Prop Questions

[Rivercrazy]

I have a 2003 Shockwave 25 Tremor closed bow with a 496HO and Bravo1X. Â*I've been running two prop's.

A box stock 23P Merc Revolution-4 seems like a good all around prop. Â*The best GPS I've seen is 70.4 in high 80 degree temps. Â*Rolls the boat over pretty quick and has good overall handling with no blowout in turns and respectable mid range cruise (55mph on GPS at 4,000 rpm). Â*I can turn this prop in the 5100 rpm range and have banged the rev limiter a few times in cooler weather.

The other is a Merc Mirage Plus 25P 3 blade lab finished by York Prop's. Â*The best speed I've seen with this prop is 73 in mid 80 degree temps. Â*It cruises at 4,000 rpm at 60 on GPS (not bad ehh?). Â*Mid range accel is outstanding. I can turn this prop about 5,000 rpm and have never hit the rev limiter with it. However, its not a great all around prop for everyday use. Â*It rolls over slower and vent's in the turns. Â*Turning a tight arch at slow speeds with a heavy throttle hand will blow it out on occasion. Â*Its also not the best prop for carrying lots of peeps and heavy loads. Â*Bottom line is it seems like a great top end wheel.

Both props carry the nose of the boat well. Â*The 4 blade does feel like it provides stern lift in addition to bow lift. Â*

I've heard from a few people that the 496's like to be a little underproped and not rung out to the rpm peak the engine is rated for. Â*Given that, has anyone tried other props on this boat? Â*Perhaps a 24P or 26P Merc Bravo-1 4 blade? Â*Any other suggestions or anyone with experience running different props on the 25 Tremor?

[Essex502]

I think KC on (KC_Nelson) is using a Bravo 26P on a 28' Nordic Heat which is a bigger boat than yours. Don't know if it equates but it seems that the 496's like more prop rather than less.

[kevnmcd]

RC - The only other person on this board with a Tremor is Beer Hunter. He is out of town for the next week so won't be responding to this before then, but I know that he has not experimented with any other props. He runs the stock 23p Revolution that came with it.

[Rivercrazy]

Thanks Bro's. Looking forward to more opinions on this subject http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/biggrin.gif

[Essex502]

It's interesting that the boat came with a 4 blade Revolution 4 prop versus a 4 blade Bravo 1 prop.

From www.mercurymarine.com:

REVOLUTION 4
Power, speed and lift. With a Rev 4 strapped on to your V-6 outboard or sterndrive powered boat, that's exactly what you get. Its four large blade stainless steel design brings incredible traction, mind-blowing acceleration with amazing holding and top speed. Open up the throttle and go… fast.

For single or dual heavy offshore V-6 outboards, Alpha, Bravo One and TRS sterndrives
The Revolution 4 offers more bite than the Vensura
Moving from a Mirage Plus to the same pitch Revolution 4, engine RPM can drop 200 - 300 RPM
Improved planing and midrange cruising speed
R/H and L/H rotation (17"- 23" pitch)
PVS-equipped
Equipped with Flo-Torq II hub system


BRAVO I
Chances are if you have a huge-horsepower, high-performance boat, there's a Mercury Bravo I propeller driving it. That's because nothing else delivers like the four-blade stainless steel design of the Bravo I. Adding increased speed; better acceleration; and amazing, overall top-end performance; this prop leaves all others in its wake. And that is why more boat companies strap the Bravo I on their boats.

For high-horsepower, high drive height single, dual or triple outboard and sterndrive applications
Excellent speed and handling for stepped hulls and cats
Available with 1 ¼" hub kit for Bravo XZ & XR sterndrives
R/H and L/H rotation (22" - 36" pitch)
Equipped with Flo-Torq II hub system

[Rivercrazy]

What the boyz over at Shockwave told me is they deliver most of the 496 - 25 Tremors with the Rev-4 prop. They said it works better overall.

I test drove one before buying with the base 496Mag and a 22P bravo-1. It did plane faster and had more acceleration. But it didn't have the legs for top end and bumped the rev limiter a bit. Good ski wheel!

I would really like to try a 24P Bravo-1 this summer. I have a buddy that will let me borrow his. I'll report back with the results.

[KC & Karen]

Teague wrote an article in the tech section of HotBoat magazine, that essentially recommended that the 496HO be over propped due to the torque curve.

With my Nordic 28 Heat, the Bravo1 24p has significant slip coming out of the hole while the 26p has more grip, both props produce the same top speed and have good acceleration. The 26p does consume more fuel in order to get the job done, but that could be caused by my ECU – Mercruiser just replaced my ECU because of the soot on the transom and I have not had the opportunity to conduct any tests.

Essex502 and I plan to conduct some GPS testing this weekend on both of our boats as we swap props and make some runs down the lake.

[Rivercrazy]

Not sure I understand why a small pitch prop would slip more than a taller one. Â*Would it generally slip less on take off with a smaller pitch prop? Â*

I recently picked up a slightly used 21P Rev4 as a ski wheel for better take off. Â*Sounds like it might not work as good as I think!

[kevnmcd]

I think that since the 26 takes a bigger bite of the water and the 496 has the torque to turn it, that that is why there is less slip. Just my uneducated guess, though. http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/wink.gif

[Rivercrazy]

That makes a lot of sense. In other words if a prop is too small on pitch, the engine torque can overpower it?

[Essex502]

As KC said...we'll be trying a couple of props this weekend...look for BIG numbers due to the cool weather! http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/biggrin.gif

[kevnmcd]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Essex502 @ Feb. 11 2004, 1:44 pm)</td></tr><tr><td id="QUOTE">As KC said...we'll be trying a couple of props this weekend...look for BIG numbers due to the cool weather! Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/biggrin.gif[/QUOTE]<span id='postcolor'>
http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif

[Essex502]

Come on down, amigo...let's see what you all can do! Side by side...no lame excuses like: "My wife will kill me if I go over 30 MPH." http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif

[KC & Karen]

Kevin, I think the Essex502 will turn a 26p and pass your arse like it is sitting still.

[kevnmcd]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (KC &amp; Karen @ Feb. 12 2004, 08:29 am)</td></tr><tr><td id="QUOTE">Kevin, I think the Essex502 will turn a 26p and pass your arse like it is sitting still.[/QUOTE]<span id='postcolor'>
Maybe so, but we won't be finding out this weekend! http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/tounge.gif

[kevnmcd]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Essex502 @ Feb. 12 2004, 07:17 am)</td></tr><tr><td id="QUOTE">Come on down, amigo...let's see what you all can do! Side by side...no lame excuses like: "My wife will kill me if I go over 30 MPH." Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif[/QUOTE]<span id='postcolor'>
Can't make it out this weekend....but I will be making a run to either Catalina or up the coast to Long Beach. http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/tounge.gif

[KC & Karen]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (kevnmcd @ Feb. 12 2004, 10:20 am)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Essex502 @ Feb. 12 2004, 07:17 am)</td></tr><tr><td id="QUOTE">Come on down, amigo...let's see what you all can do! Side by side...no lame excuses like: "My wife will kill me if I go over 30 MPH." Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif[/QUOTE]<span id='postcolor'>
Can't make it out this weekend....but I will be making a run to either Catalina or up the coast to Long Beach. Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/tounge.gif[/QUOTE]<span id='postcolor'>
Should be beautiful this weekend along the coast!

[kevnmcd]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (KC &amp; Karen @ Feb. 12 2004, 10:28 am)</td></tr><tr><td id="QUOTE">Should be beautiful this weekend along the coast![/QUOTE]<span id='postcolor'>
That it should. I will take some pics and post them. http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/biggrin.gif You do the same...I am missing all the desert land out there. http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/smile.gif

[Essex502]

Desert is beautiful this time of year...temperatures are enjoyable.

[PUMP 'HER']

Hope this wind calms down for you guys. Looking for 15-25 mph winds Friday (reported from Needles), didn't say for Sta. or Sun. Good luck.

[KC_Nelson]

This is the link to the article:

Tech (http://www.powerboatmagazine.com/teague/archives/2003/08.php)

[Essex502]

Interesting!

[Music to my Ears]

Thanks KC. Very interesting. http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/cool.gif

[beer hunter]

I read in the most recent Powerboat Magazine (Teague on Tech section) that a guy with twin small blocks in a 27' Formula (I believe) with 21" Merc Rev 4s was running in the 70mph range. Bob Teague said something to the affect that he had seen in some situations that the 23" Rev 4 had actually given higher top speeds than Bravo 26" and 28" wheels (didn't mention the boat). I think the point with the Rev 4 is it can't really be compared to other props with the same pitch. It may have more "cup" or just slip less than a comparable pitch Bravo prop http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/smile.gif

The best top speed I have seen with my boat was 71.5 gps on a cool March morning with 3/8th gas and a VERY light load http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/biggrin.gif

[beer hunter]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (beer hunter @ Feb. 24 2004, 08:05 am)</td></tr><tr><td id="QUOTE">The best top speed I have seen with my boat was 71.5 gps on a cool March morning with 3/8th gas and a VERY light load http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/biggrin.gif[/QUOTE]<span id='postcolor'>
Oh, I also had the bow snap cover on too http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/smile.gif

[Essex502]

How about a tail wind and downhill as well? http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif

[beer hunter]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Essex502 @ Feb. 24 2004, 09:03 am)</td></tr><tr><td id="QUOTE">How about a tail wind and downhill as well? Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif[/QUOTE]<span id='postcolor'>
LMAO http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif .......No, that's a honest number http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/biggrin.gif

[Essex502]

What's the weight of your boat, dry?

[beer hunter]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Essex502 @ Feb. 24 2004, 09:09 am)</td></tr><tr><td id="QUOTE">What's the weight of your boat, dry?[/QUOTE]<span id='postcolor'>
I'm guessing about 4,400 to 4,500 lbs http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/smile.gif

[Rivercrazy]

Hey BH. Looks like our boats run pretty close overall. Now if I dumped all my stereo gear and wiring, maybe I could keep up with you! http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/biggrin.gif

[beer hunter]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Rivercrazy @ Feb. 24 2004, 1:38 pm)</td></tr><tr><td id="QUOTE">Hey BH. Â*Looks like our boats run pretty close overall. Â*Now if I dumped all my stereo gear and wiring, maybe I could keep up with you! Â* http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/biggrin.gif[/QUOTE]<span id='postcolor'>
I saw that number once, I'm sure you would have been running away from me under the same conditions http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/wink.gif I do see 68 or 69 mph on a regular basis though http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/smile.gif

[Rivercrazy]

I see the same top speeds with the Rev-4 on most days. What do you see on GPS at 4K rpm with that prop? I usually see 55-56 with a modest load. The thing I really like about the 25P Mirage Plus is I see 60 on GPS at that rpm.

[Wild Hair]

RC- You might consider a Hydromotive 4 blade.
I ran a similar setup and the Hydromotive allowed the same top speed as my 3-blade Mirage but the handling of the Bravo.

[beer hunter]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Rivercrazy @ Feb. 25 2004, 09:15 am)</td></tr><tr><td id="QUOTE">What do you see on GPS at 4K rpm with that prop? Â*I usually see 55-56 with a modest load. Â*The thing I really like about the 25P Mirage Plus is I see 60 on GPS at that rpm.[/QUOTE]<span id='postcolor'>
To be honest RC, I can't really remember http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/confused.gif Â*I do know that my optimum cruising speed (at least at Lake Powell) is about 43 mph @ 3200/3300 rpm. This # gives me the best speed to rpm ratio and the boat will comfortably run that speed in nearly any water conditions http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/smile.gif

[Rude]

from what i've been told, a boats best/most efficient speed is about 1500-1800 below it's rated WOT rpm. so in theory my boat should be most efficient at about 3400-3700. i'd like to find a way to actually measure the true fuel consumption at different rpm's.

[kevnmcd]

My boat handles best at WOT (5200) ! http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif

[Essex502]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (rude235 @ Feb. 25 2004, 8:27 pm)</td></tr><tr><td id="QUOTE">from what i've been told, a boats best/most efficient speed is about 1500-1800 below it's rated WOT rpm. Â*so in theory my boat should be most efficient at about 3400-3700. Â*i'd like to find a way to actually measure the true fuel consumption at different rpm's.[/QUOTE]<span id='postcolor'>
You just need to get a fuel flow meter and connect it inline with the fuel line...no big deal. But...do you really care? 1.5 MPG versus 1.75 MPG? http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif

[kevnmcd]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Essex502 @ Feb. 26 2004, 06:36 am)</td></tr><tr><td id="QUOTE">But...do you really care? 1.5 MPG versus 1.75 MPG?[/QUOTE]<span id='postcolor'>
NO!! If we did we wouldn't have boats....everyone knows that boat suck on gas mileage! You can basically count on this.....more hp = less mpg! http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/cool.gif

[Rude]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (kevnmcd @ Feb. 25 2004, 8:31 pm)</td></tr><tr><td id="QUOTE">My boat handles best at WOT (5200) ! Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif[/QUOTE]<span id='postcolor'>
http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif

[kevnmcd]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (rude235 @ Feb. 26 2004, 8:17 pm)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (kevnmcd @ Feb. 25 2004, 8:31 pm)</td></tr><tr><td id="QUOTE">My boat handles best at WOT (5200) ! Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif[/QUOTE]<span id='postcolor'>
http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif Â*http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/laugh.gif[/QUOTE]<span id='postcolor'>
Maybe that's not where it handles the best....but that's where I like it! http://www.lasvegashotboats.com/iB_html/non-cgi/emoticons/biggrin.gif