Maxxon Boat will not plane!

soggydan

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Aug 17, 2006
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1
I have an 11'9" maxxon cs360 inflatable. I have a 15 hp short shaft motor on it, which everyone says is the correct length. When i apply half power, it cavitates a little (the prop is not under water), and it never planes out. I thought maybe I need a long shaft, but everyone I call who sells the boat says no. Whats up?
 

Jdeagro

iboats.com Partner
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Jul 30, 2003
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1,682
Re: Maxxon Boat will not plane!

The antiventilation plate (sometimes refered to as cavitation plate) directly above the prop should be about even with the bottom of the boat. This will tell you if the shaft is the correct length or not.
 

studlymandingo

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Mar 22, 2006
Messages
2,716
Re: Maxxon Boat will not plane!

If it is the correct length, then it could be raised up too high on the transom. As John said the A/V plate should be about even with the bottom.

Perhaps a set of Smart Tabs would help!
 

deejaycee_2000

Captain
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Mar 28, 2006
Messages
3,447
Re: Maxxon Boat will not plane!

It sounds to me if your transom tilt lock pin is set too high, a little inflatable are not designed for a long shaft, so you simply have a setting issue ..... the anti-cavitation plate should be level with the bottom of the boat ..... set the tilt lock pin on the second hole from the transom ... and see what it does ... inflatables have the tendency to cavitate very quickly because they are so light .... so you need to lean to the front when open the throttle to plane, and as soon as it comes over to plane move to the back and there your go ...
 

shanonamous

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Jun 1, 2008
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Re: Maxxon Boat will not plane!

SoggyDan,
I have this same setup and am having the same problem. Maxxon 360 with the high pressure air floor and a 15 hp Evinrude short shaft. I used to run the boat with a 6 HP Suzuki long shaft and it worked pretty well, but was underpowered. I could get it to about 10 or 11 miles an hour and it would barely plane. I have since "upgraded" to a 15 HP Evinrude short shaft with poor results. The motor runs fine, but the boat does not work well at all. I have added a set of lifters which help a little, but not much. Without the lifters I can get it to about 12 mph, but it has a hard time planning and the prop ventilates a lot. With the lifters I can get it to about 13 mph. The boat porposes, is slow, and the motor still ventilates. Have you or anyone else out there figured out a solution to this? The lifters are not the improvement I was looking for and frankly it handled better, albeit a little slower, with the 6 HP Suzuki long shaft.
 

SnappingTurtle

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Joined
May 4, 2008
Messages
1,251
Re: Maxxon Boat will not plane!

You might want to try these ...
 

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shanonamous

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Jun 1, 2008
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Re: Maxxon Boat will not plane!

Turtle,
I tried them. Those are the "lifters" I was talking about. They help a little, but not much. I am actually pretty disapppointed after reading all of the testimonials as I have not had the dramatic results with this setup that many others claim. I have since bought a Doel Fin which I hope to try this coming weekend. It seems to me that the lifters may create an all new problem with this setup by "stuffing" the nose while providing lift in the stern, much like an over trimmed trim tab. I think this in turn may be causing excessive drag. The propeller is still not getting a clean flow of water all the time and is frequently "blowing out", but it is even worse without the lifters. Anyone else have similar problems that they have been able to remedy?
 

SnappingTurtle

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May 4, 2008
Messages
1,251
Re: Maxxon Boat will not plane!

I hate to hear that! :mad:

The lifters were a suggestion from a friend with a small Zodiac (I need to call him and tell him to hold off on his purchase).

He is having the same problem as you, and this was what he was told to install by the local dealer.

He, like you, was also told about the wonders of them, with double the top speed, better cornering, better gas mileage, faster to plane, slower plane speeds ...

... bla bla bla ...

This is the same dealer as the one who told him the motor he bought when buying the boat is more than enough for his described needs.

It won't plane with two light adults now, and will barely do it with him alone in calm water, they live on the gulf (not calm), and this was supposed to be their salt water transportation/toy). He is running a 8 or a 10hp, I forget which.

He said he didn't want the minimum power need to troll, he wanted a little speed with reserve power.

When I bought my 6hp, the man I got it from said he had it for a while on his inflatable (used as a tender and just to play), changed to a 10, then a 20, and in the end a 35hp before he was finally happy with it. All were recommended by the marina as the idea solution. Now he said it flies, but that is an expensive option. Had the marina been honest from the beginning, he said he would have bought another boat type.

Sometimes I think those earning on the sale, or those producing the product, should be the last to ask for advice. If they think you don't want to spend much they will tell you a 3HP is perfect for what you want to do, if the think you got money to burn they will tell you, you need at least a 300HP. :mad:

Keep us posted on the progress and any solution you find, I have a friend in Florida who will be happy to profit from your test!
 

SnappingTurtle

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May 4, 2008
Messages
1,251
Re: Maxxon Boat will not plane!

This I would think would be the obvious solution and I always hear good things from boaters that have them on small motors I meet in the water. But it doesn't seem to be the favored product of choice for boaters in the Internet, so I resisted the urge to suggest a fin. :D

Here is another link, this one is from iboats!

http://www.iboats.com/Doel_Fin_Hydr...12497944--**********.628375840--view_id.37915
 
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MikDee

Banned
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Jun 6, 2007
Messages
4,745
Re: Maxxon Boat will not plane!

Hey, Iboats is even Cheaper! But, true, I should have looked there first, and if I was about to buy one, I'd take my business right here!

I know, I'm going against the naysayers here suggesting a Hydrofoil, but sometimes they do the trick!
 

SnappingTurtle

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May 4, 2008
Messages
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Re: Maxxon Boat will not plane!

For many reasons I am going for a Hydrofoil, even if it is not the product of choice. :D
 

shanonamous

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Jun 1, 2008
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Re: Maxxon Boat will not plane!

That Davis Instrument's Doel Fin you both pictured is the one that I got. I can't wait to see if it is the magic fix I am hoping for. I have had a couple different hydrofoils in the past on different boat/motor combinations with mixed results. The best was on an 11' inflatable with an 8 hp and a fin and it planed out well with two guys and handled great. Another was on an 18' Klamath with a 40 hp equipped with a Stingray hydrofoil. That setup was downright dangerous. It did alright in saltwater because the slow planing speed was good in the chop, but running in the rivers would plant the bow into the current and the boat would dart erratically. Anyways, I will be playing with it this weekend and fishing all next week. Your right about the dealers. At least the ones here are relatively clueless, but that doesn't stop them from trying to sell you something. I will report my results soon, wish me luck.
 

Shawn_floats

Seaman Apprentice
Joined
Feb 3, 2008
Messages
35
Re: Maxxon Boat will not plane!

Whoa - 15HP and won't plane??

There is something seriously wrong.
For years I had a 10 1/2 foot Zodiac that had a 9.9HP on it - and with just me in it, it would practically throw you out of the water onto plane. It took about 2 seconds.

3 Adults, it would plane fine also, but had to balance the boat a bit (ie put someone up front).

I never had any "extra" stuff added to it. Just Zodiac and a stock Yamaha motor.

With an 11 foot inflatable and 15HP motor, I can't help but think that something is very seriously amiss. It should be like riding a 15HP floating motor.

Can you take a photo of the shaft to transom angle?
 

shanonamous

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Jun 1, 2008
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Re: Maxxon Boat will not plane!

I tried out the Doel fin last weekend and was rather impressed. The boat speed is about the same at around 12 - 13 mph GPS, but the handling was immensly improved over the lifters. There is also no noticeable porpoising now and the ventilation problem on the propeller was great decreased. The Doel Fin was a third the cost of the lifters and works better on this particular boat than the lifters. I am looking into getting a new prop with a lower pitch now. I am running a standard 9.5 X 10 three blade and I want to try a Solas Amita 9.25 X 8 four blade prop. The boat itself is light, but is usually loaded fairly heavy. I am hoping the four blade prop will completely eliminate the ventilation and I also hoping to get a couple more miles per hour top speed with the lower pitch prop. I currently don't think this motor is revving up high enough to meet it's full potential, but it's hard to tell with no tach.
 

MikDee

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Re: Maxxon Boat will not plane!

Glad to hear it worked out for you, I thought it would. ;) There's one more thing to check, make sure your cavitation plate is paralell (flat) with the bottom of the boat (the motor angle) this is the normal (standard setting to begin with!). Just find the right hole to put the rod in, because if the motor is angled too low, or too high, it may cause ventilation either way. The next thing to check is if your motor is too high, or too low on the transom, the cavitation plate should be flush, or a bit higher then the bottom (this is another normal, or standard setting) but sometimes harder to correct, it means shimming the motor up, or dropping it down. Ok, hope this helps also, good luck, Mike
 
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