CX20 Mercury 250 w/ 24P Bravo 1 4 Blade Prop Test

[jackdz1]

This is a first test and the data is preliminary. I have some gopro video (doesn't show speed, but I call it out) that needs editing. As a reference, my current setup is a 2021 CX20 Pro, Mercury 250 4 Stroke, 10" Atlas Hydraulic Jackplate, 24P Fury, 2 10ft Talons, 4 AGM batteries, 36v Ultrex, full tournament load of tackle (300-400 pounds), 10 hours on the motor, the port livewell was full, starboard was empty, no passenger. The holeshot with the Fury was pretty bad. I had a 24P Bravo 1 from my previous boat (21ft Ranger, Yamaha SHO) that I installed and was able to get out on a local river to test. The weather was not favorable for full out top speed as we had a 20mph sustained winds out of the south and the stretch of river runs south to north. Current was about 2 mph from south to north and there was a 2 ft chop on the water. I ran the Atlas at (lowest to highest is 0-20) 0, 2, 3, 4 and 20. The Bravo really made a difference on the holeshot, 0-40mph took less than 8 seconds and reached a max speed of 70.1mph (~5800-5900 rpm) in less than 20 seconds....there is more speed in this.... 1) the water was too unpredicatable to really wring it out, 2) this stretch of the river is too short and 3) my ability to drive the chine walk. I'm hoping to be able to do more testing this Saturday and I'm going to take the original 24P Fury and put solid plugs in the PVS to compare. The chine walk is comparable to what I experienced when running the Fury, at about the same speeds. I am open to discussion as I've owned bass boats for 35 years, but never had one that would run faster than 72mph or chine walked like this one.

[CX21]

Does the chine walk feel more like a bow roll? More than a few of us have that type of walk rather than the side to side rocking chine walk. I am able to calm the bow roll type by raising the jack plate a little and trim down a touch when it starts. Boat always has a little walk at speed, but it is totally controllable by even a novice like me. Weight balance is a bigger deal in caymas than some other boats (skeeter). I'm running Bravo1 FS 23.5p fully plugged vents on CX21. Bravo1 seems to be a great prop for all around performance, except max speed of course. Someone did a good write up on this problem on another post. Says same thing. Gotta find the sweet spot and don't bring the nose up too high. It'll start doing bow circle rolls.

[jackdz1]

I read the post on bow roll and tried the techniques discussed. It’s a more exaggerated than “roll”, and can become alarming at 71mph. Gonna play around with balancing the load. If I can get this figured out, I think I can get above 73mph with the Bravo.

[jackdz1]

I should add that I was in very shallow water (>2ft) and with the Atlas at its highest, it really got on pad quickly.

[jackdz1]

We had fairly good water to run on yesterday and I spent more time running this setup. Unlike most others, my boat lists to the starboard (drivers side) pretty severely through 40 mph. It does straighten out after that. During the test runs, I was running the jackplate at 2” up ( I use the ruler on the JP as reference due to the gauge being inconsistent) and it chine walked pretty severely. I decided to run the JP up to 4” up and had a best run of 72 mph at 5900 rpm. The chine walk was ver insignificant. Both gas tank and livewells were full. Holeshot is pretty good.