Foxy

I'm really new at this, I don't even have a boat yet, but I do have a couple of ideas, although they may be outrageously poorly thought through, or unnecessary, because there is already a known method of doing what I'm thinking. Anyway, I thought I'd run them by you guys...

Runaways... What if the throttle sticks open due to a flat, or shorted by water, RX pack? My idea... a spring on the throttle servo, and removal of the idle screw. Does that sound feasible? I guess you guys don't run failsafes in these, as the last thing you WANT to do, is stop the engine on the water, unless you have to??

Rescue boat... I don't really want to have to carry an inflatable dinghy with me for rescuing the boat if it should stall on me, and this might sound really funny to some of you guys, but how about this...

A cheap crap electric boat with a guarded prop, and a 2m length of fishing line attached to the back (thats why I will make a guard for the prop), with a cork tied to the end of it. Pilot the 'rescue' boat out to the stranded gasser, and run circles round it, until you catch the rudder with the fishing line, then slowly 'tug' it back to shore. How does that sound? Ingenious, or ridiculous? If there is a known method of using a rescue boat, I'd be very interested to hear it. Anything that avoids me getting wet or having to paddle (which is what I do instead of swimming).

Lastly, I hear DSM (2.4Ghz spread spectrum) surface radios, aren't the hottest idea for gas boats, and I was wondering why. I have no problem using PCM FM, I have my FM module for my 3pk somewhere, but I use DSM highly successfully for my gas cars, and was wondering what changes in a boat?

Thanks guys.

sonicracing

Hi Jonathan, Lots of good questions there, I'll see how I go. Firstly, If you don't have a way of rescuing your boat - then don't run it. There have been several drownings of model boaters in the last few years trying to swim for there boats, not a good idea.

To use a spring heavy enough to overcome a dead or un-powered servo will flatten the receiver batteries very quick, not a good idea. Yes, ***** happens but there's no substitute for good preparation in the first place. There are several types of fail safe options available these days.

I have seen a few good ideas using a small electric boat to recover a dead boat but as my first paragraph says..... if you can't get it safely, don't run it.

Commonly used frequencies around the world like 27, 29,35, 36, 40,72 and 75 MHZ bands will "skip" on the surface of the water where as 2.4 GHZ is absorbed by water. This was explained to me by an electronics engineer with over 40 years experience (who also runs boats). Cars run on a solid surface and they are never too far away from the driver so they don't have a problem.

Notice what's in the background, not the girl, the inflatable I mean.

Hope this helps. Cheers, Danny.

Foxy

Thanks Danny, great info. I would never dream of swimming after a boat. I'm a VERY poor swimmer. I would always have the inflatable dinghy in the car in case it was needed, but I'd like to try the 'rescue boat' idea, cos it sounds like fun. I like to have a mission. I might even try to find a tug boat look-alike to try this with, especially since a tug has mid mounted prop(s), which would negate the need for a custom fabricated guard.

About runaways, OK, failsafe it is, I have all different kinds, including modded picos, so that won't be a problem.

Hm, interesting about DSM being absorbed by the water, I never would have guessed. As you probably know, in Europe, we primarily use 40mhz for FM, and I have a nice futaba PCM rx and module for the 3pk, so it's no problem. I will try the DSM first though and see how I go, I don't know what kind of distances I'll be running, I'll be running it in the Ionian sea, mostly very close to the shore and in shallow water, so I may be less affected, we'll see. Thanks for the info though, it's good to know why it doesn't work properly if I have any issues.

EDIT: Following your edit... Yep, I have one of those inflatables already.

Dan S

hey Foxy,

Only a hand full or people have had success with their 2.4 Spectrum in their boat.

The Futaba FASST system however is great and is working flawlessly in the boats and the range is plain crazy.

You can buy (or make) a Failsafe kill switch, if battery pack gets disconnected, becomes dead or switch fails the engine will be switched off.

Dan.

Foxy

Thanks Dan, that's good to know. My DSM module is Spektrum unfortunately, a decision I have regretted on MANY occasions, even with the cars. When I bought it FASST wasn't available, and I was too impatient to join the '2.4Ghz revolution' . My mistake.

I think I might be able to get the seller of the flying dragon I'm looking at, to throw in a FASST module for the 3pk and an RX, so that may be the way to go.

As for killswitches and failsafes, 20 years with cars (and 2 years lately with large scale gassers) means I have a few (including a modded pico killswitch for gas engines) lying around in the workshop, so don't worry. Thanks again.

mopartybob

bad thing about the crap electric boats is the crap range they have... [:@] ,I use one with upgraded electronics,attached to my fishing pole,(just in case it wanders outta range),usually,it takes one run,do a U-turn around the stranded boat,and bring'em both back in,takes less than 5 min. and your back on the water in no time, I've used a SpeKtrum module in my 3pj super for over 2yrs now in all my boats with NO issues,but with all the current info and the success of the Fasst system,i'll probably switch over also

mmurray70

I always run a failsafe AND a throttle return spring on all my models. It probably does kill the reciever pack much faster but I still get plenty of run time with a 1400mah pack. Theres a pic below of my throttle return spring. It works best if you can find a servo thats easy to turn without power on so you can use a light spring, some high speed servos are a little easier to turn. Im just using a standard servo in my boat though, and its working ok. I cant imagine anybody running a boat without a return spring, something that took so much work to build and would be so easily damaged in a runaway. I wouldnt take a chance on it.

Alot of people remove the idle screw and use the radio to set idle. This allows you to kill the engine with the radio which is a nice idea. But i really cant see how that setup can give a reliable idle. I think with this setup would you rescuing stalled boats far to often. I decided to keep my idle screw and have never had an engine stall yet. I've been thinking about putting a limit swith in my radio box so i can kill the engine when the brake is applied. Or maybe ill set the failsafe set point back enough to flip the switch. Just turn off the transmitter to kill the engine. Im keeping my idle screw either way!

Justaddwata

My Feedback: (3)

There are some failsafes out there that will kill the motor if power is lost - Probably the only true "failsafe" as it no longer has other causes for concern (like servo failure, linkage failure, battery/continuity failure, and so on). It uses a powered relay that when powered and normal will keep the kill switch open. With a loss of power or other issue the relay will close and instantly kill the motor.


Danny - wondering where you find one of those dinghy inflators Lucky man!!

As danny mentioned - there really is no substitute for a quality setup. Make sure everything is free but secure and eliminate any possible causes for issues. Additional Return springs really do not belong on a boat and may bring about new issues (while often not solving the problem in the first place).

mmurray70

I'm really surprised to hear so many boaters say this. I've seen this come up a few times and the anwsers are always the same. Throttle return springs are fairly common on RC cars. Why dont you guys see the benifit? Its such a simple concept and its the only thing that will help in the case of a loose connection (other the the relay you mentioned), why would you even take a chance on not using one? A bad connection really isnt that uncommon of a problem. The amount of current the spring drains from the battery is probably small compared to what the rudder drains anyway. Just get a good receiver pack and your all set. Open your eyes guys, just because boaters have traditionally not used throttle return springs doesnt mean its not a good idea.

Foxy

I have killswitch (open relay, pico, whatever) failsafes. You guys seem to be talking about them as though they're unusual, so I just thought I'd throw this out there. On the gas cars, we wouldn't run without a killswitch, or at the very least a low voltage failsafe. A car doesn't stop on its own like a boat, and has the potential to do huge property and personal damage. The car in the picture weighs 25lb and has thousands of dollars in it, I wouldn't dream of running it without an automatic killswitch.

This is a very good choice for little money, and will kill the engine in case of ANY kind of failure in the electrics, battery death, connection broken, tx failure, out of range, short circuited, anything, even if the servo wire gets cut somehow.
http://www.davesmotors.com/store/product2505.html

Dreamin Hemi

Nice idea...I currently use the Pico switch for my aerial photography plane...yes, I still fly airplanes .....been working great for years! I imagine that thing COULD do lots of damage, expecially to your wallet if things get out of control. My Savage 21 years ago ran full speed into a concrete school building and all I could do was watch. Lost the radio and she was screaming....very helpless feeling. So I suppose these failsafes just plug into the receiver?

Foxy

Yep, it needs a little bit of splicing, but nothing the average hobbyist cant handle. It plugs into any auxiliary channel.

Justaddwata

My Feedback: (3)

Basically the spring effort needed to overcome the movement of servo is reasonably significant - the stronger the spring needed - the stronger the servo and the more drag it will be dealing with. Plus some issues in the radio/servo will not allow the spring to return it anyway. Further to that the spring needs to move the carb all the way to the closed position - not an easy task for anything short of a high strength spring. After all that messing around - would you really feel more (or less) confident that your boat will stop if you have a problem?

If you feel safe with a spring - that is great. Not telling you it is wrong - just not what I would recommend as a solution. [link=http://photos.imageevent.com/justaddwata/lirace/huge/JAW%20Pic%20136.JPG]Some of my boats deal with multiple carbs[/link], linkages, etc. (More $$ and weight than Foxys car too. ). I want more reliability than a spring will offer.

EricOnTheWeb

Well I like the return spring idea... why not?... I'm sure with a little fiddling around, one could come up with a system that isn't to hard on the battery and servo.. I think that is a damn good idea. Power goes out, throttle shuts down, simple and keeps the 1,000 dollar plus boat from running away into the weeds or rocks.... POOF! look at hat fiberglass blow apart!![][]

Just the thought of that scares the crap out of me...


As for the tug boat idea.... I LOVE IT!! in fact, even before I get my RIO, I think I'll get a nice tug boat(electric).... that is an awesome idea!.. How about this one?

The Atlantic Harbor(AquaCraft) from Tower..

weathervane

I have a failsafe in my ShockWave 36. I also put in a kill switch in my Prather 46. Last year my carb stuck at 3/4 throttle in the Prather. It is a scarry feeling when you have no control over something.
My ShockWave I set the idle so I can kill the engine with the brake. The failsafe plugged inline with the throttle servo. If I turn off the radio the servo closes to a set point. My kill switch in the Prather is just a micro servo on the third channel. I hooked it to the ignition on the coil pack.

-Andrew

Justaddwata

My Feedback: (3)

Wonder if a return spring will save your bacon with a stuck butterfly

pedro2-5

i run two fail safes in my boats. the first is for loss of radio and the second is for loss of power to the servo .have had a tangle with the rocks at full throttle once ,verry messy

Foxy

No doubt!!! But you my friend have a sickness we can only aspire to. I was looking at your MSN group. Amazing that DeWalt Cat, really amazing.

weathervane

Probably not. The carb was locked up. I had to pull it off the boat to unlock it. I did not put it back on. I just replaced it with another one. I keep it and use it as a mock up piece.
-Andrew