Need help setting up a boat

[Brushlessboy16]

Hello All,

disclaimer- I am a boat noob- be gentle lol


The matter at hand- I just picked up a boat for free from a family member, its a miss bud hydro- ABS hull, dual mod 540 motors, and some top of the line 1200mah nicad batterys(for super speed[]) non sharpened aluminum turn fin, plastic stock prop, plastic non sharpened rudder.

After stripping down the boat yanking the old toasted batteries, the esc which was cudely made from switches and a servo.. I checked operation of the two motors. to my surprise they ran, not only ran but ran well... To get the boat runnable I tossed in a spare Modded mamba max from one of my cars, set it to run brushed mode and cutoff for 4s lipo. got all that installed, running 2x 2s 4100mah 28c SMC batteries. now off to the pond.

At the pond I found out that this thing does indeed float. yay! first instinct? yank the trigger, boat sounded like a banshee and started slowly across the lake motor were revving wayy high. was setting steering trim, then was goosing the throttle trying to get the prop to dig in.. after some different methods of applying power- the prop finally dug in and the boat got moving at a good click... But whenever I try and lean into the throttle the prop is spinning and the boat isn't accelerating- Cavitation I beleive?

How can i alleviate this?

Weight bias?
prop
lay off the trigger?

Another lesson learned- rc car drivers suck at driving boats...going slower doesnt make it turn any better...lol.

Thanks for bearing through my boat newbishness.
-Ben

Did some measurements- found out that the prop is somewhere between 33- 35mm (just from scaling from my picture)
if that helps..






Later in the day I killed the dual brushed motors and installed a system from one of my cars.

Aveox 36-15, and a setup the mamba max for brushless.

Went out and bought some 1/8in brass tubing and made a water pickup, motor cooling coil and a heat transfer tube setup to cool the Mamba max's heatsink

With the brushless system and water cooling I could barely get the boat to plane. had to literally had to pin the throttle with the prop cavitating and just wait for the boat to get to a speed where it would hook.

I think i might need a bigger prop?

Thanks for help in advanced.
-Ben

[domwilson]

I have the same boat. Try a Y534 prop. And make sure this thing is sealed around the seams as they do leak. Or you could hand launch by throwing it forward in the water.

[Flying Scotsman]

You are not a boat noob, all your questions are very valid. I trust that some others will chime with experience on that hull. Dom's suggestion to me makes sense. If you get bitten by the FE boating experience, there is no looking back.

Douggie

[bustitup]

sup BB from rcmonster

do yourself a favor and throw that boat in the trash before its too late

you think trucks are addictive?.....run out of these forums and heed my warnings

bustitup

[Efis]

Welcome to fe boats!!! Change the prop out and go have some fun.

Blake

[Brushlessboy16]

I have spent 5 bucks on the project so far... brass tubing and nitro fuel line- hull was free so I could care less.

if needbe I will yank my running gear and put it in a different hull.. Any suggestions for a mono or cat, maybe something that has hardware with it?

cars its a roller, is an boat without running gear a floater? lol


Will look into the prop- and thanks for the welcome. everyone :)

[Brushlessboy16]

I have the same boat. Try a Y534 prop. And make sure this thing is sealed around the seams as they do leak. Or you could hand launch by throwing it forward in the water.

tried that, rides on plane for about 20 feet then just falls on its face.

[domwilson]

I found that the red prop is just too small. I think it's an Octura X431. A large prop would make it go.
And make sure you grease up the drive train including the gears, straight shaft and thrust bearing.

[Brushlessboy16]

I have the same boat. Try a Y534 prop. And make sure this thing is sealed around the seams as they do leak. Or you could hand launch by throwing it forward in the water.

Have a link to this prop, i cant find it

[domwilson]

http://www.offshoreelectrics.com/pro...?prod=oct-y534

[sundog]

Looks are deceiving. I don't think that your esc cooling will be very effective. Water can't flow past the heat sink.

[Brushlessboy16]

It works fine. the 2 tubes off the main spar are purely for heat transfer.

and thanks for the link to the prop :)

[Jesse J]

I might reiterate sundog's concern - boat ESCs are usually very well cooled with plates full of water or lots of tubing to bring lots of cool water in contact with the FETs. Remember that the fins you have two tubes running through is in contact with the FETs only by means of a sticky heat transmitting adhesive. The other option is a computer fan.

[sundog]

It works fine. the 2 tubes off the main spar are purely for heat transfer.

and thanks for the link to the prop :)

They won't transfer much heat like that. If you haven't had problems, you're not running fast or long. Be sure to check it with your hand between runs before you try longer hauls.

There is a better fix: carefully remove the finned heat sink from the esc. Break out the 2nd and 6th fins and superglue tubing into the enlarged slots. Reinstall the heatsink 90 degrees clockwise (so the fins go parallel to the caps). Run gas line from one tube to the other tube on one end, and in/out on the other end. I've done this mod on a couple of airplane esc's with success.

[Brushlessboy16]

i know that its not the most effective way of cooling, its temporary- just somethin to take the edge off so to speak, worst case scenario- the esc still has overtemperature protection

couple questions.

What do you guys seal your stuffing tubes, hulls etc with.

Is there any way I can use the stock stuffing tube that exits the hull in the rear pad with a flex shaft? trim the stuffing tube down and get a strut.

Does anyone make a strut compatible with an 8th inch flex shaft?

The hull is ABS plastic, and I have my water pickup through the back of the hull- what can i do to brace/seal it to the hull?

thanks for the help :)