Is it common for a Hydro q4x prop to drop the bow when mashing the throttle at mid range? Mine still do even with 1/2" removed of the Hydros flare. Would removing more flare help? Do over hub props do the same thing, I have run a few but wasn't looking for that at the time.
X-OB or X-OT? I once ran an X-OB with welded on ring (flare) and it was not the right prop for my hull. The large barrel and the flare would throw the stern up quickly (good for hole shot) however as you know, when the stern goes up, the bow goes down and thats a recipe for disaster with an Allison. I should add that I was running 1:75 gears back then.
With the 1:62 gears, I much prefer the smaller barrel of the X-OT as well as over the hub props such as Chopper, Mazco RE's, etc.
Dont know if this helps you or not but this has been my experience with the bow dropping with the flared large barrel props.
Dean, is it dropping the bow or driving it down cause the prop is hooking up and ya need to trim back up??
I have several props that if I'm just cruising with the motor low and I stab it they push the bow down till I bump the trim and plate up..
Both my Bravo 1's do that (and both have the tubes cut x 3/8") and so does my bullet cut original Raker 28P. My Performer P4 does not drop like that, but it doesn't feel like it's hooked up as well either.
2019 Allison XB-21 / 300R
Musky Fishing Machine
I would think it is slamming the nose down because of neg trim that is what mine does but it will pick it back up after some of the speed catches up with the acceleration
I agree with Kurt on this one........my 30p Hydro likes to plow at mid range until I bump the plate and trim...it likes that sweet spot....it is a lot better since Croxton re-worked it...still a very good load carrying prop
STROKER BOATS & MERCURY RACING
Talk the Talk..and Walk the Walk
I was playhing last weekend when I noticed it. Motor 2" above pad, smartcraft trim gage on 6 (about a 2 degree pos trim) crusing about 4500-5000 rpm. I think it is driving the nose down because it does come back up with more pos trim, it will also lift with more speed. Currently running 13.5" set back. I will play some more this weekend at diff speeds to see what happens.
Dean: One observation that I think is relative to your specific high altitude. Assuming both our smart craft gauges would sync in for trim position I never have run more than 4.2 for positive trim and 6 would be way over trimmed for me so IMHO A) You have some negative tuck in your extension plate system or B) That high altitude running makes you need more positive trim to hold the bow at proper running angles
This is just my guess, not sure it helps with your question but I've never experienced the type of altitude running you do so it's very eye catching to see you running such a smart craft position to me.
every boat and every gauge will vary
especially if you dont have one....you guys are to high tech
STROKER BOATS & MERCURY RACING
Talk the Talk..and Walk the Walk
Water density change at higher altitudes is statistically insignificant. Water is a very constant viscosity. Saltwater is a higher density and can affect it, but not altitude.
Eli, if I run with less pos trim, I get what I call high speed porpus (sp?). When stretching it out I will usually end up with the engine 3"above and pos trim around 6.5. I usually keep playing with heigth and trim during a run until I run out of space. We'll see what this weekend brings.
air lift will change at elevation
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stroker300x »</TD></TR><TR><TD CLASS="quote"> air lift will change at elevation</TD></TR></TABLE>
for sure!!
On the smart craft gage and trim issue, I can only go by the monitor I'm using, I set it up and calibrated like in the manual so it compensates for my 3 degrees of extra tuck. I'm also around 4 to 4.5 for a trim #er..
Don't sound like your over trimming due to the fact you have to trim out of the "stern lift porpoise"
i think its normal once the boat starts lifting and you mash the gas the dropping bow usually doesnt happen any more...I have had some props high porpose... some dont...some really bad some you cant make it porpose...I think some props have too much lift built in and its really not needed on a stroker..... the hull it self does alot of lifting
one thing about a stroker if you bump up the trim and it goes faster, it wasnt trimed high enough....if you bump the trim up and it slows down, over trimed.....same with the plate...the boat will give you a sign .....you just have to follow it
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by STROKEDYAMAHA »</TD></TR><TR><TD CLASS="quote"> the boat will give you a sign .....you just have to follow it </TD></TR></TABLE>
You sound like Wayne Taylor. I miss him.
2019 Allison XB-21 / 300R
Musky Fishing Machine
The set back I curently run has no neg tuck built in.
The original thought about this post was about over/thru hub exhaust props and driving the bow down. That being said, I do like comparing information and I will have more after the next couple of days. I run more pos trim at elevation than I did at the 07 Stroker rally but I continually adjust to try for a bigger ###.
Dean: With your motor trimmed all the way down what does your smart craft gauge read?
As I said earlier the syncing of the gauge is an important factor when talking about a specific smart craft gauge reading.
The trim gage is zero'ed out when all the way down. When I aired it out today I actually trimmed up more that usual and then back down continually adjusting motor heigth and trim to maintain wp and wt. Ran 93.9 at 5850 rpm. I guess I just need to run at whatever trim works for me out here.
Lou, when mashing the gas, the nose does drive down but comes back up with more apeed and trim.
Wow Dean that's amazing just how much the elevation affects thingsWhen you hit your best speed do you remember what the smart craft trim was reading? Also is "wt" water temp? I assume as measured on the smart craft gauge as well?
Reply With Quote