Slow to plane.

My Robalo 2120 w/ 200 Merc is slow to get on plane. Motor winds out slowly w/ high bow angle even when fully trimed in. Not running any trim tabs or cavitation plate foil. Hull is extream deep V (22 degree rise) and weighs in at 4400 lbs +/_. When its wound up with the motor trimmed out some, she'll do 42mph at WOT/ 5000 RPM. Current prop is 3 blade SS with 19P.

Not looking for a bass boat hole shot (lake freightors are slow anyhow) but would like to get on plane sooner. Never in a big hurry, so willing to give up a little of the 42 mph's.

A "vented" prop was suggested once.

Re: Slow to plane.

42 sounds pretty good, but the RPM is low. You should probably be able to maintain the speed and get better hole shot with a 17. 5000 RPM is right at the bottom of the range, so you have some room to go down assuming this a 2 stroke . . . Vents help too, but wouldn't help your WOT RPM, so I'd go down first, and then add vents if the 17 doesn't work as well as you hoped. Also, you need a spare anyway, so that's what the 19 is for . . .

Re: Slow to plane.

i agree... a 17p ss prop would probably be great on your boat. shouldnt lose top speed, it will just be at higher rpms

Re: Slow to plane.

QC and MPSYAMAHA,
Thanks for the advice, I'll look into a 17.
One further question, what is the significance of going from 3 blades to 4?
Most explainations I've read talk about vague concepts such as "hole shots" etc, etc. It would seem to me that for a given RPM 4 blades would have to move more water than a 3 blade at the same pitch and dia. but at the cost of additional energy (more throttle) at the prop shaft. If one is pegged out on the throttle on accelertion to a plane, would not the 4 blade bog the engine more so than a 3 blade??:

Re: Slow to plane.

QC
Thanks for the advice, I'll look into a 17.
One further question, what is the significance of going from 3 blades to 4?
Most explainations I've read talk about vague concepts such as "hole shots" etc, etc. It would seem to me that for a given RPM 4 blades would have to move more water than a 3 blade at the same pitch and dia. but at the cost of additional energy (more throttle) at the prop shaft. If one is pegged out on the throttle on accelertion to a plane, would not the 4 blade bog the engine more so than a 3 blade??:

Re: Slow to plane.

I think the 4-blade has more "grip" out of the hole with heavy throttle. It may have more drag at top end which is why less top end speed. The tiny increase in drag isn't significant compared to hauling your heavy boat from a dead stop.

Smart tabs and a 17" prop (or maybe a 16" 4-blade) might really change your boat. I had similar issues and put the Smart tabs on last year - they helped on take off a lot to keep the bow down. I repowered during the off season and am now looking for a new prop. I've heard great things about the Stiletto Bay Pro II 4-blade SS for heavy boats in this hp range. I'll be buying one soon. Do a search for "Bay Pro" if interested.

Good luck.