hellomynameisdookie

Ok, recently I picked up an electric RC boat. My problem is only when the boat is in the water, not on land. It's crazy and I can't figure out the exact cause of it and it's driving me insane.

Here's the deal: On land everything (steering servo and engine) work perfect, even at a fair distance with a radio check. Once I place the boat in the water everything f's all the crap up. When I thottle up the motor it sputters....keeps cutting on and off, and when it gets about 25 feet out it'll throttle hard and the boat will go to the left without me turning it that way. It will only run correctly for maybe 2-3 seconds at a time, and this doesn't happen often. I've ran it in 3 different waters to make sure there wasn't interference at a particular place, but at all places it's the same thing.

I've changed everything on the boat except the steering servo- ESC, TX, RX, motor and still the same thing. It's works PERFECT on land, but once I set it in the water it messes up. Anyone have ANY ideas at all?

pompebled

Thats odd.

It seemes to me, that the recever signal is shortened when the boat gets in he water.
Try another transmitter/receiver set, if the problems remain, there's something wrong with the setup.

Regards, Jan.

LtDoc

'dookie',
My first thought is that the receiver or associated wiring (servos, etc) is getting wet, but I'd think you've already checked for that. Next thought is how/where is the antenna? If it's in the hull, the water may be attenuating the signal enough to cause a loss of control. I'd also think that the antenna would have to be well 'down' in the hull for that to happen?
Loss of control is usually associated with loss of signal, or the receiver is 'confused' by more than one signal (or in some cases just too much signal!).
It seems like the receiver is 'defaulting' to a 'full throttle' and 'full left turn' state, so try disconnecting the receiver's antenna, collapse the transmitter's antenna, and see if this 'default' state is also true for when it's 'on land' (is it really the 'default' state?). You may have to back off some distance to make the signal at the receiver 'small' enough. If it happens on land, then I'd think it's happening because of a loss of signal so getting 'more' antenna 'up out of the boat' should help or 'cure' it. (I'm reaching for 'straws' here, so take it for what it's worth.)
Some times you 'can't see the forest for the trees', so why not have someone else check things out? (I've ~<never>~ missed something obvious like that! Wanna buy a bridge?LOL)...
- 'Doc

hellomynameisdookie

Thanks for the quick reply!
Nope, nothing is getting wet. All of the radio gear is in a sealed radio box.

The antenna exits the radio box through a hole the size of the antenna wire, up through the hull via a rubber grommet that gets sealed when the antenna straw gets pushed into it. So the antenna actually sticks about a foot above the boat.

The only thing I haven't replaced is the steering servo, but that can't possibly be the cause of this, can it?

LtDoc

'dookie',
I wouldn't think that the steering servo would be the problem, but. If you happen to have another servo to substitute, why not, it couldn't hurt to give it a shot.
Is this a commercially made boat, or did someone build it from a kit? Some commcercially made boats have extremely short range...
- 'Doc

TERBObob

My Feedback: (21)

Try the simpliest first and then go from there .
First , I would switch out the servos , one at a time ( of course , I would use the rudder servo and not the throttle servo when testing in the water . )
Next , I would try the reciever ( which , IMO , sounds like the culprit )
Then , if these all check out good , then its time to hit the boat and make sure that the drive motor has a cap on both ends of the POS/NEG connections . ( might even try replacing them - they're cheap enough and found easily at a local RS store )

hellomynameisdookie

This is a commercially made boat. It's the Aquacraft Hammer (electric, RTR). I have replaced the motor with a Monster Maxx wild motor, the stock esc with a Traxxas esc (the one from the Blast), and replaced ALL of the radio gear (tx, rx, and now the steering servo), and dangit it still does it!

What is a cap?

The only thing left of the boat is the driveshaft! By any crazy chance, when I put the boat in the water could the water be pushing up on the prop and driveshaft and causing some kind of interference? If so, how do I fix this? I'm lost on this one.

TERBObob

My Feedback: (21)

Ok , a cap is short or a capacitor , which in short , eliminates RF caused by electric motors . ( along with many other uses as well , but for this application , it is used for elimination of interference from the motor )
Could it be the prop shaft ? Possibly , but , I would not think so , since ( I am assuming here ) that it is the same shaft as what was previously in the boat .
You could also try greasing that shaft up so that the grease is oozing out both ends ( man , good thing everyone knows what we are talking about here ... LOL )
But , anyway ... on that new motor , is there a cap on both ends ( positive and negative ) and the other end goes directly to the case of the motor which grounds the capacitor ?
You will definately need one on BOTH sides - the negative and the positive , of the motor connections . AND they HAVE to be RIGHT on the motor's connections directly .
If you need me to , I can scan a pic of what I am talking about and post it here .

LtDoc

Another question that comes to mind is, is the ESC capable of handling the 'hotter' motor? Exceding the capabilities of the ESC can cause a number of 'odd' things to happen.
- 'Doc

mayor greez

[8D]Hey Dookie, By any chance, do you have the RX inside a balloon? Reason I ask is that I've recently had the same problems and what I believe is happening is that since the receiver antenna, rudder servo and ESC wires all exit the neck of the balloon bunched up together, they are somehow interfering with each other. Believe me, I've tried every configuration I can think of in the last two days and the only thing that's worked for me is to take the RX out of the balloon and make sure that none of the wires are crossing or touching. Hope this helps...

bobjay

[&o]
Hi Dookie
Well ya state the boat works "OK" on land, but messes up in the warter. I don't know this boat, size wise. Maybe you have to find the common denominator! Is it WATER???? Working at home is the easy way to go. Put the boat in a tub of water and see if it acts the same as in a pond/lake. Then you can make changes moobetta at home , if water is the problem. As in other replies , check drive shaft, change/add caps, check by substitution (if ya can) as many electrical/electronic parts as possible. Test run LONG time, could be strange intermittant. If I think of anything else I'll post again. I'm inner rested in dis problem....
See ya
bobjay

hellomynameisdookie

The stock esc would have not handled the new motor, so I upgraded the esc to one from the Traxxas Blast (I know, not the best out there but it's cheap and can handle the new motor.) So I know it's no the esc, which was what I thought it had to have been.

The reciever did come in a balloon. I also thought that maybe since the wires were all twisted together that there was some interference that way, so the balloon went andthe interference was still there!!!

I also just changed out the steerign servo, so that wasn't it either because the **** still does it.

The last thing I've done, was install capacitors on the motor. Someone else suggested that idea to me as well, so I went with that. The Monster Maxx motor does not come with capacitors installed, inside or out. So 3 days ago I soldered them on and unfortunately I've been pretty sick and out of work and have not had time to test out the boat. I'm hoping you're right and it was because of no capacitors. I soldered one from the neg side to the can, one from the pos side to the can, and one from the pos side to the neg side, so If that's not he culprit I GIVE UP!!!

Thanks for the great suggestions, I'll keep you posted on the results.

mayor greez

[8D]I finally got mine working!! I'm a little embarrassed about it though...

The antenna tube comes pre-installed in the boat and is bent waaayyy down when the lid is on the box. The problem here is that this causes the antenna to run parallel (sp?) to the water which I've heard can cause interference although I had never witnessed it, not to mention that the antenna only sticks up about an inch or two above the boat. I simply replaced the bent over antenna tube with a perfectly erect one and it works beautifully. I'm sure there's a dozen or so "dirty" quips we can come up with to describe the problem, but I'll leave that all up to you guys...

-Mayor Greez

RussF

My Feedback: (4)

The drive shaft is the problem most likely. I also have a Hammer EP and experienced the same problems on about my 5th battery or so. The prop shaft is steel and the tube it goes through is brass. The tube has a sleeve at each end that the shaft rides on. The grease in that area cant last long and doesnt. Just pull out the prop shaft and re-grease both ends and that should help alot. It did for me. Keep it greased often and you should minimize the glitching problem.

skibum315

Dookie-

Another culprit that some have touched on but none have fully called out is that the antenna/signal wires should not run anywhere near the power wires under the deck. This (in short) is because one will generate interference with the other. Since the current in the power wires is generally much greater than the current in the antenna, the interference going into the receiver will be much larger - causing glitching.

Though this explanation should cause the boat to glitch both out of the water and on ... so it may not be the particular culprit you're looking for. I just mention it as good practice ... always keep signal wires as far from power wires as possible. I'd be willing to bet that the capacitors were your problem. Have you tested the boat since installing them? Hope it all gets sorted out.

Jonathan