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[andyn]

How about this then?

http://www.youtube.com/watch?v=U5tAq531Es0

[Harbottle]

There does seem to be an obsession with KPH/MPH among powerboat enthusiasts. While speed is important, I won a lot of trophies when didn't have the fastest boat in the race. Reliability does help. If sheer speed floats your boat try tethered hydros. It saves the cost of R/C equipment as well!

[LOCURA]

I have to admit it.

I have not yet run the Zenoah engine and the boat is on a shelf never having touched the water after a YEAR! Tried to sell it (cheap) but to no avail!!!!

Our club lost its water and I am thinking of running in a lake or in a harbour and I would prefer to go electric. Oh Dear!!

Back to the "Black Art" drawing board.

[nick_75au]

LOL, My 60 inch boat hasn't seen water for close a year either.

Nick

[scoop]

I have to admit it.

I have not yet run the Zenoah engine and the boat is on a shelf never having touched the water after a YEAR! Tried to sell it (cheap) but to no avail!!!!

Our club lost its water and I am thinking of running in a lake or in a harbour and I would prefer to go electric. Oh Dear!!

Back to the "Black Art" drawing board.

Try contacting the Townsville club, N.A. I'm sure they run IC's and I think a few of them are looking at running Offshore style I.C.  powerboats 
Regards
Scoop

[rathikrishna]

Good after noon friends..i am willing to post one of my experience here...i also was in a struggle, to make a faster craft..so tried many motors and batteries, some even without any ESC.making an esc is not a matter today,as you can simply make an ESC with IC NE555,as PWM oscillator, and its output can fed to BUZ type, or IRFZ type mosfets, can handle ample of currents as you increases the number of mosfets in your circuits.almost one power mosfet can handle 30 amps almost, so a bridged 6 mosfets can do the job nicely.but any how you will lost your battery instantly...
                                       So i turned to an alternate..i purchased a small chainsaw, equipped with a small 35 CC petrol two stroke engine, forced air cooled,pull starter, and it totally weight only 245 grams,include all CDI and Ignition coil.and its size was only just larger than a cycle dynamo.it pumps out around 2.3 bhp, at 16000 rpm,and we won the gold medal last year, as our intern competition was held up...it was based on pure petrol, and a little 2T oil...tidy...exhaust was concealed within the ABS cover...it works even now, and theres no any trouble. speed radar, in our institute shows it simply cruises more than 76 kmph on salt water. at first the prop was the problem to me as the craft speeds up, the cavitation destroys the prop..so i contacted a naval engineering firm and they made a prop for me, a three bladed stainless steel one..so you can try with some engine like that, or can go for engines found in agriculture sprayers..its so cheap to run and extremely reliable..cool

[50mm]

i've just read a reply to this thread and it made me laugh at some people ignorance, it stated that ''Perhaps it is a cop-out but electrics seem to be tooooo technical'', simple fact is once you have your motor in got the right esc for the job plugged a lipo in you never have to do any work apart from check the prop, grease up the shaft and tighten a few nuts and bolts, any 8 year old can do that! (although mom and pop will have to pay)

Ic if vastly more complex.

first off there's the challenge of setting up the engine (tuning) which in its self is hard work at time's and anyone will tell you, you have to diagnose issues when they crop up, if the high speed mix to lean or to rich, low speed the same idle speeds, checking if the glow plugs are the right temp for the engine condition, constant cleaning on the intake valves (carb) and this is if you run a single Ic, and this is just 2 stroke!

i run twin 2 stroke and twin 4 strokes regularly (offshore) getting both motors tuned the same is even more complex!

other issues you have is when an Electric boat fails to respond 'generally' you can make it stop using a fail safe since a lot of the decent esc have fails safes built in, IC don't, you have to add a fail safe to control the throttle servo which if your little 6v pack fails nothing works engines max out and poff bye bye boatie , then there's the added fact of the linkages (attatched to the throttle arm) although you have to be a total donut not to check them but its been known for a linkage to break or the servo yanks it off and yet again bye bye boatie!

Need we go on about fuel? balancing the boat while the tanks emptying, fire risk?

To much can go wrong if you are misinformed, sloppy or ignorant that its 'easy'. i have been Ic boating for more years then i would like to count and even i managed to crash and burn my IC into the sea wall recently with no chance of retrieval! (i think it was a rudder failure but was to late to power down) ...$1500 gone bye bye!

sure i have made my point here that IC is vastly more complex then an electric boat, i could go on with other things that you have to watch for but i think i covered the basics.

[rathikrishna]

Hai 50mm..it was a great information.. it must be complex..but if one can fix an electric motor to his craft, he can simply fix a petrol engine to his craft, if that engine came from a reputed company, as i used, indented for a chain saw..my craft clocked around 2500 kms, as my diary readings, but actual may be more..even then i haven't removed any part, inc carburettor, or exhaust silencer. the only thing i changed is the air filter element.it still pumps out lots of power and my main head ache is slipage of propeller from shaft, as i do not have any sophisticated lathe works around me...if one have a good quality stuff to workwith its not a matter about using an IC engine to ones own craft..but yes sure, we have to think many criteria , of safety compared to electrics..when compared to electrics ,IC engines will not compromise to a great extent...its designed for raw power without any remorse...so we must take care about it..i think so..its only my experience...as i lack any modern equipments and people to help here..so if i am wrong..apologize..

[50mm]

I don't dispute that swapping out a electric system for an IC is complicated its just a bit of common sense and using the right parts such as a decent engine mount with the rubber shock absorbers, you honestly why bother swapping out electrics for an ic system in one boat, it would be prudent to just have a new hull for your ic.

Apart from that its all relative to your knowledge if you know what your doing its straight forward (not easy) if you don't at least your in the right place to ask how!

As i said before i laughed at the ignorance of some who think ic is easy.

Thing is Rath........

that yes IC is pure untamed raw power but you forget that rpm is rpm regardless of its source, many electric motors can keep up with Ic if your prepared to spend the money that will buy you units that can keep up, but even then electrics can be very fast in the right hands, its just personal choice as to which system you wish to run.

if your having slippage of the prop to the shaft surely you would loose the prop, or its the wrong thread size? maybe try a larger shaft or re-cut the threads. if i misunderstood would you mean slippage of the shaft to the flywheel/coupling? if thats the case, i would suggest a solid coupling made of steel or aluminium tube, no need for a lathe if you can get some solid rods, as long as you have a drill with the right bits, and a tap and dia set you can cut the threads and secure with locktight.

[rathikrishna]

Hai 50 mm, you are true..all we know electric motors are much powerful than a IC engine in to a same size..i got some diagrams of a traction motor, one used in WDM railroad engines in my country..its a small 30 inch dia around, open wounded motor , is atually drives the entire train, while the diesel engine is driving only its generator.so no dispute...but a positive side i felt with IC engine is the running time..for a mere 300 ml of gasoline it runs more than an hour at speed...and yes i loss my prop if i push the throttle stick too far...because it as actually made out of a wheel spoke of a motor bike.when load reaches to a great level,the nipple starts to slips from its base..if it happend, it will be a lost for ever...so by coming months i have to go to a lathe and will clear it...thanks for the great advices...

[50mm]

if figured out your issues with the prop loss, with the rpm of the prop the shaft is spining faster then the prop, as the prop is under loa, litrally its undo its self of the shaft.

not sure what your using in the way of props and shafts but the way to not loose your prop is a simple washer and nut.

Take the washer and push on the end of the shaft, this reduce water intake up the shaft

take the nut and loosely thread it up to the washer

take the prop and wind it on shaft  thread as far as it will go with out being tight.

now hold the prop and take a small spanner or pliers and now tighten the nut ( so unscrewing it basically) to the prop as tight as you dare with out destroying your threads, now what should happen at full speed the prop is unable to move on the thread in fact its turning is aiding in keeping it on the thread, now you won't loose a prop, to get it off again just hold the prop and undo the nut, and now unscrew the prop, easy and it only took a washer and a nut!

[rathikrishna]

Thank you 50 mm...and i have ordered to a lathe work,to make a prop shaft for me with BSF threads, clockwise, as my gear box turns in anticlockwise..so i hope it works...thanks for the valuable advice...