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| Hey guys, do you notice any noticeable differences between 3 and 4 blade props? I am trying to decide if I should get one. A run a Honda75. | |
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Posts: 96
Location: Eden Prairie, Mn. |
General - 3 fast , 4 lift
Yes !! but to help we need some critical info-to optimize performance.
We need to know what exact boat, model/layout, max engine rpm, mount hole 1/2/3/4, # of anglers, Kicker motor ?
TM bow/stern batt. location and how many.
Then we'll have you riding the 'pad'.
Mother
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Posts: 1335
Location: Chicago, Beverly | Hey Mother, would you mind helping me with prop selection? I could e-mail you the info when I get it all... Here is what I got off the top of my head: Its only a tuffy rampage 160 xt (1983 with sponsoned v hull) with a 1995 40hp evinrude, getting about 30mph(handheld gps) right now but no idea what rpms its turning. I want to say 12" pitch currently but would have to double check, I think I also have a 17" as a spare prop right now. No idea which hole its mounted on.. | |
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Posts: 96
Location: Eden Prairie, Mn. | Kevin,
I will assume a few things about your rig-
It's a tiller, the motor is in the lowest mounting hole, no power trim, Bow mnt. TM w/1 batt in bow area, starter batt. in stern and a 6-10gal portable gas tank in the stern also
You fish alone or with a partner a couple of tackle boxes, general gear and a cooler. A moderate load.
The engine operating range is 5000-5500 rpm, without a tach it's tough to gauge but, your probably around 5000-5200 RPM
raising the motor 2 holes would be the first thing to do, this will generally give you about a 200rpm gain.
Ck. top speed, it should give you about a 2-3mph gain just by increased RPM, spinning the prop faster in the motors
operating range. It may 'porpoise' - the bow lifting and dropping - caused by the props inability to hold the hull up out of the
water. You can minimize or eliminate this generally by moving some weight (gear/anchor) towards the rear of the boat.
Or if you have power trim this can be controlled by trimming IN or OUT, depending on load.
If not a better prop should fix it - I will assume that your existing prop is the original and maybe dinged up a bit or has been
refurbished, diminishing it's lifting/holding capabilties.
HUSTLER Props makes a nice affordable 'performance' Aluminum prop for small and mid-HP motors about $90.00 for hub
and prop with the 3 1/2 in. gear case. If you have the 4 1/2 in. gear case you may not need the hub kit and the prop is
only $60.00.
That being said, these props have increased stiffness, more 'cupping' - to provide bite and hull lift and better load carrying
capabilities and more precise blade machining. All of these factors lead to more speed, better hole shot, hull lifting and a
little increase in fuel economy.
Now we spent around $100.00 and go with the same 12 pitch prop and the same diameter and raise the motor 2 holes
- you go a little faster and your boat is quicker to plane and has better bite in turns and hvy. waves.
You can also go with a larger diameter prop-more hull lifting and load carrying- due to larger blade surface area with the same
pitch. You may to have lower the pitch to compensate for the increased load lowering your RPM.
I feel though that raising the motor will be enough to keep your RPM. I think you should have no problem with the
13 pitch 12 1/2 in. diameter set-up. If you have a Bass Pro shop catalog, you can find the prop/hub kit in it. Or call/ck. the
web site of Turning Point propellers - Hustler line - for more info.
Sorry for the long winded post. Hope it helps or I've completely confused you ?
Mother
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Posts: 1335
Location: Chicago, Beverly | Its a tiller, usually only run one battery in the back, if I run two then its two in back. 6 gallon tank in back.. It has power trim and tilt and my partner usually sits towards the front. 12" prop is brand new, the 17" came with the engine and has a couple small dings, nothing serious though. Both are OMC props. Gotta double check the pitch on both as I am going by memory. Trolling motor in front. I'll have to check and see what hole its mounted in and maybe look into a tach for the boat...The boat is down at the cottage so I won't be able to check for a week or so. Thanks.
Edited by kevin 3/21/2004 12:11 AM
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| A 1 " increase in prop size or pitch cuts about 200 rpm.
Example:
17 to 19 pitch prop will cut 400 rpm | |
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Posts: 1335
Location: Chicago, Beverly | Hey Mother, I got a little more info now. Prop on the boat right now is a 12 1/4X15, spare prop is 11 3/4X17. Going top to bottom with the mounting holes the motor is in the top hole. The trim adjustment rod(or whatever you call it) is in the hole closest to the transom and the trim tab/plate(?) right above the prop looks to be just slightly above the bottom of the V on the hull. Will the 17 pitch get me more speed or should I stay with the 15 pitch? Still haven't hooked it to a tach yet. Thanks. | |
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Posts: 5874
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| Prop on the boat right now is a 12 1/4X15, spare prop is 11 3/4X17. Going top to bottom with the mounting holes the motor is in the top hole. The trim adjustment rod(or whatever you call it) is in the hole closest to the transom and the trim tab/plate(?) right above the prop looks to be just slightly above the bottom of the V on the hull. Will the 17 pitch get me more speed or should I stay with the 15 pitch? Still haven't hooked it to a tach yet. Thanks.
Hi Kevin!!
I happen to run the 50 hp Johnson and will share a bit of what I know.
With your trim pin closest to the transom, your boat will plow quite a bit. I would bet you could move it out to the third hole away from the transom, which will get the boat out of the water quite a bit more. Your bow will rise a bit higher out of the water when you take off, but as soon as the boat planes out, it will come down. You will definitely gain some RPM's here....I'd venture to say somewhere in the region of 150 or so.
Also, when you move the motor up 2 holes, your stock props will do poorly on cornering. A switch to a better prop will be in order. I have not tried Hustler props, so I cannot comment there, but also check out solas props (www.solas.com) they have a line called the Alcup 3, which has a larger exhaust opening, creating more hp, and the possibility of going to a larger pitched prop.
I was able to go from a 12-1/4 x 15 stock aluminum to a 12 x 17 solas prop. I got better bite, and quite a bit faster...from about 31 to 35.
No doubt your rig can be made more efficient...you will like the changes if you make them.
Steve | |
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Posts: 1335
Location: Chicago, Beverly | Thanks Steve, I am already getting right about 30-31mph on the hand held gps. It does corner like crap if I go a little too tight in a turn. I may look into the Hustler or Sola props but I think I will try some of the stuff both you and Mother suggest with the old props and see what I am getting first since the 12X15 is brand new..haven't even run over the sand bar with it to remove the nice paint job on it yet..lol..
Edited by kevin 4/2/2004 11:46 PM
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Posts: 96
Location: Eden Prairie, Mn. | Kevin,
With the new info. provided we can go to work.
Manual trim bar- all the way in
Motor mounted at top hole- lowest mntg. position
New /undinged alum 12 1/4 x 15 prop
A tachometer will make testing extremely easy !!!
Lets start with the spare 17 pitch prop - the motor will never 'pull' the prop, not enough horse power. It's your
'get home' prop. No amount of tweaking will get you enough RPM to make the prop work.
The 15 pitch is your runner-
First - move the trim bar out one hole. Ck. speed, general handling and load carrying.
If faster and the boats handling is the same or improved - good.
Step 2 - Raise the motor one hole. Ck speed, handling and load carrying. pay attention to 'porpoising' lift/drop of bow.
Ck. speed, general handling and load carrying
Step 3 - If not move trim bar back in original position -
Did perf. drop or increase or remain the same ?
Step 4 - If it dropped, go back to the second trim position and raise the motor to the next hole (2nd hole)
Ck speed,handling and etc with the motor in the second hole up and trim bar out one hole from original position.
Step 5 - If worsened or same, move trim bar in to original position.
Ck speed, handling etc.
Step 6 - Move trim bar to best position.
Step 7 - Buy a performance mid-range HP SS prop or the a Hustler perf. Alum. prop and start testing all over.
You will gain top-end by systematically tweaking to find the 'sweet spot' but,
I feel that you may have rough water cavitation troubles and hi-speed turning issues with your alum. prop.
I had a '87 40HP Johnson on a 16' LUND Rebel Pike Special, It spun a almost the same prop you have and I raised the
the motor 2 holes and made a custom 'trim bar' for half way between the fisrt hole and the second hole. The trim
adjustment bar from one hole to the next was just too much for my boat/hull design. That was 8 years ago, before
I knew much and it taught me a lot about fundamental motor height, trim, props;load capacity, hull and balance.
I was able to get her to almost 35mph !!!! running with a light load.
Mother | |
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Posts: 1335
Location: Chicago, Beverly | Once again, Thank You. I was going to put the 17" on as soon as I was done messing around on the website here... Glad I checked in. I'll try the trim position for the weekend and see how it does. If I go to a new prop I think it will be the hustler due to the price I have seen on it.. A Stainless is too steep for me.. | |
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Posts: 1335
Location: Chicago, Beverly | Moved the trim rod out. got just barely a 32 out of the 15" prop..could keep a 31.8 pretty good. For the heck of it I threw the 17" prop on..33.5. Oly problem I had with it was I trimmed it out a little too far and the prop seemedto slip(cavitate??, like it got a air pocket), adjusted the trim quickly and it went away. The 15 got on plae way quicker, but the 17 seemed smoother despite the blades having some nicks..(nothing big, just bare aluminum on the edge of the blades and some burr's on the edges).. Never got what I thought to be the slipping on the 15.. Niether had any ride problems at speed. Moving the trim rod improved the overall ride of the boat with either prop. | |
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Posts: 96
Location: Eden Prairie, Mn. |
Kevin,
Good stuff !!
Where is everything at -
What hole is the engine mounted at ? Did you raise it ? How many holes ? Trim bar position ?
How light is that hull ? I figured you would never pull the 17 prop - Yes the boat would go but, to get that top-end.
Or did the boat take a whole lake to get to 33mph with you buck naked and running a one gallon gas can. 
How quickly could you get to plane and carry some load between the two props ?
The 17 felt smoother than the 15, do they both have the same thpe of hub ?
Boy, we need a tach so you can really find out whats happening. Where the RPM are at plane / top end / trim bar position.
Maybe the 17 is gonna be your 'fishin alone with a really light load' gotta run to the other side of the 50,000 acre lake prop.
Where speed is the only need.
Any major handling issues - Cavitation in waves, turning, 'blow out' at top speed.
The 'Hustler' prop will be a great choice.
Mother
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Posts: 364
Location: Kentucky | Mother, and other helpful folks:
Great info, and I hope you won't mind another consultation as I'm wanting to get the right stainless steel prop for my rig.
My current stats:
1994 Tuffy Renegade 1800C (deep-V fiberglass of course, I think the loaded weight estimate on the sticker is 1600 lbs.).
1994 Yamaha P150TRS (V6 two-stroke, power tilt/trim of course).
Wide Open Throttle rating 4500 - 5500.
current prop is Yamaha aluminum 13.5" dia., 23 pitch.
Wide Open RPM on my tach = 5400.
Current Top Speed is 52.
The current prop is in average condition, a few minor nicks and dings.
I experience no porpoising but prop blows out briefly during high speed turns.
I don't know what mounting hole the motor is in (I'll need to check later).
On the Renegade the batteries are in the rear (two trolling, one cranker), and the gas tank up front, I think it's 36 gallons.
I fish from 1 - 3 persons, with what I consider fairly heavy load (maybe 3 Lakewood Monster boxes and a cooler).
The current tach and speed above is with two 180 lb. guys, 3 tackle boxes, the cooler, etc.
I'm happy with the speed, but want to get the durability of the SS prop and preserve hole shot and get better cornering. A shop quoted me a 21 pitch 4 blade or a 21 pitch 3 blade, but that doesn't seem right to me.
Bonus question: my boat lists to port a bit, but seems worse when on plane. To compensate, I dorked with trim tab in all settings, installed a StingRay (dolphin) and distributed weight in the boat all to no effect. Lately I put about 80 lbs. of weight in the starboard rod locker and that works. It's not real bad, but just annoying. Doesn't seem related to amount of gas in the tank.
Thanks for any help. I appreciate it!  | |
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Posts: 1335
Location: Chicago, Beverly | WOW..lots of questions..lol.. Where is everything at -
What hole is the engine mounted at ?Engine still in the same place, didn't have the muscle to move it..or the engine jack.
Trim bar position ? Moved it out one to the middle
How light is that hull ? 800lbs without gear or motor.
How quickly could you get to plane and carry some load between the two props ? Load was about 200 lbs-250lbs lighter then usual, but with or without partner speeds always were extremely close. The 17 does not get on plane quite as quick, but it isn't slow either, with the 15 it just flattens out real quick and is to 30 a lot sooner, both hit 30 without moving the trim, fine tuning the trim bumps it up a bit to the top end speeds naturally. I need to get it out on Tippy(700+ acres, long shape to it) and really play with it there, I did this on Barbee(300 acres and just a bowl really) and run out of room quick.
The 17 felt smoother than the 15, do they both have the same type of hub ? Gonna have to check that. Its got me wondering too. Something was done to the exhaust to make it "breath" a little better and I never really noticed the difference before that was done. I am also gonna see if overtons or someone has some sort of small tach I could hook up and maybe hold in my free hand while checking this stuff out..
Any major handling issues - Cavitation in waves, turning, 'blow out' at top speed. No cavitation with either prop, but did get a little bit of a blowout with the 17 at top end. I may have trimmed it out too much as I didn't get that again but did get the 33+ again. I did not bother with any hard turning, maybe should have given that a shot with the new trim rod position, I'm pretty sure though that the 17 would blow out in the turn..but could be wrong. Like I said, I gonna see about getting some sort of tach, and get you some numbers, when I do that I will do some turning. I did run two batteries(normally only run one so maybe the weight difference of not having my brother and all of his gear wasn't too bad.. he's 190, tackle he brings couldn't be more then 25 I think.. Battery, maybe 40-50lbs??... Both props with the new trim position got up on plane quicker then before.
Thanks again... I just hope you don't charge too much for all this help.lol...
Edited by kevin 4/12/2004 4:43 PM
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Posts: 364
Location: Kentucky | ttt | |
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Posts: 96
Location: Eden Prairie, Mn. |
Sputter,
Sorry about the delay.
I think we can get some more MPH, increase holeshot, lower planing speeds and give you claws in turns and rough water.
First - raise the motor 2 holes, assuming it is mounted in the lowest position.
2nd- Contact the local Yamaha dealer and get a PRO-Series 23 pitch x 14 1/2 dia. SS prop and the 21 pitch, test them both
for speed, holeshot, turning, planing speed, load carrying( three buddies, beer n gear) Pick the one that meets your
needs.
If the RPM is slightly high on the 21- you can lower the motor one hole. Remeber its better to have a little too much
RPM than not enough, 100-200 RPM is OK , you can control it with trim/throttle.
These props are hi-Rake (hull lift) Progressive Pitch (holeshot/top end) Cupped ( lift/bite ) and Vented (holeshot)
This prop won't be cheap but, it will turn your boat into a monster compared to the old prop.(keep for spare)
Throw the Stingray/dolphin as far away from your boat as you can !!!!!!
The 'LIST' to port-left. Move batts /anchor and whaterver else to the starboard. Ckeck to see if the motor is mounted
on the centerline. Remove the 80 lb weight. Move bow storage heavy gear to the starboard side as well.
What side is the TM mounted on ? is it to port, offset a lot ? Trim tab - cut it flush, file smooooooth and bolt back on.
Heavy gear / cooler, behind you. Besides this , all you can do is add hull trim tabs but, that is a last resort and I
feel you should talk/ ride with a dealer before you get to that point .
Mother
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Any difference between 3 and 4 blade props?