Hydro Lock problem after towing R29S

[S. Todd]

We have a 2021 R29S le that has been used in Great Lakes fresh water. Boat has a Volvo Penta D-4 320. At 285 hours and 30 miles from our final destination on a 4-week cruise the engine belts shredded after what appears to be a failure of the idler tensioner for the belts. (Our bad luck because the 5-year warranty ran out less than 3 months earlier.) We rocked in primarily beam seas for about 3.5 hours before Tow Boat US arrived. The seas were about 1.5 foot at the start of the wait and shortly built to 3 footers. Lake Michigan waves are generally steep, so we rocked. While waiting for the tow boat I closed the sea cock to the engine. Tow Boat US did what I would describe as an excellent job towing us the 30 miles at about 7.5 mph. (I am thankful I have had Boat Us Towing insurance for the last 40 years and this one time I tried to use it there were no questions asked when I called for assistance.)
Boat is at mechanics and they discovered hydro lock and water in the turbo and all 4 cylinders from this event.
Has anyone else experienced this? Any good explanation of how or why this occurred. Is there a fix to prevent it from ever happening again in the event of a beam sea rock followed by a tow?

 

[scross]

Sorry for your engine damage.
Yes, many, many horror stories of this happening after a tow. The main cause is not closing the sea cocks AND not plugging the exhaust port prior to being towed. Plugging the exhaust port is crucial! Transmission put in neutral too. Even with these steps it’s possible for water to get into the engine through the shaft seal.
All tow employees should know to communicate securing the engine before a tow. It’s almost negligence that they don’t. But all inboard engine boat owners should know this too.

PS: Hopefully your insurance policy will cover the full engine repair/replacement costs. I called my agent and he believes my policy with Chubb would cover everything in this situation. Hope I never have to find out! The agent also thought your tow boat operator had a duty to go over securing your engine prior to the low.

 

[lproulx]

All may not be lost. Lake Michigan being fresh water means there are no corosion issues in engine. Starter motor trying to turn engine is not strong enough to do any harm (except maybe to starter). Have an engine shop get the water out and replace with new oil. I think they have techniques for doing this. You may be OK.

Larry

 

[PanaSeaAhToo]

Would you explain "plugging the exhaust port". I can't think of what I carry that would do this.

 

[PanaSeaAhToo]

Would you explain "plugging the exhaust port". I can't think of what I carry that would do this.

 

[scross]

We measured the exhaust port opening on our C-28 - it’s just over 3 1/8” according to my notes. You could plug this various ways. My plan was to use a hard plastic ball wrapped in a towel. The yellow plastic ball I have in my spares locker is about 2 7/8” in diameter. Never had to do this in real life but my plan was to wrap the towel around the ball enough times to make the fit into the exhaust port as tight as possible. Worked when I tried it with boat in driveway. The end of the towel sticking out would give me a way to extract the towel and ball.
It’s not a huge amount of back pressure you are trying to block. But unblocked enough to flood the engine. The higher the tow speed the greater the pressure. Slow towing speed is better.

 

[CaspersCruiser]

During on-water towing in Ranger Tug and Cutwater boats, water intrusion into the engine is a recurring problem apparently due to the way the engines are installed.

In 2019, while waiting for long tow in my 2012 R27 with the Yanmar 4BY2-180 engine, I called Mike Rizzo, a longtime R27 owner and guru, about how to prep for the upcoming tow. Besides making sure I had closed the seacock, he advised me to use a small pair of vice grips to pinch off the cooling water supply hose to the propeller shaft packing gland. I’m not completely sure of how that keeps water out of the engine, but no water got into the engine during a four-hour tow.

Todd, I know this doesn’t help your situation. I’m adding my comment here as forum corporate knowledge for folks making searches on this subject in the future.