I need help Getting On Plane Please!!

[bigpikeguy]

Ok i have a 2009 G3 Eagle 165 with a yamaha F20 4-stroke powereing it. I am limited to the 20HP because In PA most of our lakes have a 20HP limit. I am so close to getting on plane its sickning. I started out with a 9 pitch alum prop from the dealer and that did not seem to cut the cake after it was broke in. So i swaped for an 8 pitch. that seemed to raise my RPM's but not really move me any faster. Then i bought a 8 pitch stainless prop that will get me on plain by myself but with 2 guys in the boat it wont. the thing is it will over rev once it gets on plane so i got to keep an eye on my tac so i dont blow up the motor. this is how close i am to getting on plane with 2 guys, if i run the boat in shallow water wide open with 2 guys in the boat it will get onto plane and start to over rev, but the minute i get into deeper water the rear end on the boat sinks back down again. im running about 10mph wiht 2 guys and once it gets on plain the speed climbs to about 15 i would say. my RPM's are at about 5400 sometimes 5500. Once i get on plain it wants to go over the recomended WOT of 6000. With a 9 alum by myself i had the boat planeing and running around 20mph with the speedometer, not sure how accurate they are lol. with that being said it really dogged with the 9 pitch wiht 2 guys hardly hitting 5000 rpm.

I already tried a foil on the back with no success. That worked on my other baot so i had high hopes. I was thinking of smart tabs but i really dont wanna drill if i dont need to. As of now i am in the process of moveing one of my batteries out of the back of the boat to front of the boat on the passenger side storage compartment in hopes that it will get some of the weight out of the rear. Right now i have 2 batteries and my fuel tank back there and i think that is why the rear end is sunk in the water at WOT. I dont fill my tank no more than 1/4 full due to the fact that i dont really need to since for one the 20hp is not hard on gas and i really dont need the extra weight. if that fix dont do the trick i dont know what will, im out of ideas. the fustrating part is how close it is to getting on plane. I think if this fix works i should be able to jump up to a 9 pitch stainless to fix the over reving problem and hopefully it will still get on plane??? i hope, but if not i will just have to keep an eye on my tac to make sure it stays below 6000 with the 8 pitch.

 

[QC]

Re: I need help Getting On Plane Please!!

Welcome aboard bigpike!! I have moved this over to the general Boat Topics section. Not really an engine issue and there is a lot of help for this type of issue over here. Good luck!

 

[QC]

Re: I need help Getting On Plane Please!!

I think I have this figured out . . . Get over the aversion to holes

If you are this close, tabs will solve it and you may be able to go to 9 inches of pitch. Look how frustrated you are; add in all that you are trying to solve the issue. Then compare that to the fact the solution is already known, and the methods for install are understood including sealing the holes. My .02.

 

[Bondo]

Re: I need help Getting On Plane Please!!

Ayuh,... Have you changed the angle of attack on the motor,..??
Raise it Up,..?? Drop it down,..??

 

[bigpikeguy]

Re: I need help Getting On Plane Please!!

The reason i did not do the tabs 1st is because i talked to a dealer 1st and he said since im so close, try everyhting else first before i go drilling holes in my boat. He said moving the batteries around my be all i need. Pluss doing all this other stuff first may save me money lol. The tabs im looking at are around 150.00. not a ton but hey if i can save it i will. My consern with them is that maybe they wont fully compress and will cause drag + if they dont work i just scored a few more holes in my boat.

No i have not played wiht my motor height at all yet. However i was thinking about pulling the stop pin and moving it back a hole so maybe i can get the motor to push the rear end of the boat out of the water? any think else i could try??

 

[JimS123]

Re: I need help Getting On Plane Please!!

I looked up the specs for the boat. The max HP is 60, and the smallest factory offering is a 25! They don't list weight, but I would guess its pretty heavy. IMHO you just don't have enough HP to get the job done.

I understand your dilemma about 20 hp. If it were me I would have settled with a 16' Starcraft utility with a floor. They weigh considerably less.

Sounds like your "dealer" should share some of the blame because he sold you the rig with a 20. He should have known better.

I wish I had a suggestion. I'm surprised the fin didn't help.

 

[GXL205 Deke]

Re: I need help Getting On Plane Please!!

Nauticas Smart Tabs

 

[ovrrdrive]

Re: I need help Getting On Plane Please!!

The whole "planes in shallow water but not in deeper water" also makes me want to say a set of tabs would most likely do it for you. The extra stern lift they'll give you would mimick the shallow water lift.

Any chance of putting a 20hp cowling on a bigger motor?

 

[Moody Blue]

Re: I need help Getting On Plane Please!!

if i run the boat in shallow water wide open with 2 guys in the boat it will get onto plane and start to over rev, but the minute i get into deeper water the rear end on the boat sinks back down again.

I don't see how that's possible. Its like saying you can run across shallow water but will sink if you try running across deep water. Depth of water plays no role in whether a boat will plane or not.

As others have suggested, minimize weight, distribute load, optimize trim angle of motor, install trim tabs and keep the wind at your back.

 

[grego]

Re: I need help Getting On Plane Please!!

sand bags seem to be everywhere these days, get a few and add to the nose of boat. You are not useing a lot of hp. soooo! you need to distribute weight around boat to help with planeing. Makes NO sence that it " planes in shallows, not in deeper water". If you are cavitating your prop and overreving your engine, then you may need to drill. Seems to me that boat and motor, should be setup from manufacterer. I feel that 20 hp motor and planeing,is seldom used in the same sentence.

 

[Black as]

Re: I need help Getting On Plane Please!!

o.k. a really silly question here, how much do you and your friends weigh

 

[smokeonthewater]

Re: I need help Getting On Plane Please!!

it makes PERFECT sense to plain in shallow water.... planing is flying and with an airplane it's called ground effect....

If you haven't played with the engine trim then hold the phone... that is the absolutely first thing to try.... and retry after any other change

Also go through the whole boat and look for anything you can remove to save weight


A thinner head gasket .... slight timing advance... smoothing intake tract maybe a bigger carb .... can make a little more power.. thinner head gasket and timing advance are good ones but will require higher octane

Also Lucas synthetic 100:1 premix makes more power because you are burning less oil and lets you lean out the carb a little more


clean waxed hull makes less drag....

 

[grego]

Re: I need help Getting On Plane Please!!

wieght "matters not". Placement of wieght means everything! personaly, i wound not drill. the boat and engine "SHOULD!" be setup to maximize it's abbility to move on water. to change it, should only cause you grief trying to improve on factory specks. my 02.

 

[bruceb58]

Re: I need help Getting On Plane Please!!

I agree with getting weight forward. That is your best chance of getting on plane. As far as how it performs in shallow water, not sure it really matters why...more than likely just the thrust that is hitting the bottom.

 

[cr2k]

Re: I need help Getting On Plane Please!!

Planing is flying? Ground effect? What did you miss some science classes?

The ground effect you speak of is the air compressing under the flying surface increasing the atmospheric pressure.

Last I heard (and I still think it's true) water does not compress. This would explain why it causes so much destruction when it gets in a cylinder. (unlike air)

Check your engine. depending on brand and HP it may be easy to raise it 25 or 30 with a carb change. Some engines are basically the same except for tune and carb or head. like the older john/rude 9.9-15 or the Yamaha 200-225s

 

[Home Cookin']

Re: I need help Getting On Plane Please!!

Running over shallow water is an old waterman's trick we do all the time on the Eastern Shore. The water compressing under the hull lifts the boat. However, pnce on a plane, it maintains when you move to deeper water--unless you are underpowered.

you are underpowered. Plane and simple. It's hard to plane a lot of boats at 10-15 mph. The fact that you plane alone and not with three people confirms it.
Tabs might work, might not--but they will cost you. I often question putting them on a boat that small, but people do.
If the law restricts you to 20 HP then getting a bigger motor with a "smaller" cowl would be illegal. Not the crime of the century, though. same probably goes with bumping up the carbs-and that may cost as much as tabs. Less than a new motor and a "smaller" cowl.
Frankly, I think you are wasting a lot of time and money trying to make it work. It's like trying to soup up your Honda civic so you can tow your 24' boat. Put your 20 on a 14' wide body Lowe.

 

[bigpikeguy]

Re: I need help Getting On Plane Please!!

Thanks guys im taking in all the advice you guy are giving me. I understand why by boat is planeing in the shallow water, and thats why i think trim tabs may work. I just looked at cabelas and the smart tabs there are $130.00 and those are the ones that i am thinking about getting if it comes down to it. My problem is the trim tabs rateings. The smallest ones are for a 12' to 15' boat with a 25 to 35 HP motor. the next ones up are for a 14' to 17' boat with a 40 to 80 HP motor. Im not sure which ones to get? keep in mind my boat is 16.5' long. the way i understand it is the only difference is the amount of force to compress the actuators not the size of the tabs. One may be 30lbs the other may be 50. Im thinking the smaller ones would be the better bet just do to the fact my boat has a smaller HP. As for the question about my weight i am 6'1" 230lbs and my wife is 5'7" 130lbs. it only takes 130lbs to make me not plane . Still it is so close.

As for tinkering with the moter i have thought of that. Im good at working on stuff like that. I was gonna polish my ports on the motor and see if that helped me out at all. But im gonna hold off on that for now and explore my other options just due to the fact that i have a 6 year warrenty and i dont think yamaha would like me doing things like that lol. As for a carb swap in not sure if yamaha's F25 carb would work on my F20. The F25 motor looks huge so i think is is a compleatly different power head. So i think the carb swap may be out of the question but i will look into it.

Tonight i am finishing up My batterie move and i am going to test the boat out on friday to see if that helped at all. I got my fingers crossed. If that makes and difference and i still dont plane i will probably try to raise my motor a little bit and see if that helps. will keep all of you posted on what happens. Untill then if you have any more ideas please let me know.

 

[bear_69cuda]

Re: I need help Getting On Plane Please!!

Smart Tabs, and carb tweak should do the trick..

 

[smokeonthewater]

Re: I need help Getting On Plane Please!!

Planing is flying? Ground effect? What did you miss some science classes?

The ground effect you speak of is the air compressing under the flying surface increasing the atmospheric pressure.

Last I heard (and I still think it's true) water does not compress. This would explain why it causes so much destruction when it gets in a cylinder. (unlike air)

Check your engine. depending on brand and HP it may be easy to raise it 25 or 30 with a carb change. Some engines are basically the same except for tune and carb or head. like the older john/rude 9.9-15 or the Yamaha 200-225s

Nope didn't miss any class and don't care to debate all the little details but wanted to simplify for those who have less than a complete grasp of fluid dynamics..... ground effect is a bit more complicated than "air compressing under the flying surface".... from wikipedia"Flying close to a surface increases air pressure on the lower wing surface (the ram or cushion effect) and decreases air acceleration so the ground effect improves the aircraft lift to drag ratios in two ways. Momentum is still balanced because the air pressure beneath the wing is pressing on the underlying surface." The same effect here happens in water.... perfect example I can ride a dirtbike at high speed forever in 2-3 feet of water with the skid plate skimming the surface.... try to head into deep water and it will sink...

My main point though was that it is VERY possible that a boat could plane in shallow water but fall off in deep water

You are right it isn't actually flying because in a boat you are topping one fluid and staying under another and indeed the effect is a little different.... what i should have said is that it is SIMILAR to ground effect... not to be confused with WIG which is another related principal

Now NONE of that matters here..... so the best I can offer here id minimize weight, distribute weight, minimize drag, and maximize power.... smooth any burs on the prop look for anything that could slow you down..... It's amazing how a bunch of little things can add up....

 

[bigpikeguy]

Re: I need help Getting On Plane Please!!

What do mean when you say carb tweak? Is there something i may be able to do with my current carb? or did u simply mean to swap it out???