Any thoughts on how this happened?

[britscoot]

Genesis cat
150 cable well greased
leopard 2000kv
Grim 40x53 prop
4s lipos

Ran really well for 2 runs.

[britscoot]

Both parts still spin freely.

[m4a1usr]

Since that appears to have happened outside the hull, under water, and it occurred due to the flex binding, a bit more detail of your driveline is required.

John

[britscoot]

i dont really know what more i could explain.
Fairly new 150 cable with a 3/16 shaft well greased.
no Teflon liner.
Brass bush in the strut.
No damage to any other part of the boat.

let me know if you need more specifics.

Thanks!!

[carlcisneros]

possibly caused in part due to the drive dog not having enough free space between the strut and the drive dog itself. (need about 1-2mm for cable tightening.)
IF you look very close at the bottom portion of the cable, you will see the internal portion of the cable that is supposed to be inside the upper portion of the broken cable.
Again, this is a possibility.

Carl

[m4a1usr]

let me know if you need more specifics.

Thats fair enough. Did the water contain organics like branches, leaves, water lilies, etc? If something got wrapped around the prop the load could be huge. Were you running a large gap between the motor coupler and the stuffing tube? Makes a difference. No liner doesnt mean a thing. Did you have a large gap between the drive dog and the strut? I've seen this same thing happen before but usually between the coupler and the stuffing tube inside the hull where the flex shaft was unsupported.

John

[domwilson]

Was there anything between the two tubes? Like heatshrink?

[domwilson]

The reason I ask is there appears to be no grease at the point of damage.

[blackcat26]

Looks like there was too much unsupported length between the strut nose and the stuffing tube. Look at both ends, they are wallowed out. Prolly looked like a jump rope before it gave out...

[Alexgar]

ive had this happen with to much slack under load the pressure forced against the shaft caused tit to twist

[Alexgar]

i was posting as bj26 posted the same i agree

[keithbradley]

Looks like there was too much unsupported length between the strut nose and the stuffing tube. Look at both ends, they are wallowed out. Prolly looked like a jump rope before it gave out...

Cable whip,.... that would be my guess as well.

[Diegoboy]

Looks like there was too much unsupported length between the strut nose and the stuffing tube. Look at both ends, they are wallowed out. Prolly looked like a jump rope before it gave out...

[graill]

Looks like there was too much unsupported length between the strut nose and the stuffing tube. Look at both ends, they are wallowed out. Prolly looked like a jump rope before it gave out...

"prolly looked like a jump rope before it gave out"


I would go with that too. I did a piece a while back on flex shafts and them orbiting on themselves and their carrier at rpm. Its buried somewhere in here or RRR.

[domwilson]

That would explain the flairs on both tube ends.