess not all prop shops are created equal

Cav plate is even with bot, haven't tried raising it. I have a stingray on the motor so my hole and mid is very acceptablen with the 15p alum. I was just trying to get some more rpm. Figured pitch was the easiest. Do you thing raising the motor on such a low hp motor and fairly slow boat would show any improvement?

There is no doubt raising the motor could improve speed and rpm.
Ive seen tests on 40 hp setups give almost 3 mph simply by raising the motor.It all depends on your present setup.28 seems pretty slow to me.
I would think 35 would be possible.Unless the boat has problerms water or a hook comes to mind.

 

[kennyk]

Re: Guess not all prop shops are created equal

dhadley and steelespike, thank you for your advise. I think I will exercise a little patience and hold on to the 15P Ballistic and do some testing on the motor height and stingray when temps warm up here in Delaware in mid March. I did buy a very used 13P alum. prop on ebay yesterday cheaply so that will give me some more data to look at. The previous motor was a 40hp Merc that came with a 15P al prop and the rpms were way down and the performance was terrible. I ended up running a 12P al for my rig to feel like I had any power. I was only running 23 mph with that set up so increasing the hp by 10 gave me another 5 mph with the 50hp. The boat is a McKee craft with the pressure foam insulation and pretty much any hole I drill in the boat along the transom will respond with dripping water. Also had to replace the bow ring? last year and thought I had to pull a plate to get to it and when I did all the foam in the front there was also waterlogged. I really should weigh the boat and see how it compares to original. So no doubt I have extra weight issues. When you're poor you have to make the best of it cause I love boating and being on the water. Ken