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hkunz
08-27-2007, 08:32 PM
We are going to Powell in a few days, and I seem to remember someone saying that they had two different props for Powell and Havasu. Is there a big difference? Is it worth the $600 or so to get another prop? Mine accelerates great at Havasu, but does not have all the top end it could. Will this trait be exagerated or diminished at higher altitudes. I have no idea what the pitch, or cup, or diameter, or anything else is, although it is a four blade.

watergun4u
08-27-2007, 10:57 PM
Hi just thought that I would let you know that with that big of boat, and the 4 blade prop, I am assumeing here but I would say it is proboly around a
14 1/2x21, to 23 which is a good all around prop, you should have no problem running that prop, with no worry's!:D

phebus
08-28-2007, 06:58 AM
The characteristics your prop has with a good hole shot, but light on the top end should make it a good fit at Powell. If you had a prop that was set up for top end speed I would suggest dropping in pitch, but what you have sounds good. Not worth the cost of changing.

hkunz
08-28-2007, 08:29 AM
Advantage X-Flight 20 with the 600 SCi.

shippingguy
08-28-2007, 12:16 PM
We are going to Powell in a few days, and I seem to remember someone saying that they had two different props for Powell and Havasu. Is there a big difference? Is it worth the $600 or so to get another prop? Mine accelerates great at Havasu, but does not have all the top end it could. Will this trait be exagerated or diminished at higher altitudes. I have no idea what the pitch, or cup, or diameter, or anything else is, although it is a four blade.
With your motor setup you most likely are running 28 pitch 4 Blade Bravo One 15.25 diameter. Possibly a 26, but I would say either one or the other not smaller or bigger. I would run what you got or see if Advantage will let you borrow a prop just in case for the trip.
Mike

hkunz
08-28-2007, 02:11 PM
what prop do you have on it now ?,look at your prop it has a # on it
I have no idea, and the boat is at Advantage. I don't pick it up until Friday AM, and I have no internet at Havasu. However, they are looking at the boat and will call me back with the prop size. They think it is a 24. If they think it will need more (or less) prop they'll give me a loaner. Pretty cool. Cheetah sold us a new prop when we asked the same type questions.

hkunz
08-28-2007, 02:35 PM
what prop do you have on it now ?,look at your prop it has a # on it
I have no idea, and the boat is at Advantage. I don't pick it up until Friday AM, and I have no internet at Havasu. However, they are looking at the boat and will call me back with the prop size. They think it is a 24. If they think it will need more (or less) prop they'll give me a loaner. Pretty cool. Cheetah sold us a new prop when we asked the same type questions.

hkunz
08-28-2007, 02:42 PM
It is a 24 on it now, they will loan me a 22 for Powell. The Hot Boat tests were done with a 26.

redneckcharlie
08-28-2007, 03:05 PM
A good rule of thumb when it comes to elevation, is 4 to 5 percent loss per thousand feet of elevation gain. Your boat may pull the prop you have on it now, but will most likely have a hard time rolling over. Even with the drop to the 22, don't be surprised if you don't get all the rpms out of your boat.
The main lake here is a mile high and the higher elevation lake is around 6800. The customers I dealt with in the past that came from low elevations were always very shocked at the difference in performance with their boats. The way a boat performs here compared to Havasu is almost night and day. Good luck on your trip. :)

hkunz
08-28-2007, 05:38 PM
4400 lbs. It comes out of the hole like a scalded cat, then spins up fast all the way to 55 (the fastest i've had the boat so far). The motor will go much farther, but I'm still learning the boat.

shippingguy
08-28-2007, 06:00 PM
600sci and your only running a 24 at the zoo?how heavy are the x/f:idea:
I am on the same page as you. On my last Ultra 27 Shadow I had a 525 and would spin a labbed 28 and it would come out of the hole just fine and the boat is 5100 lbs. On my new one with a Teague 800 I can spin a 32 and a 34 in the cooler months. That 600 should be able to spin a 28 no problem.

ULTRA26 # 1
08-29-2007, 07:45 AM
I am on the same page as you. On my last Ultra 27 Shadow I had a 525 and would spin a labbed 28 and it would come out of the hole just fine and the boat is 5100 lbs. On my new one with a Teague 800 I can spin a 32 and a 34 in the cooler months. That 600 should be able to spin a 28 no problem.
Mike,
There is an article on this boat in HB. The boat is no rocket. With a 600 and a 26, the boat ran 70.4. The test drivers complimented the boats ride and turning ability. IMO, a 22P behind a 600 in any boat, is under proped, at any elevation. One of the advertised features of the 600 in an ECU that adjusts for altitude.

It's Only Money
08-29-2007, 11:02 AM
4400# Boat with a 600SCI and a 26P prop only 70? Something ain't right.

redneckcharlie
08-29-2007, 11:14 AM
Mike,
There is an article on this boat in HB. The boat is no rocket. With a 600 and a 26, the boat ran 70.4. The test drivers complimented the boats ride and turning ability. IMO, a 22P behind a 600 in any boat, is under proped, at any elevation. One of the advertised features of the 600 in an ECU that adjusts for altitude.
If a boat will only turn a 22 prop at elevation to the max rpm, its hard to say its underpropped. The reality is that if thats all the prop it will spin, there is absolutely no reason to use a bigger wheel. As far as the ECU goes, it will adjust the fuel to air ratio, but it will not make up for the lack of oxygen at elevation. Many people have never experienced the difference elevation will make on the performance of there boats. In many cases, it makes people think there is something wrong with motor. I would have to agree that you would think 600hp would run a little better in that boat. When I was at the LA Boat show this year I looked at the new 29, and its defenitely not a small boat. Tons of room and space. Very pretty boat!;)

shippingguy
08-29-2007, 11:15 AM
4400# Boat with a 600SCI and a 26P prop only 70? Something ain't right.
Again, I would agree with this statement. This boat should be running better with a 26 and should actually be able to spin a 28 with no problem. Something is not right. This boat is way under propped. A 24 is way too small.
Mike

hkunz
08-29-2007, 11:19 AM
I think it's topped out with the prop setup we have. The acceleration numbers in Hot Boat were the best in the group, so, IF i understand the prop ratio thing correctly, a larger number prop should give better top end but poorer acceleration. The 26 was probably too small, thus only 70. OBTW, the tattletale on the GPS speedo says 75, but i don't know who/when that was done.

shippingguy
08-29-2007, 11:32 AM
I think it's topped out with the prop setup we have. The acceleration numbers in Hot Boat were the best in the group, so, IF i understand the prop ratio thing correctly, a larger number prop should give better top end but poorer acceleration. The 26 was probably too small, thus only 70. OBTW, the tattletale on the GPS speedo says 75, but i don't know who/when that was done.
It is good to have acceleration, but you could run a bigger prop than you are and you will see that you will still have great acceleration. You have 600 Blown HP. With the bigger prop you will be able to cruise at higher speeds at less RPM in turn putting less strain on the motor/drive and improve fuel economy as well as top end. Just my .02.
Mike

redneckcharlie
08-29-2007, 12:19 PM
Hey Hkunz, I'm curious. Whats the max rpm you get out of your present set up? Are you sitting on the rev limiter with any throttle left? I guess I'm a little confused with some saying to run a bigger prop. If a boat turns a 24 to say 5200 rpm, and thats the max the boat will pull, going to a larger prop will not gain you anything. Depending on how the X Dimension is set up on a boat, each prop size jump or descrease, is good for 200 rpm either way. Just because a boat will turn a 24 to 5200rpm does not mean it will turn a 26 to 5200rpm. Being over propped will defenitely change the way your boat planes. If its to big, it may not plane at all depending on your load. If the boat is propped correctly, it should be just under its rev limiter without any throttle left. By under I mean within 100rpm, or so. The weight that is stated for your boat seems light to me. That boat looks much larger than the weight Advantage states. Do you have any idea what the weight is fully loaded?

shippingguy
08-29-2007, 12:38 PM
Hey Hkunz, I'm curious. Whats the max rpm you get out of your present set up? Are you sitting on the rev limiter with any throttle left? I guess I'm a little confused with some saying to run a bigger prop. If a boat turns a 24 to say 5200 rpm, and thats the max the boat will pull, going to a larger prop will not gain you anything. Depending on how the X Dimension is set up on a boat, each prop size jump or descrease, is good for 200 rpm either way. Just because a boat will turn a 24 to 5200rpm does not mean it will turn a 26 to 5200rpm. Being over propped will defenitely change the way your boat planes. If its to big, it may not plane at all depending on your load. If the boat is propped correctly, it should be just under its rev limiter without any throttle left. By under I mean within 100rpm, or so. The weight that is stated for your boat seems light to me. That boat looks much larger than the weight Advantage states. Do you have any idea what the weight is fully loaded?
Well they tested his boat in last month's Hot Boat and they ran a 26 on it. He stated he is running a 24 now. He also stated the 26 was a bit too small in one of his previous posts.
Mike

shippingguy
08-29-2007, 12:44 PM
hkunz:
BTW I am not knocking your boat's performance at all just trying to figure it out and see if I can help you. Hope you do not take anything the wrong way.
Mike

redneckcharlie
08-29-2007, 01:27 PM
Well they tested his boat in last month's Hot Boat and they ran a 26 on it. He stated he is running a 24 now. He also stated the 26 was a bit too small in one of his previous posts.
Mike
So they ran a 26 in ***boat? With how much gas? With how many people on board? With how much gear on board? What was the temp outside? I guarantee that boat was outfitted to have the best performance, but was no where near set up for everyday use. Theres not a manufacturer out there that doesn't do that. :rolleyes:

ULTRA26 # 1
08-29-2007, 01:30 PM
I think it's topped out with the prop setup we have. The acceleration numbers in Hot Boat were the best in the group, so, IF i understand the prop ratio thing correctly, a larger number prop should give better top end but poorer acceleration. The 26 was probably too small, thus only 70. OBTW, the tattletale on the GPS speedo says 75, but i don't know who/when that was done.
When I read the HB review, I too thought that the 26P prop was too small. Merc's HP600 is a stout package with huge torque numbers. If I were you I would reconsider using a 22P prop for Powell as you will burn an unnecessary amount of fuel just to cruise. Your 4400 lb 29' boat, once dialed in should run at a minimum of high 70's, and I expect that it will.
Extremely nice looking boat. Have a safe trip. Powell is beautiful.
John M
If a boat will only turn a 22 prop at elevation to the max rpm, its hard to say its underpropped. The reality is that if thats all the prop it will spin, there is absolutely no reason to use a bigger wheel. As far as the ECU goes, it will adjust the fuel to air ratio, but it will not make up for the lack of oxygen at elevation. Many people have never experienced the difference elevation will make on the performance of there boats. In many cases, it makes people think there is something wrong with motor. I would have to agree that you would think 600hp would run a little better in that boat. When I was at the LA Boat show this year I looked at the new 29, and its defenitely not a small boat. Tons of room and space. Very pretty boat!;)
Merc claims that the system in this boat will increase boost to compensate for the loss of oxygen at higher elevations. Obviously the twin screw on this motor can only pump so much air. The HB article claimed the weight of this boat at 4400, which I agree seems light.

shippingguy
08-29-2007, 01:34 PM
So they ran a 26 in ***boat? With how much gas? With how many people on board? With how much gear on board? What was the temp outside? I guarantee that boat was outfitted to have the best performance, but was no where near set up for everyday use. Theres not a manufacturer out there that doesn't do that. :rolleyes:
Well you may be right. I just find it hard to believe that a 4400 lb boat with 600 HP cannot run a bigger prop efficiently. Like I previously stated I had another 27 Shadow that weighed 5100 lbs dry and under normal conditions I could hop up on plane and run right at the rev limiter with a labbed 28and a 525. I can tell you it was 100 plus degrees out there. I had my boat out that same weekend for a photo shoot with Hot Boat. As for the manufacturers setting there boats up for best performance #'s there are many out there that do, but I can tell you the Ultra that was out there was set up the exact same way as when you pick it up on delivery day.
Mike

redneckcharlie
08-29-2007, 02:10 PM
Well you may be right. I just find it hard to believe that a 4400 lb boat with 600 HP cannot run a bigger prop efficiently. Like I previously stated I had another 27 Shadow that weighed 5100 lbs dry and under normal conditions I could hop up on plane and run right at the rev limiter with a labbed 28and a 525. I can tell you it was 100 plus degrees out there. I had my boat out that same weekend for a photo shoot with Hot Boat. As for the manufacturers setting there boats up for best performance #'s there are many out there that do, but I can tell you the Ultra that was out there was set up the exact same way as when you pick it up on delivery day.
Mike
I completely agree with you about 600hp in a 4400lb boat. I just highly doubt that boat is 4400lbs. I'd bet its quite a bit heavier. His 29 compared to one of my old 28Heats, or even my old Mach 26, is huge in comparison. That is one of the largest 29's I've ever seen. Ultra 26, I don't have any experience with the new merc 600sc, but Merc claiming that they can adjust boost to compensate for altitude is nothing more than marketing in my opinion. Unless theres some type of adjustable blower pulley on the motor, theres not a whole lot of boost adjusting going to happen. Thats meant with great sarcasm, not towards you, towards merc. There is nothing any engine manufacturer can do to make up for the lack of air. One of the hardest things I ever had to deal with was customers that came from sea level, or near sea level, and get them to understand how much the elevation change really affects their boats performance. Its not that they were ignorant or dumb, just very few people boat at high elevations. A mile high is a huge elevation change from sea level. Many people that come up here during balloon fiesta have a hard time breathing until there body adjusts. As far as Lake Powell goes, its around 35 to 36 hundred feet. Going from Havasu to there, you'd have to drop atleast one prop size. I hope you guys don't take this as me trying to be a know it all, because its not meant that way at all. I've just had a ton of experience with the whole altitude deal. I've played with props so much it isn't even funny. And expensive. I was having to set up boats from 16 to 30 feet, with several different manufacturers. The bad part was that the vast majority of the manufacturers couldn't give me a whole lot of advise, so I ended up doing all my own homework. ;)

hkunz
08-29-2007, 02:49 PM
Wow, I'm getting a lot of great input, and I don't even know what to say:)
I don't think I've ever had it on the rev limiter. I've seen 5400, which the Merc book says is the rev limit, but that was for only a sec during acceleration, and I pulled it back. That was only once. I've only had the boat to 55 MPH, since I'm still learning how to drive it.
Advantage specs it at 4400 pounds. That is with engine, but not fuel - 110 gallons at 7 pounds each is another 770 pounds, making it 5170, correct?:idea:
We ususally go with just my wife and myself, so that's what we would set it up for. When the kids come, it seems from this thread that I should possibly reprop? (each kid at 200 to 300 pounds per - one 250 pound DIL, one 350 pound kiddo, that's another 600 pounds)
Should I perhaps wait until I can check it out more before I mess with props? I should mention that my wife is not into "test and tune", so I need to go the right way rather quickly;)

redneckcharlie
08-29-2007, 03:15 PM
Unfortunately theres no easy way to figure out which prop is the best fit. It helps greatly to have access to a few different demo props, or buddies that have some various pitches. As far as testing goes, I always did that with a half fuel load and the number of people in the boat that would most likely be present when the boat was used. I usually started with a prop I knew was going to be to big. If I knew the boat was over propped and only reached say 4600rpm, with say a 28(bravo), and I needed 5150, then I knew I could drop to a 24, and get to 5000rpm. I could usually gain the other hundred or so rpm with prop labbing. The two hundred rpm gain or decrease for prop size always worked well for me, and then I would use the labbing to fine tune the rest. There were a couple places in Havasu that had demo prop programs, and they were also very capable of labbing. If my memory serves me right, the one I used the most in Havasu was, The Prop Shop. He was very reasonable and did great work. Good luck.

It's Only Money
08-30-2007, 11:00 AM
Hey RedNeck....what about an adjustable waste gate? Been done before.

NuckinFutz
08-31-2007, 06:05 AM
Wow, I'm getting a lot of great input, and I don't even know what to say:)
I don't think I've ever had it on the rev limiter. I've seen 5400, which the Merc book says is the rev limit, but that was for only a sec during acceleration, and I pulled it back. That was only once. I've only had the boat to 55 MPH, since I'm still learning how to drive it.
Advantage specs it at 4400 pounds. That is with engine, but not fuel - 110 gallons at 7 pounds each is another 770 pounds, making it 5170, correct?:idea:
We ususally go with just my wife and myself, so that's what we would set it up for. When the kids come, it seems from this thread that I should possibly reprop? (each kid at 200 to 300 pounds per - one 250 pound DIL, one 350 pound kiddo, that's another 600 pounds)
Should I perhaps wait until I can check it out more before I mess with props? I should mention that my wife is not into "test and tune", so I need to go the right way rather quickly;)
If you've seen 5400 rpms, only 55 mph and haven't stayed with it for any amount of time, I'd say your currently running to small of pitch. If at 5400 you were only getting 55, your never going to get to 70. Powell will take about 400 rpms off a regular V-bottom boat (my 25 Citation as example) from Havasu. I would think a 22 would be much to small. I run a 24 at Powell with a 496 under the hatch.

It's Only Money
08-31-2007, 10:47 AM
I reread the Hot Boat article on Advantage X-Flight...
70 MPH @ 5,000 RPM with a 26P prop? That calculates to 14.7% slip.

hkunz
09-02-2007, 07:25 PM
I just keep getting more and more confused:)
I have the 24 on there, and have a 22 "loaner" from Advantage in the truck. We'll get there tomorrow and mess around finishing the programming of the electronics, getting the fishing licenses, and seeing if I can get through the mussel check, whatever it is, then I have to take the boat apart to test place the transducer, (I'll do a fishfinder in a new Advantage how-to thread later) so I can put the boat in early Tuesday to go up to Rainbow Bridge. If I think that the boat won't plane, I'll try the 22 then.
The 5400 before I got to 55 was on initial acceleration - if it was in my Camaro and behaved as it does on acceleration with the 24 at Havasu, I'd lift a little to hook the tires back up. It seems as though it is accelerating quickly, but frying the tires along the way. That's why I pulled it back - I was going as fast as I wanted to and no more throttle was needed. RPMs dropped to 4k at 50-55 cruising. I know that I am probably not stating this correctly, being unfamiliar with the mega motor/prop terminology.
Several responses have discussed "lab" props. What is that, exactly? Polished? Trued? Both? Knife-edged? Leading or trailing edge? How does it work on props that might be damaged by rocks or trees (after labbing)?
Is 14.7% slip bad, good, or middle? Could that be the "not hooked up" feeling I get?
Why would Advantage tell me that the 28 would not be a good idea? Becaus they know I can't drive it well yet?

It's Only Money
09-04-2007, 10:53 AM
14% slip seems excessive. Maybe others will chime in with their opinions. Think of a prop as a big screw...every time you turn the screw it should move deeper into the wood by the value of the pitch. For a 24P (pitch) prop, every turn should theoretically (with no slip) move the boat forward 24". With 14% slip, you actually are only moving forward 20-1/2" or so. That would indicate either - the hull is not efficient or the prop is "hooking" up to the water. Different props act differently. With a boat so new, a different style prop may be needed to reduce the slip.
Other opinions?

OLD MAN ON THE LAKE
09-04-2007, 11:50 AM
Trim The Boat.

hkunz
09-04-2007, 06:05 PM
I tried a number of things today while on the way up to Rainbow Bridge and back. From a stop, I can get 4800 RPM well before 20 MPH, then the boat comes on rapidly and we shoot up through 50-55 if I don't pull back (the wife likes 35 - 45). When I pull it back, I can cruise at 40 MPH at 3100 RPM. It seems as though the prop is blowing out, like when the tires break loose, then catch as you let off.
Another strange thing happened several times, don't know if it is prop related, or if I have a clutch that is going south (do Bravo One XRs have clutches?). The RPM jumped down suddenly without a change in speed or throttle position. It also went up similarly. Since it happened randomly, I don't have a delta of RPM change, but I's guess at least 200-300. I was on plane at the time, each time it happened.
I hit the trim up as I accelerate, starting about 25 MPH. I'll try starting lower tomorrow.
Hooking the prop?

redneckcharlie
09-04-2007, 08:17 PM
Please don't take this wrong, but it really sounds like it would benefit you greatly to have someone go out with you and give you some pointers on how to drive your boat. It may save you alot of frustration in the long run. Good luck! Its a beautiful boat. ;)

hkunz
09-04-2007, 08:37 PM
LOL, Advantage took me out:) I think I may be looking for more than what they were able to show me. My wife thinks all is well - maybe it is.

It's Only Money
09-05-2007, 11:12 AM
It sounds as you're pretty much a newbie so I'll try to offer some pointers.
First, invest in a good hand held GPS so that accurate speed measurements can be taken by a second person on board who will write everything down. Don't trust any kind of speed measurement other than GPS or radar which is prohibitively expensive to own.
Next, with the trim all the way down, accellerate from a dead stop - not by hammering the throttle down but just smoothly pushing the throttle forward. When you get to an even cruise at about 3000 RPM raise the trim a little bit. Wait about 30 seconds or so for the boat to settle at the new trim setting and write down the speed on the hand held GPS at 3000 RPM. You might have to adjust the throttle a tiny bit to keep 3000 RPM after raising the trim. (Hopefully you have some sort of trim indicators) Note the trim setting, speed and RPM. Now, raise the trim a little more and wait another 30 seconds and note the same details. Keep doing this until you start to slow down. That indicates OVER trimming. Go back to the trim setting that gave you the best speed at 3000 RPM.
Now increase to 3500 RPM and try adjusting the trim again to find the best speed. Note all the factors - speed, trim setting and RPM.
Repeat at 4,000 RPM and again at 4500 RPM - always noting the 3 factors. You should find (typical) that as you give the boat more throttle, you need to give it more trim to get the best possible speed. For example on my 25 Eliminator Eagle I cruise at 2-3 on the trim gauge but wide open throttle it like up around 6.
You should NOT be "blowing out" if you have the right prop. I suspect you don't have the right prop for that hull. From what I've read in print and online about your hull is it is very different that other hull designs. It is also unproven and brand new and I doubt that Advantage has test a wide variety of prop designs to optimize the prop selection to the hull.
The notes I told you above to collect will help you if you decide to find the right prop as you'll need them for reference when dealing with prop shops or manufacturers. Also make notes as to approximate air temp and altitude as these play a part in making horsepower. Note as well the amount of fuel and weight of items you have with you on the test runs. Try to make the same measurements each time you test.

DMOORE
09-05-2007, 01:14 PM
After reading the entire thread, and all the specs from the Hot Boat article I'll say this.
Leave the 24 pitch on, and have a great trip to Powell. All will be well.
You can play with the props after you return, and have more seat time in the boat.
Darrell.

hkunz
09-05-2007, 03:31 PM
I've just been playing around with it here at Powell. The 24 has worked great, and I think we are doing very well on fuel. We went to Dangling Rope and skipped the fuel stop, since it was still on full (indicated), then on to Rainbow Bridge, (gorgeous), then Secret Canyon, then several others, then back to Dangling Rope for ide cream, then back down towards Antelope (where we have a slip) messing around all the while. We were only at half tank, but we gassed up this AM to go out fishing and testing and sightseeing:D Only took quarter tank. That all tells me that the prop and boat are working pretty well together up here.
Only got 60 at 5100 RPM during a speed test run, but backed out because of traffic. It still had more. I was messing with the trim and it would slow and speed up as I changed it.
I also tried trimming from a start - it blew right out, threw water up out of the stern. Too much trim. Went back to the trim settings relative to speed that Advantage recommended, worked much better.
While swimming, I found small nick (with a sharp edge) in the prop - don't know when I got it, but it is there. I'm thinking any testing has to be put on hold until I get that nick fixed/new prop. It could be at least part of the reason for the "prop blow out" that I've just started experiencing. The other thing that could be causing this change is the drive shower I just had put on - NOT a Rex shower, they don't fit the finned cover on the XR. The little pipe that sticks down could be causing some cavitation, perhaps.
I'll mess with it all more back at Havasu. For nlow, the boat works great, the food is great, the scenery is simply amazing. We went way into Face Canyon and way up Warm Creek today, and we are wiped out:D
Thanks to all for the great advice and ideas.

Zimm944
09-05-2007, 08:07 PM
With the motor you have there is know way you should run a 22p. I have a 28 eagle with a HO and I run a 22 and could probably run a 24. I would think with that motor you could run a 26. Also I had a company but on a drive shower wrong and it made it cav bad, the remounted it and it runs great again. I would think its your prop and not the shower. Also i have a rough spot in my prop and it does not hurt the performance, not sure how big your nick is but it is probably not hurting the performance.

hkunz
09-11-2007, 11:24 AM
OK, back at Havasu, 3/4 tank of gas, no wife (she was getting the trailer), no traffic, medium chop, and the kill switch hooked to my swimsuit, I ran from Windsor to Havasu Landing and back. I hit 5500 RPM, 100 over the Merc rev limiter (perhaps a tach calibration issue?) as I passed through 70 MPH (GPS)with a ton more trim than Advantage showed me. I say "passed through" because I was paying attention to the RPM and the water at that speed, and only glanced at the speedo. When the RPM hit 5500 I shut her down a bit. The boat tracked straight and true, easy to handle, but I wasn't taking any more chances than I already was by running at that speed. Yeah, when I was a bit younger I ran the Tahiti up at speeds like that (6" off the water!), but I was more invincible then, and didn't have a huge boat payment.
Anyway, I am now thinking I am underproped for my primary lake, based upon what you guys have said. I also still have the "blowout" issue, and after comparing the Imco drive shower pickup on the Advantage to the Cheetah's much smaller shower pickup, I am almost convinced that the shower pickup is the issue. I figure I'll modify the pickup before I spring for a new shower, although I don't like the way the hose is stretched so it fits the ~2" x-dimension spacer. My next step is to have the nick cleaned up and the Propeller Company fiddle with it, and chop the shower pickup.
My goal here is to have the boat be the optimum all around boat that get (fairly) good mileage, has good power, and can handle the loads of the family. To me, getting the prop right on is part of that, then I can go on to other things. I really appreciate all the advice and ideas - the rethinking my trim was a great idea!

It's Only Money
09-12-2007, 11:13 AM
OK, back at Havasu, 3/4 tank of gas, no wife (she was getting the trailer), no traffic, medium chop, and the kill switch hooked to my swimsuit, I ran from Windsor to Havasu Landing and back. I hit 5500 RPM, 100 over the Merc rev limiter (perhaps a tach calibration issue?) as I passed through 70 MPH (GPS)with a ton more trim than Advantage showed me. I say "passed through" because I was paying attention to the RPM and the water at that speed, and only glanced at the speedo. When the RPM hit 5500 I shut her down a bit. The boat tracked straight and true, easy to handle, but I wasn't taking any more chances than I already was by running at that speed. Yeah, when I was a bit younger I ran the Tahiti up at speeds like that (6" off the water!), but I was more invincible then, and didn't have a huge boat payment.
Anyway, I am now thinking I am underproped for my primary lake, based upon what you guys have said. I also still have the "blowout" issue, and after comparing the Imco drive shower pickup on the Advantage to the Cheetah's much smaller shower pickup, I am almost convinced that the shower pickup is the issue. I figure I'll modify the pickup before I spring for a new shower, although I don't like the way the hose is stretched so it fits the ~2" x-dimension spacer. My next step is to have the nick cleaned up and the Propeller Company fiddle with it, and chop the shower pickup.
My goal here is to have the boat be the optimum all around boat that get (fairly) good mileage, has good power, and can handle the loads of the family. To me, getting the prop right on is part of that, then I can go on to other things. I really appreciate all the advice and ideas - the rethinking my trim was a great idea!
Next time take a hand held GPS if you don't (sounds like you don't) have a tattle tail tach. You can get a hand held Garmin GPS for less than $100 and it'll usually (depends on model) let you zero-out your trip and then recall your top speed. I use a Garmin GPS IV+ that does this but they have much new models. This will be invaluable it you are truly trying to find the right prop. Also, your tach may be off as the rev-limiter should have kicked in before reaching 5,500 RPM.
Do you have hydraulic steering? If not be very wary of exceeding 70 mph with just cable steering. If the cable breaks you die. No more boat payment for YOU!

hkunz
09-13-2007, 09:30 AM
I took out the tattletale's switch and mounted it in the helm console temproarily when I installed the flush mounted Garmin sounder. I could probably get the max speed out of the Garmin, I didn't think of that. I could also wait until I install the flush mounted VHF, which will give me the final location for the tattletale switch (the tattle tale switch was in the middle of prime real estate for mounting electronics).
We have full hydraulic steering, no cables at all.
I should get the VHF and tattle tale mounted this weekend - no boating, just boat work.

ULTRA26 # 1
09-13-2007, 05:32 PM
I completely agree with you about 600hp in a 4400lb boat. I just highly doubt that boat is 4400lbs. I'd bet its quite a bit heavier. His 29 compared to one of my old 28Heats, or even my old Mach 26, is huge in comparison. That is one of the largest 29's I've ever seen. Ultra 26, I don't have any experience with the new merc 600sc, but Merc claiming that they can adjust boost to compensate for altitude is nothing more than marketing in my opinion. Unless theres some type of adjustable blower pulley on the motor, theres not a whole lot of boost adjusting going to happen. Thats meant with great sarcasm, not towards you, towards merc. There is nothing any engine manufacturer can do to make up for the lack of air. One of the hardest things I ever had to deal with was customers that came from sea level, or near sea level, and get them to understand how much the elevation change really affects their boats performance. Its not that they were ignorant or dumb, just very few people boat at high elevations. A mile high is a huge elevation change from sea level. Many people that come up here during balloon fiesta have a hard time breathing until there body adjusts. As far as Lake Powell goes, its around 35 to 36 hundred feet. Going from Havasu to there, you'd have to drop atleast one prop size. I hope you guys don't take this as me trying to be a know it all, because its not meant that way at all. I've just had a ton of experience with the whole altitude deal. I've played with props so much it isn't even funny. And expensive. I was having to set up boats from 16 to 30 feet, with several different manufacturers. The bad part was that the vast majority of the manufacturers couldn't give me a whole lot of advise, so I ended up doing all my own homework. ;)
While I don't know for sure, I was under the impression that, on the HP600, boost was maintained with an electronic wastegate type valve. Don't think this sounds to complex. I will try to verify.

hkunz
09-17-2007, 07:49 PM
It turns out the computer was the culprit on my thinking that the prop or shower was causing the RPM change. It is at Advantage now so Alco can look at it. They'll change out the prop, too, and do some other work. I can't say enough about how impressed I am with the entire Advantage crew and thier customer service.:D

Decided Advantage
09-18-2007, 03:52 AM
While swimming, I found small nick (with a sharp edge) in the prop - don't know when I got it, but it is there. I'm thinking any testing has to be put on hold until I get that nick fixed/new prop. It could be at least part of the reason for the "prop blow out" that I've just started experiencing. The other thing that could be causing this change is the drive shower I just had put on - NOT a Rex shower, they don't fit the finned cover on the XR. The little pipe that sticks down could be causing some cavitation, perhaps.
I'll mess with it all more back at Havasu. For now, the boat works great, the food is great, the scenery is simply amazing. We went way into Face Canyon and way up Warm Creek today, and we are wiped out:D
Thanks to all for the great advice and ideas.
Dude, I don't know what your nick looks like but don't worry to about it. It sounds like you had a great time on the water and are breaking in a new engine about right. I personally keep a small stone around to knockoff the rough spots. This situation unfortunately happens often enough that I could never consider a labbed prop, I'll leave that to the builders trying to put the best number in the mags.
If your crew packs like mine you'd gain 5 at this point by cleaning all the stuff out of the boat.

hkunz
09-18-2007, 02:54 PM
What, you mean I shouldn't carry two easy ups, a ton of chairs, enogh life jackets for the Titanic, an air pump, and food for 30?:D
Looking at other props I figured my nick was way small, but i had the prop cleaned up so I could trade it for a 26. Reading the instructions (doh) I found that Mercury Racing says the prime RPM spot is about 4800 to 5000. This means I need to lose the extra RPM, so a 26 is the right direction.:idea:

shippingguy
09-18-2007, 07:35 PM
What, you mean I shouldn't carry two easy ups, a ton of chairs, enogh life jackets for the Titanic, an air pump, and food for 30?:D
Looking at other props I figured my nick was way small, but i had the prop cleaned up so I could trade it for a 26. Reading the instructions (doh) I found that Mercury Racing says the prime RPM spot is about 4800 to 5000. This means I need to lose the extra RPM, so a 26 is the right direction.:idea:
The Merc 600 can run above 5000. It can run up to 5200. You are cutting yourself short. JMO
Mike

DMOORE
09-19-2007, 09:02 AM
What, Reading the instructions (doh) I found that Mercury Racing says the prime RPM spot is about 4800 to 5000. This means I need to lose the extra RPM, so a 26 is the right direction.:idea:
Basically you want to prop the boat so that with 2 people, 1/2 fuel and perfect conditions, you will bump the limiter. Then with a full compliment of crew and loaded for bear you will be a few hundred RPM's lower. This will also give you a nice cruise rpm. The 26 should be perfect for the boat as an overall do everything prop.
Darrell.

hkunz
09-19-2007, 09:48 AM
The Merc 600 can run above 5000. It can run up to 5200. You are cutting yourself short. JMO
Mike
Oh, it'll run above 5 grand, I've had it to 5500, but I don't want to be there all day, and I want to optimize the compromise for best all around performance with best efficiency (I alsmost said "economy", but then I wouldn't have a 600 SCi). As a bonus, it is costing me nothing but a little wrench turing to swap out the prop and test it.

It's Only Money
09-19-2007, 10:57 AM
If you're hitting an indicated 5,500 RPM I'd seriously look into having your tachometer calibrated against a reference tach. The rev limiter should be kicking in long before that. I don't off hand know what it is set at for the 600 but the 502 I have it is set for 5,050 and kicks in right at that point according to my Livorsi tach. Have Advantage and/or Alco Marine check your tach. Alco has a water tank and should also have a calibrated tachometer that they can connect. Mercury Racing has been known to ship the wrong resistors in their wiring harness for the tachometer lead - thus giving inaccurate results.

hkunz
09-20-2007, 12:08 PM
They are lookng at it as we speak (type), thanks for the ideas. They are taking it out on the water today to investigate.

hkunz
10-03-2007, 01:40 PM
Here's what we found: On the very first day, when the boat was delivered, I didn't push the "trailer" switch far/long enough. I knew at the time because of the noise, and we drug the prop a very short distance up the ramp at Windsor. :mad: I put it all the way up and we went on. I knew it had a nick in it, which I got taken out by the Propeller Company. I didn't have them balance it or "lab" it.:idea:
The shift in speed was caviatation!:jawdrop: Scott at Advantage took Alco out with their diagnostic tools and ran it and got the same results we did, but it didn't throw any codes. They then swapped props to a labbed 24 test prop they have, and it stopped the cavitation.:) It seems the blade that was drug, even for that short time, has a different pitch than the rest of them, so three blades push at a different rate than the single bent one, causing cavitation and a shift in RPM.
They did some testing with the bent prop, since I was out for the regatta, and the last weekend of the year, and found that pushing the boat with even more trim would stop the cavitiation. And it does.:) By going to 3/4 trim the boat jumps up in speed and drops in RPM, so now I have a different acceleration/trim curve than what I was doing, and it works great. Next up, get the prop down to Gibbs and get it fixed and labbed.

hkunz
04-29-2008, 01:25 PM
Another ancient post revisted....:idea:
Since this post, I had the old (six months) prop balanced by Gibbs, and it woke the boat up. I was now on the limiter quickly at part throttle. That told me to try the 26, which got me to not quite on the limiter at full throttle, but blows out the prop at startup, so I got it labbed. It still blows out on acceleration, but not near as bad, and I can run up to 65 very quickly (more speed is available, it just takes a while longer).