quick pitch question

This topic has 8 replies, 5 voices, and was last updated 15 years, 9 months ago by Alabass.

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August 31, 2010 at 7:23 pm #384578

newbcbowner
Participant

Hello all.I currently running the wrong prop on my boat. Its the Spinelli Bros 4 blade. I believe it to be a 26 pitch. It has no designation stamped on it. Im also running a 95 Mariner 200 h.p.Anyway at WOT, Im running about 5750 rpms and the handheld gps says that Im running 62 mph.Now, if I go to a lower pitch (25) wouldnt the prop be rotating faster with less forward thrust?Im new at this and need some assistance. Im sure Im totally off base here.Thanks all, Ben.

August 31, 2010 at 8:17 pm #384581

Bass Cat Boats
Keymaster

What boat ?And what type load do you carry ?The smaller pitch will turn more rpms, but theres no telling what pitch you are running now. I would probably try a 25P Fury, or Tempest to see where they run, and go from there, on that year engine you may have to go with a 24 p Fury.Go here and it will give you a better idea of where u should be.http://www.rbbi.com/folders/prop/propcalc.htmLast edited by dbasketman on August 31st, 2010, 8:23 pm, edited 2 times in total.

August 31, 2010 at 9:09 pm #384584

Bass Cat Boats
Keymaster

Try a 24 Fury on your rig, as you know BCB does not prefer a Spinelli on any of their bass applications. There are a couple of boats up in the northeast that have Spinellis in the mid 90s year models. They seem to be sold around and the same question just keeps coming up, though no one ever changes the Spinelli. It is one of the worst performing propellers on a BCB hull of this stature. Please find another wheel to run on your rig and see how it performs.

August 31, 2010 at 9:24 pm #384587

newbcbowner
Participant

Im trying, Im trying….!!!!dbasketman, Its a 95 Pantera II. I usually carry, what I would consider a very light load. (Usually the port side gas 3/4 full (Starboard side 1/4), five rods and enough tackle for a big bag.)This IS my quest to change props.I wouldnt think I would need anymore rpms than the 5750 that Im running now. (But I dont know that for sure)Shouldnt this hull run faster than 62 mph? If so, roughly what is the difference I should expect. ( A little one like 3 mphs??….or like 7-8 mph?)I was directed towards a 25 pitch Laser II, a 25 pitch Trophy and a 25 pitch Tempest by BCB when I called parts.I guess Ill include a 24 Fury to that list as well….?????Thanks again.

August 31, 2010 at 9:27 pm #384591

NacCat
Participant

Something doesnt sound right. I looked in your accont and saw that in another post you have a 95 Pantera 2. If you have a 26 p prop turning 5750 rpm with a 95 200 Mariner then you would have most likely a 1.87 gear ratio lower unit which means you would have 18 % slip. That seems way too much to me. Im not familiar with a Spinelli prop but it sounds like to me you have a problem with the prop, a spun hub, bent blade or you are lifted way too high on the jackplate and you are not lifting the boat at all. I have a 1994 Pantera 2 with a 94 Mariner 150 EFI and with a Yamaha 23M I am running 5870 with two people and running 62.4 mph on the GPS. I would think you would be flying with a 26, if you can turn it and it lifts the boat. I agree with dbasketman on the prop recommendations.Mike

August 31, 2010 at 10:07 pm #384594

gchagler
Participant

newbcbowner, I have an 08 PII with a 200 opti on it, I know there is a big difference in the boat/motor but I also have a spinelli bros 26 4 blade and it did just as well on top end as my 26 trophy but it blew out when getting out of the hole. it would push the boat 72 mph before it got in the rev limiter at 5750. I dont know if that helps you but I thought it might.

August 31, 2010 at 10:09 pm #384597

gchagler
Participant

Oh and the pitch 26 is stamped in the inside of the prop on the end closest to the front of the boat. You must remove the prop to see it.

September 1, 2010 at 12:59 am #384600

newbcbowner
Participant

All of this is good info.I trying to come to the SEBCOG and have some of you knowledgeable peeps help me measure my jackplate height.After this I think I can start narrowing the culprit down. (One or both problems)Any other suggestions are welcomed.Thanks, Ben.

September 1, 2010 at 1:24 am #384603

Alabass
Participant

I have a 95 PII w/200 Mariner also. Im running a 25p Trophy and can get about 64 – 65mph in cooler weather with a light load. I think I was turning it about 5750 – 5800 rpms at WOT.
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