jackplate question

[stinkbait85]

Does adding a jackplate increase the stress on the transom? It seems logical to me that it would since the leverage of the motor pulling against the transom would increase. But is it really enough to worry about? And what is the real purpose for a jackplate? Allow you to run in shallower water? Or does it just improve the handling of the boat?

 

[grego]

Re: jackplate question

actually, bolt and plate placement is better that the factory 4 stud "no ajustment" method. and yes.

 

[Capt'n Chris]

Re: jackplate question

Does adding a jackplate increase the stress on the transom? It seems logical to me that it would since the leverage of the motor pulling against the transom would increase. But is it really enough to worry about? And what is the real purpose for a jackplate? Allow you to run in shallower water? Or does it just improve the handling of the boat?

A jack plate will add some stress to the transom. Boat warranties will oftentimes address this issue and warning. The static jackplate will move your motor aft necessitating additional leverage to "pry" your boat out of the water. In essence, you have created a longer running surface. Hole shots can become more lengthy or stodgy and you may develop porpoising (which, incidentally, can most always be corrected with a prop). This, of course, is dependent upon the power you have and on what boat...so many variables and all sorts of unknowns. The only "worry" would be how well you can tolerate a change modest change in acceleration performance that you would be dealing with if you were marginally powered. The jackplate allows for infinite vertical adjustment to fine tune performance, but in conjunction with the correct prop too. It also moves the motor back into the cleaner portion of the slipstream and into the rise of the displaced water as it exits beneath your boat. By doing so, typically the motor can be run higher. Adequate cooling must be monitored should the height be excessive. I have been referring to the static properties of a jackplate. The dynamic jackplate is, of course, adjustable at the flip of a switch to adjust the height at will. Yes, lots of boaters use the hydraulic lift to run shallow and many outfit their cooling to draw adequate water when raised substantially. As for handling, if you are adequately powered, a jackplate can help increase speed somewhat. A correct prop; however, coupled with proper motor rigging (jackplate or not), is the key to obtaining your best performance and economy. I use a static jackplate and custom props with my little rig....just can't get the ole racing blood of years ago out of my system!!

 

[stinkbait85]

Re: jackplate question

Well I run in pretty shallow water and in most cases 4 feet or less. The boat is a 16 ft fisher. It has a 75 hp johnson on it. I did have a problem with porpoising at first and like you said I changed the prop and added a hydrofoil. would really like to get the motor a little higher but if I chance overheating the motor it may not be worth it. I already risk that enough running in the shallow water. I was just curious of the pros and cons. Thanks alot

 

[Capt'n Chris]

Re: jackplate question

I am not a proponent of fins or hydrofoils. I have always thought that they lull one into a false sense of correction. They have a tendency to disrupt cooling, cause unwieldy handling and can snap off an AV plate. That,s probably not what all you want to hear, but a prop will correct most any problem. Running shallow is often done, but it is also flirting with trouble.

 

[grego]

Re: jackplate question

In shallow water the jackplate is the way to go, by raising the engine you run less risk of damage from hitting stumps,laydowns, and the bottom. I love hydrolic, hate manual! there are so many useful things you can do with hydo that I would not "with a choice" use the manual.