On the rocks

[Pascal]

Re: On the rocks

Even if the rod side of cylinder was fully open, so the drive can swing back freely, I don't think it will save it from the impact, cosidering the mass and, therefore, inertia of the drive and speed of the boat.

It may not save the assembly from all damage nor am I saying it is designed to but it will limit the damage to a less than catastrophic amount. The owner/operator will still have to pay for their inattention.

It is a different story if the line bursts, from the normal operation when the fluid goes thru valves.

Different situation - yes. Same principles - yes. The fluid accelerates instantly to maximum velocity based on the force acting, the pressure developed and the size of the passage.

The principle involved with the tilt trim cylinders as shown with the boat in the picture is exactly the same as the principles involved in the operation of the shock absorbers on your car or truck.

 

[Aviator5]

Re: On the rocks

Thanks, Pascal! Was nice talking to you. According to your username, you are hydraulics expert? Where abouts in Canada are you?

 

[Pascal]

Re: On the rocks

Hope I've helped and it made sense. Ya, I've been in and around hydraulics most of my working life and it is one connection to the screen name.

From calgary area.

 

[Aviator5]

Re: On the rocks

Everything you said makes a perfect sence. My thought also was that those valves are not to protect the drive, but perhaps, transom from being ripped of at the impact.
Last fall when I pilled my outdrives for service in the end of season, I noticed a small dent on one lower gearcase, looks like hit by a bullet. Didn't leak but aluminum was cracked inside. Although I never noticed any impacts, or ubnormal drive elevation.

 

[Pascal]

Re: On the rocks

The transom is definitly protected but if your outdrive is struck by an object with less mass than itself the full impact will be absorbed by the surface struck. If the surface area is small enough it will create enough pressure to penetrate. Kinda like the difference between the result of using the same gentle force to push the end of a ball point pen against your arm as the nurse uses to give you your flu shot.

 

[wanttofly]

Re: On the rocks

What happened to the pics?

 

[Mark42]

Re: On the rocks

What happened to the pics?

Oh good. I thought it was just me.

 

[flycaster]

Re: On the rocks

Oh good. I thought it was just me.

I can see them.

 

[wanttofly]

Re: On the rocks

I see them again now.