I need help understanding

[dwna1a]

i need help understanding something, I has nothing to do with my boat. I'm just curious.

So after last nights very bad storms I went out and towed a single engine 24' I/O in. He was running about 4000rpm in rough, wind blow waters. He says he was trying to beat the storm. He heard a loud noise then lost the drive. Engine was running great just no go.

My questions are, How much stress can the internal parts take? Can bad water conditions and hard running really blow one of these up? What is in there to just snap?

 

[Gofirstclass]

I certainly am not a mechanic and didn't stay in a Holiday Inn Express last night but I'd venture a guess that it could be that somewhere in the connection between the engine and lower unit was what blew and that was caused by the pounding of the boat. That pounding could cause a widely varying drag on the props (high drag when the boat is fully in the water, lower drag when the boat is partially airborne). Those instantaneous changes in the amount of drag could have caused the whateveritis to have blown.

See, I told you I ain't no stinkin' mechanic.

 

[hottoddie]

I suspect a failed drive coupler or possibly a spun propeller hub.

 

[scoflaw]

Agree with GFC, probably has an Alpha which isn't very robust to begin with.

 

[sbw1]

I always worried a little bit when running an I/O boat in a big following seas where the boat would be running at cruise speed, come off the top of a large wave, and then then crawl up the back of a rogue wave. The RPMs would go from normal cruise to maybe 500 or more lower at the same power setting before regaining normal cruise. I've done this for hours at a time with no issues, but never felt completely comfortable doing so. I guess the design is solid.

 

[dwna1a]

Well I've offered my truck and I to help get the boat up onto its trailer later today. I guess we will see something that might point up in a direction.

 

[dwna1a]

Hauled her out yesterday. It appears to have broken the prop shaft. No damage to the prop at all. A small portion of the skegg is gone.

 

[Gofirstclass]

If that shaft is all that's broken and you're missing part of the skeg, you may be able to collect the repair costs from your insurance.

However, if the cost is relatively minor it probably wouldn't be worth reporting.