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gtsmpuc
06-07-2001, 10:29 AM
I was wondering if anybody out there had one of these hulls so I could talk prop selection with tehm. I just purchsed the boat, a '94, its a full tunnel w/ a '95 motor. The motor has 11.5" of set back, sitting about 2" below the pad. The prop that came with the boat is a Merc High five 25p. It pulls like a bat out of hell all tha way to 6,200 RPM (rev limiter), where I'm doing in the neighbor hood of 62MPH at about half throttle. Stock teh mariner has a 1.75 gear ratio but the owner told me he had it replaced b/c of a broken tooth with a 1.87 that he found a good deal on. I haven't checked the ratio yet to verify this though. The motor responds to no trim. It just increases the RPM and sounds a if the prop starts slipping. The hull looks real close to an eliminator or cougar. the motro has a Bob's nose cone, 3" cut out of the lower exhuast case and modified cowling to increase air flow into it. i would like a prop that would pull me 265lbs. and my girlfriend 110 lbs w/ our ice chest out of the hole fine w/ good midrange and top end. I was told somewhere around a 26p 3 blade round ear. If my gear ratio is different how much should I change the pitch. The owner said the fastest prop he had on it was a 27p 3 blade round ear, 78MPH but that was before teh gear change. Any help would be much appreciated.

Barney
06-07-2001, 11:28 AM
First your rev-limiter should be at 6700, not 6200.

That high five would be a good ski prop if you had a ski boat.

The best prop I have found for your setup would be a Yamaha Drag, call Kevin at R&R Props 702-564-7502, he has helped many of us that own Liberators. (I have two). A 26p Yamaha would serve you really well! On a stock 200hp 2.4, the 26 Yamaha pushes my 21ft Liberator to 80mph on GPS, with a 1.87 gear set.

Kevin has some new 4 blade Hydromotives that would work well also.

Propster has a 19 ft Eliminator Daytona with 245 hp, running very close to 100mph.

Round ear props are typically for bow lift, which you should not need, try to keep as much weight in the back of your boat as possible, Ice chest for sure.



[Edited by Barney on 06-07-2001 at 11:32 AM]

gtsmpuc
06-07-2001, 11:47 AM
Your right onthe prop I have now. i probably can pull 4 skiers with it. I'm looking through a service manual now to try to verify the rev limiter setting. That's what the previous owner told me and when I run this prop that is where it stays at. Although the motor doesn't seem to cut out or anything like that it just hits 6,200 and will bounce betwen their and 6,100. Do you think the prop would do that? Anyways I will call that shop and see what they have to say

gtsmpuc
06-07-2001, 11:52 AM
In the manual I found that when I reach 6,100 RPM the timing will retard to get it back down to 6,00 and if RPM hits 6,500 then timing will rapidly retard to 2* ATDC. I guess I need to investigate why this is so low. Do you know anything about the internals of the mariner. It is a 3 liter block but doesn't produce the 300 horsepower like the Merc.

Barney
06-07-2001, 12:31 PM
I also have the 3 liter block on my 300 Mariner, rev limit says 6100, functions at 6300 though.

I do not know much about your particular motor, seems a bit of an odd set-up with that big block on your light boat.
I do believe there are some bolt on packages that can get you up in the 280hp range pretty easily, Bakers may have a package set-up already for that motor.
I personally do not care for the individual, but on the links for Scream and Fly, Performance Plus has some mods set-up for your motor that will allow you to spin it much higher.

You may want to try spinning some larger wheels also, something along the lines of a 30p cleaver.

Good luck


[Edited by Barney on 06-07-2001 at 12:42 PM]

Todd
06-07-2001, 01:08 PM
I agree with Barney, Call Kevin. This guy really knows his stuff and is well connected. I'm getting a set of 30 cleavers from him now for my Liberator.

R&R 702 564-7502 or mailto:kevin@randrpropshop.com

Be real careful with trim and round ear props on the Liberators!

gtsmpuc
06-07-2001, 03:09 PM
Do you have a phone number or website for them by chance? I'm new to the whole outboard scene. I think the guy before just got a killer deal on the motor. I talked to Kevin and the weight also stumpped him a little, but I will probably wind up getting a yamaha 28p drag 3 blade.

Todd
06-07-2001, 04:01 PM
Here is the formula to calculate your speed with the new prop. The main variable is slippage.

RPM / gear ratio * pitch / 5280 / 12 * 60 = 100 speed. Multiply that by .9 to get approx. speed, normally +/- 2%

The .9 is for slippage.

TUNNEL T
06-19-2001, 10:01 PM
TODD YOU LOST ME ON YOUR FORMULA,ALL THAT MATH STUFF IS TO COMPLICATED FOR US DUMBAZZS MAKE LIFE SIMPLE GO TO HILL PROPELLERS AND LET THE COMPUTER FIGURE IT OUT FOR YOU ,JUST PLUG IN YOUR NUMBERS ! PRETTY ACURATE TO MY GPS. TUNNEL T(DISCOVERY BAY CA.)

racer
06-20-2001, 12:51 AM
Speed formula.... Rpm divided by ratio X pitch divided by 1056 equals max top speed, multiply by .9 to fiqure in slip.

Barney
06-26-2001, 03:32 PM
I thought I might here back as to whether those pictures may have shed some light on your situation?, boat pictures guys, calm down.

Did you receive them?

Did they help?

Why do naked girls prefer Liberators over all other boats?
That's right, it is the pilots!

Just testing!

gtsmpuc
06-26-2001, 03:43 PM
Yeah I got them. I've jsut been busy at work. I've never seen that much negative trim in my life. Have you ever tried using a hydrofoil to help you get out of the hole. I just laid one out that I'm going to give my machinist to make. It looks similat to the one Baker has. I haven't ever seen one of those mariner style alien cowls yet either. I'm going to have to get one. I'm not no expert but you probably should get a 24v trim set up. It ahs to take forever for your motor to get trimmed out. Do you think this could be part of your problem???? My boat sits about 2"-3" lower than yours in the water.I raced a Mirage over the weekend, he spanked me out of the hole 3-4 boat lengths boat then he barely pulled on me. he had a 2.5 w/ 300hp, so I think with more power I'll be OK. I'll send you some pics of my boat sitting on the trailer and hopefully I eill get some of it in the water shortly.

Barney
06-28-2001, 02:07 PM
They did help some, but I don't need em with the Bravo 1 and it still outperforms everything else on plane.

I jump out of the hole well, I just back off some to allow my motor to catch up so I don't take any facial spray. 24volt trim would help me to top end faster, spray free, but the reality of outrunning fast boats, over 100, is less important than the all around function of the smaller pitches. No more lake gas for me, so I show up with 50 gallons , add ice chest, at least one female passenger, gear, I have to give in somewhere, top end has the least value of these things mentioned most days.

I would suggest a tight fitting deck AND 3 bilge pumps, a good hand pump if you sit lower than me, I do get some boat wakes over the back, always gotta be watching it. Havasu and Lake Mead get very rough though, downright mean.

Your 19 can handle the hp, but it does get very sensitve over 100, easily will outperform my boat. Mine is more about "pimpin it".

Looking forward to seeing your ride!

gtsmpuc
06-28-2001, 05:39 PM
You live around Oklahoma, I'll run ya what you got?????

gtsmpuc
06-28-2001, 05:59 PM
Whatcha got?? I ahve to know what boat to bring!!!!!!!!!!!!

WILDMAN
07-20-2001, 12:12 AM
an easier formula is prop pitchXrpmX.535X.000946= speed with no slip. My liberator with twin 260's is 30 x 8600 x .535 x .000946 = 130.576 mph!!! On gps it's 122 mph. Works for me. If you're running 100 plus, you need to use cleaver to lift the ass-end, you don't want to lift the bow at those speeds, or you'll be seeing sky! good luck WILDMAN in Fl.

Barney
07-20-2001, 12:31 AM
http://www.boatpropellers.com is one.