Jack Plate

[VIP]

Have a question to those that have jack plates.

I have a 17' fiberglass w/Yamaha 115 (4 stroke). At 45mph it starts porpusing when I trim it out, and that is the top speed I can go. Would a jack plate help this? I have moved weight around (ie..sand bags, batteries, etc..). I already tried the hydrofoil gimmick, it killed my out of the hole time, and did nothing for top end. Is this the top speed for this HP or should it go faster.

On a side note; there was a guy about a month ago or so, that had a tourney boat for sale. Anyone remember the details about it? A friend is looking for a newer(95 or newer) boat w/4 stroke for around 10k or so. Anyone know of one?

[Trevor K]

There is still a boat for sale in the buy/sell/trade section of the forum right now, but I don't think you'll get it for $10k

[shaker]

VIP I had hoped that you would get some replys on this. I have same issues with a 18' aluminum boat with a 90 E-TEC, couldn't get any help from the dealer. Finally moved the trolling motor batteries to the front of the boat along with everything else that I could get there, tackle boxes and cooler. This helped somewhat but didn't totally fix the problem. I finally called the manufacture and talked to a teck, he said to bend the trim tabs down at the back of the boat, which I had already done then he said bend them some more, which I did now they are bent down at a almost 90* angle, which helped a bit more. I called back and ask about adding a jack plate, he told me "DO NOT PUT A JACK PLATE" on that boat. Wouldn't give me a reason why, I suspeck that they had never tested that setup with a jack plate and didn't want any liability issues, just my guess. I don't see where a jack plate could do anything but help, but don't know, I have ask the same questions on several forums and ask a number of people the same and have never gotten any answer, I hope you find a solution to your problem if you do I would appreciate hearing how you fixed it. Good Luck!

[VIP]

VIP I had hoped that you would get some replys on this. I have same issues with a 18' aluminum boat with a 90 E-TEC, couldn't get any help from the dealer. Finally moved the trolling motor batteries to the front of the boat along with everything else that I could get there, tackle boxes and cooler. This helped somewhat but didn't totally fix the problem. I finally called the manufacture and talked to a teck, he said to bend the trim tabs down at the back of the boat, which I had already done then he said bend them some more, which I did now they are bent down at a almost 90* angle, which helped a bit more. I called back and ask about adding a jack plate, he told me "DO NOT PUT A JACK PLATE" on that boat. Wouldn't give me a reason why, I suspeck that they had never tested that setup with a jack plate and didn't want any liability issues, just my guess. I don't see where a jack plate could do anything but help, but don't know, I have ask the same questions on several forums and ask a number of people the same and have never gotten any answer, I hope you find a solution to your problem if you do I would appreciate hearing how you fixed it. Good Luck!

Me too Shaker. I have added sand bags in 25lbs intervals up to 150lbs and no joy. It actually got worse. it goes faster with no weight up front. I'll buy one next spring and give it a shot. I was hoping someone here would have knowledge about it so I wouldn't have to spend the $$$ not knowing if it would help. If I remember, I'll let you know.

[fishinwrench]

Adding weight to the front of the boat is going the wrong direction if you are trying to eliminate excessive porposing. What you want is a LIGHTER front end, not heavier. Porposing is caused when the motor is trying to lift the bow....but can't quite keep it lifted, it is doing a juggling act between plane and plow.

Engine height on the transom, trim angle, prop bite, and raw torque (in that order) are how you diagnose porposing problems.

If you also blow out on sharp turns you may need to drop the engine 1 hole, which will probably cure both the blow out problem AND the porposing.

If it doesn't blow out on turns BUT the only trim angle you can maintain (without porposing) is one that causes the boat to plow, then you either need a better bite at the prop, OR MORE HORSEPOWER. You can have a good prop shop add a bit of cup (lift) to the blades, that will noticably help.

Hydrofoils (IMO) are just a crutch to compensate for poor rigging. And much the same can be said for jackplates.

A properly rigged 115 (turning 5500 rpm) should push you darn close to 50 mph in ANY 17ft. bassboat.

[shaker]

Thank you fishingwrench, thats more info than I have seen in two years of asking. I think that I will try moving the batteries and charger back this winter and work on this some more. I have been up and down with the motor, I am maxed out with horsepower and pitch right now I am running a 18' aluminum boat with a 10* hull, 90HP E-TEC with a 18" stainless prop turning 5000 rpm runs 40mph, handling is less than desireable. One thing I wonder about this is a heavy boat (1200# hull) for aluminum and very wide 90" beam does this come into play? Again thanks very much the help is appreciated.

[mosouthpaw]

head over to http://bassboatcentral.com/ and find the setup by todd forum. those guys will get you set up and get your boat running well.

[VIP]

Adding weight to the front of the boat is going the wrong direction if you are trying to eliminate excessive porposing. What you want is a LIGHTER front end, not heavier. Porposing is caused when the motor is trying to lift the bow....but can't quite keep it lifted, it is doing a juggling act between plane and plow.

Engine height on the transom, trim angle, prop bite, and raw torque (in that order) are how you diagnose porposing problems.

If you also blow out on sharp turns you may need to drop the engine 1 hole, which will probably cure both the blow out problem AND the porposing.

If it doesn't blow out on turns BUT the only trim angle you can maintain (without porposing) is one that causes the boat to plow, then you either need a better bite at the prop, OR MORE HORSEPOWER. You can have a good prop shop add a bit of cup (lift) to the blades, that will noticably help.

Hydrofoils (IMO) are just a crutch to compensate for poor rigging. And much the same can be said for jackplates.

A properly rigged 115 (turning 5500 rpm) should push you darn close to 50 mph in ANY 17ft. bassboat.

Thanks Fishinwrench. When I pulled the weight out, I also added 2 batteries in the back just by luck. This is when it picked up 5mph. I'm running 45mph @ 6000rpm with no rooster tail. The engine is as low as it'll go now, prop bite I have no idea. I've tried the local marina that installed the motor, but they aren't interested in helping. Turning is not a problem.

The front is as light as it is going to get now, so I'll try moving the motor on the transom, and see what happens. Thank again for your help.

[skeeter]

Agree with everything fishin wrench posted. I'm assuming you are running a stainless prop ?

Having owned and driven high performance bass boats since the early 70's ( well, they weren't really high performance back then ) I would concentrate on your prop at this point.

I haven't used a custom prop shop in several years so don't know who is doing what but I would suggest taking your rig to a recommended shop that is on or very close to the water. Tell them your problem, be prepared to spend a few bucks and turn them loose on the prop and ask them to test it on the water after modifying the prop. You may get away with just buying a different prop or they may need to install a different prop and then put some "cup" into it. A good custom prop bender will get your boat maxed out and running the way you want it to. I'm guessing with your report of no rooster tail that you need a prop giving you more "lift" at the stern of the boat when you are trimmed out especially since you are running a four stroke as they are heavier than a two stroke of the same HP.

Happy and safe boating.....

[Ämp]

all that money and you only do 45?.. my lands you need to at least get 80 or your not bass fishing!...