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James Kain.
Hey guys, I do quite a bit of fishing at lake Erie, and have a problem. I have a 2001 pantera iii with a 2006 mercury optimax and a mercury trophy 25p 3-blade prop. The problem I have is cavitation while in the main lake. I have to constantly pump the gas peddle to keep going when the waves are over 3 or 4ft. Every time I go over a wave at slow speeds it cavitates. Any suggestions? I was looking at getting a hydrofoil, or a 4 blade prop?
Lower the motor in bigger waves (jack plate). BTW, this is really called ventilation, not cavitation. Cavitation is something different where the pressure is so low on the leading edge of the prop that gas bubbles form from evaporating water, then they collapse back as they exit the low pressure. Submarines and Navy ships worry about this because it is audible. You are just sucking air into the prop rather than water. In any case, do whatever it takes to keep the prop in the water. Slow down. Lower the motor. Trim in. Etc.Sounds like you are falling over the top of the wave, which pulls the motor/prop out of the water. You might try a shallower angle to reduce that. IE instead of taking a wave at 60 degrees, take it at 45, or even 30 degrees so that pop over is not so dramatic.Last edited by oldtimer57 on January 15th, 2017, 1:40 am, edited 2 times in total.2008 Pantera Classic2014 Mercury Pro XS 200
Thank you for the correction. The jack plate isnt an option since it is manual, but when when going slow it will still happen. Would a hydrofoil help keep it down?
Lower the engine as stated above. A 4 blade prop or Fury prop will hold better than your 3 blade prop which I assume is a Tempest and not a Trophy. Trophy props are 4 bladed props.
As stated before I would try lowering the motor as it is not too hard with a manual plate, just mark it before starting. I have been running the 2001 PIII Optimax combo for years (coincidentally I am also running a 2006) , and have tried many props and engine heights over the 16 years I have owned the boat and have found that motor height makes a big difference on how the boat handles in bigger water, along with not being trimmed out to much. I run a 25 Fury 3 blade in almost all conditions, except for pulling skiers where a 24 High Five excels. The Fury prop likes to run a little deeper than most 3 or 4 blade props, and also it does not like to be trimmed out to much but still give excellent acceleration and hole shot.
You are the epitome of “why do I need a hydraulic jack plate?” This is not always a one size fits all. I live in the south and 2 waves are the most I intentionally deal with. Ive been caught out in worse, but it is not my choice. And I know that my current setup is NOT going to be ideal for 4-6 foot waves, not even close. General rule here is the slicker the water, the higher you can raise the motor and the faster you can go, up to a limit. And the inverse also, the rougher the water, the lower you want the motor so that the waves dont ventilate the prop.The electric guys have it all over us when conditions vary this much. Ventilation is hard on the motor. Revs up. The prop is spinning freely, something the gear train is NOT set up to handle, letting the gears rattle/bang against each other along with the clutch dogs. Bottom line is it needs to stay in the water, in order to stay out of your wallet. If I were going to run in the great lakes regularly, Id almost certainly bite the bullet and buy a hydraulic jack plate. If I were going to run in the North Sea, I would try to buy a US destroyer. BTW, I dont think a hydrofoil will help. It is not going to be able to hold the motor down in the water when the bow is levering the rear end out. Just introducing more stress on your transom, motor mounting bracket and motor lower unit. I have seen anti-cavitation plates (ought to be called anti-ventilation plates but thats another discussion) ripped right off of a motor by a foil.Last edited by oldtimer57 on January 15th, 2017, 2:54 am, edited 1 time in total.2008 Pantera Classic2014 Mercury Pro XS 200
I will raise or lower my manual jackplate while on the trailer before launching depending on the weather conditions expected. My Slidemaster only needs a 3/4″ and 1 1/8″ socket or wrench to make any adjustment. I go by my pre-determined marks on my jackplate for high and low settings (only about 3/4″ between the lowest I run the Fury to the highest). I even have 1 really high mark that I used a few years ago when running a 26 Tempest or 26 Trophy for max speed as both of those props liked being run very high.
Hey James , Ive spent my entire life on erie and st. clair , although in a cougar now and did experience the exact same conditions when I run my 3 blade tempest prop . Went to a 4 blade trophy and it cured the problem . Whether it was the extra bite from the trophy or the smaller diameter that keeps the prop tips a little deeper in the water I dont know but works for me . Does give up a little top end over the tempest but usually cant use it on the big water anyway .
Thank you guys so much, I think I might try out a 4 blade and then maybe lowering the motor. I also have a slidemaster jack plate.
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