What happens if I am cruising along and hit something hard with my outdrive?

[scooper77515]

It is a VolvoPenta SX outdrive on 18.5' boat.

My dad says his old outboards would just lift the engine (swing it back and up) if he hit something hard or hit the ground.

Will the outdrive on mine do the same, or will it do something else?

I try to run with the trim up a little, like 15-25% up while I am cruising, but what about if it it was all the way down and I hit a large log. Would it pop up a little, or just break off, or tear the rear half off the boat?

May sound like a stupid question to some, but I am new to this kind of boat setup.

 

[DBreskin]

Re: What happens if I am cruising along and hit something hard with my outdrive?

If you hit something with your outdrive it will NOT pop up.

The amount of damage depends on how fast you're going, how big an object you hit, and how much you hit it. With enough speed and a solid hit you can break off your drive.

 

[scoutabout]

Re: What happens if I am cruising along and hit something hard with my outdrive?

I remember reading something about Mercruiser outdrives which said the rams are pressurised on both sides, which holds the outdrive at a specific angle. If you were then to strike something hard, a valve on one side of the ram is actuated which allows it to pop up, aided by the pressure on the other side.

There are experts here with far more knowledge that I which can chime in with exact details, but I'm sure Volvo has done something similar.

 

[Joshua Nichols]

Re: What happens if I am cruising along and hit something hard with my outdrive?

You grit your teeth and think damnit.. Be careful on that lake.. There is ruthless stuff out there.. I hit something while I was out there(over by the RV park by the gas pump) and it wasn't nice.. There is stuff sticking out of the water everywhere.. Stick to that deep cove..

 

[rwidman]

Re: What happens if I am cruising along and hit something hard with my outdrive?

It is a VolvoPenta SX outdrive on 18.5' boat.

My dad says his old outboards would just lift the engine (swing it back and up) if he hit something hard or hit the ground.

Will the outdrive on mine do the same, or will it do something else?

I try to run with the trim up a little, like 15-25% up while I am cruising, but what about if it it was all the way down and I hit a large log. Would it pop up a little, or just break off, or tear the rear half off the boat?

May sound like a stupid question to some, but I am new to this kind of boat setup.

If you trim your outdrive up 15-25% while cruising, it's not very efficient and you would be raising the bow of the boat. You also lose a lot of steering control.

You should adjust your outdrive trim to trim the boat for best efficiency. That's what the trim adjustment is for, not for avoiding hitting things.

This forum has a section for specific engines and outdrives. I suggest posting your question (complete with year, make and model of the outdrive) in the appropriate section for a more "expert" opinion.

 

[DuckHunterJon]

Re: What happens if I am cruising along and hit something hard with my outdrive?

It won't pop up like a small outboard would. The trim cylinders are attached to control motion in both up and down directions. Some outdrives had pressure relief valves inline with the retract line of the piston, such that if you hit something hard, the valve would open and allow the piston to extend. Even with this, it would be slower to react than a small outboard.

As for how much damage, I'd say it's a function of how fast you are going, and how immovable the object is. Yes, I saw an entire transom ripped off once. It was on a shoal in front of my grandparents cottage, and the boat was doing about 50 (guessing) when he hit it. That same shoal was hit a few times a summer, and most of the time the boaters were able to limp to shore with a busted up prop. This particular one just hit it at the wrong time of year, from the wrong angle, and at too fast of a speed.

Hope that helps.

 

[ziggy]

Re: What happens if I am cruising along and hit something hard with my outdrive?

my experience is only hitting uso's at low speed.

i've hit sand bottom at idle. that just shined up my prop

i hit submerged trees or stumps this year. was at idle. put a couple of small dings in the perimeter of my aluminum prop.

i hit something at speed on the river once. that broke off a half of a whale tale + broke my anti vent. plate. don't know what i hit..

i can remember dad hitting rocks at idle or just above. that broke chucks off the aluminum prop.

years ago, my neighbor won a law suite and got a million dollars. he bought a large boat. go fast type. he came back one day from the river with his drive hanging by cables. said he hit something hard. i believed him even if it was an idiot.

don't know about your drive. i agree with

I remember reading something about Mercruiser outdrives which said the rams are pressurised on both sides, which holds the outdrive at a specific angle. If you were then to strike something hard, a valve on one side of the ram is actuated which allows it to pop up, aided by the pressure on the other side.

i think i've read that too but have no further knowledge about it..

my word of wisdom is to stay where ya know (or at least think ya know) there are no uso's. i don't have sonar so stay well into the deep. if i do go shallow. it's at idle. if i feel like there may be uso's anywhere around, i go to idle. i may still get one someday. but it'll be something that's unmarked and not normally there. ie. the wood end of a large cable spool that was floating down river one day. i floated over that one w/o indecent. darn sure hit it though. heard and felt it go underneath me. if i'd have hit it at speed, i'm sure damage would have occurred.

 

[diesel5599]

Re: What happens if I am cruising along and hit something hard with my outdrive?

I saw a guy with a Mercruiser outdrive forget to raise his drive when leaving the ramp and dragged the boat up the ramp, by the time he got to the top he no longer had an outdrive. If it did not adjust to that kind of long slow extreme pressure, I highly doubt your drive will react to hitting something underwater.


I've hit plenty of sandbars in the past, the worst that happened once was some ring inside the prop shaft sheared off and I had to be towed home, cost about $30 to fix, but a sand bar is a lot different from a rock bottom or a log.

I have also heard of people hitting something so hard that the prop gets bent and the resulting vibration causing the engine to throw a rod before you get a chance to shut it off.

 

[rwidman]

Re: What happens if I am cruising along and hit something hard with my outdrive?

I saw a guy with a Mercruiser outdrive forget to raise his drive when leaving the ramp and dragged the boat up the ramp, by the time he got to the top he no longer had an outdrive. ............

And that is one of the reasons a person who thinks about what he (or she) is doing will open the windows and turn off the radio while doing something like this or even for the first 1/4 mile or so of trailering - to be able to use one more sense to find a problem. With the windows down and radio off, most people would have heard the outdrive dragging and stopped to see what was causing the strange sound.

You can't fix stupid!

 

[shrew]

Re: What happens if I am cruising along and hit something hard with my outdrive?

I've seen props completely destroyed and skegs torn completely off of both Volvo's and Merc outdrives. On an outboard, the entire motor, shaft and lower unit can all pivot. In a outdrive it's not the same. In addition both volvo and merc. don't recommend running above somewhere between 800 -1000 rpm with the outdrive out beyond trim limit, which should be a bit less than 1/2 way out because it can damage the drive itself.

It would be nonsensical to make a safety feature to allow the drive to pop up which inadvertantly damages the drive as a result.

Solution: pay attention to charts, depths, depth finder. Navigate unknown waters with extreme caution. Give aides to navigation adequate clearance.

 

[scooper77515]

Re: What happens if I am cruising along and hit something hard with my outdrive?

I run all the.way down then up just 15-25%. So most of way down all the time. Boat likes to ride there.

 

[Brewman61]

Re: What happens if I am cruising along and hit something hard with my outdrive?

It is a VolvoPenta SX outdrive on 18.5' boat.

My dad says his old outboards would just lift the engine (swing it back and up) if he hit something hard or hit the ground.

Will the outdrive on mine do the same, or will it do something else?


May sound like a stupid question to some, but I am new to this kind of boat setup.

What happens? Anything between utter destruction of the drive, to absolutely no damage at all, depending on countless variables- speed, object struck, etc..........

Can it be damaged? Sure. But so could your dad's outboard.

Not sure about Volvo, but my Alpha II has the ability to swing up when impacting an object, which coould potentially minimize potential drive damage, but again, that depends on the variables...............

 

[nlain]

Re: What happens if I am cruising along and hit something hard with my outdrive?

On my 04 Alpha 1 Gen II it will kick up and return to running position, I had read that in the manual and have experienced that twice. I do not know how the Volvo's are set up. My old Alpha 1 would kick up and stay, had to use the trim button to bring it back down. I would think they would have the same ability today.

 

[scooper77515]

Re: What happens if I am cruising along and hit something hard with my outdrive?

So can I test it by just trimming the engine down about half way (on trailer, engine off) and pulling up on it by hand? Or will it take more force than that, or would engine need to be running for those functions to work?

 

[nlain]

Re: What happens if I am cruising along and hit something hard with my outdrive?

It will take more force than that.

 

[bruceb58]

Re: What happens if I am cruising along and hit something hard with my outdrive?

So can I test it by just trimming the engine down about half way (on trailer, engine off) and pulling up on it by hand? Or will it take more force than that, or would engine need to be running for those functions to work?

Waht do you think happens when you put your engine in reverse? It puts a whole lot more pressure than what you can pull.

 

[Leisure]

Re: What happens if I am cruising along and hit something hard with my outdrive?

Your best source of information on this topic should be your operators manual. Here's what my OM says ('07 Volvo 5.7 GXi w/SX-A drive):

"The trim/tilt system provides impact protection in the trim/tilt cylinders. If an impact occurs while in FORWARD motion, the cylinders will allow the drive to 'kick up', thereby helping to minimize drive damage."

And here's another equally important tidbit:

"When backing-up in REVERSE, there is no impact protection. Be very careful when backing-up in REVERSE. Do not exceed 2500 RPM."

 

[bruceb58]

Re: What happens if I am cruising along and hit something hard with my outdrive?

And here's another equally important tidbit:

"When backing-up in REVERSE, there is no impact protection. Be very careful when backing-up in REVERSE. Do not exceed 2500 RPM."

That's probably because in reverse, when you hit something, the drive has no where to pivot, plus you have a prop that is going to hit first.

 

[jkust]

Re: What happens if I am cruising along and hit something hard with my outdrive?

On my 04 Alpha 1 Gen II it will kick up and return to running position, I had read that in the manual and have experienced that twice. I do not know how the Volvo's are set up. My old Alpha 1 would kick up and stay, had to use the trim button to bring it back down. I would think they would have the same ability today.

Yep times two on the Mercruiser. Haven't had it happen yet but manual mentions it. I can't imagine the Volvo doesn't do the same. I have seen some pretty severely damaged new Alphaswhere it didn't matter though.

 

[642mx]

Re: What happens if I am cruising along and hit something hard with my outdrive?

This is what happens when you hit something at speed... http://www.youtube.com/watch?v=ucVAKNohgus Watch the left side of the screen real close at the 50 second mark. This guy hit a Ford van that was under the water.