posted 02-06-2012 01:37 PM ET (US)        

During a quick stop from plane, the operator pulled the throttle back quickly, intending to stop with the engine in the neutral position. The boat came off plane and the engine slowed down nicely, but, when the engine reached about 1,200-RPM, the computer put the engine into reverse and accelerated it up to the current throttle setting. Apparently the operator did not stop with the throttle set in neutral but missed neutral and left the throttle in reverse (at a fairly high speed). The engine went in reverse so fast that water was sucked up into the power head and the engine was ruined. No one on board was hurt but it was quit startling.

Insurance paid for the engine. There has been communication with Mercury and they are basically saying that they did not know the engine/fly-by-wire would do that.

With a mechanical throttle if you had missed neutral you would have known immediately and you would have pushed the throttle back into neutral. In this situation the operator had no idea the boat was not in neutral and was totally unprepared for the boat to go into reverse.

I personally have very limited experience with fly-by-wire controls, but I wonder if this would happen the same way on other brand engines such as an E-TEC with fly-by wire controls.

posted 02-06-2012 02:41 PM ET (US)            

I do not think that water can be "sucked up" into a power head by rapid reverse operation. Making way at a high speed astern and then shutting off the engine might allow water pressure to push water upwards into the exhaust passages, but, if the engine were running, the pressure of the exhaust gases should tend to prevent water from rising from the propeller hub upward to the engine. If this were not the case, then all outboard engines that were operated with the propulsion astern and at a good speed would be liable to experience the same outcome.

It sounds to me like the operator became confused, pushed the throttle and shift lever into reverse, then shut off the engine while the boat was making sternway at a good speed. This forced the water into the engine.

posted 02-06-2012 02:54 PM ET (US)            

I do not know if the engine was shut off or if it stalled but either way water intrusion ruined the engine.

posted 02-06-2012 03:22 PM ET (US)            

I've also seen Yamahas run in the same fashion.

posted 02-06-2012 03:47 PM ET (US)            

How fast was the boat moving forward when the motor was put into reverse and how long did it stay in reverse?

posted 02-06-2012 04:15 PM ET (US)            

just suffered embarrassment, no motor problems. And I'm not a beginner.

posted 02-06-2012 07:40 PM ET (US)            

Manual throttle controls on most marine gear applications won't allow this to happen until the engine slows down enough. And when it does, just like on a car, you know something is wrong, and hopefully you can react fast enough to nudge the throttle/shifter back into neutral

Now if the DTS has a reversal rate control, also known as a set point, then I could easily see how this could happen, reversal rate [or] set point being the RPM limit at which the lower unit is allowed to engage reverse. Missing the detent on the DTS is easy, and easier yet for a new boater, assuming it was a new boater. How many of you have taught a spouse or other how to drive the boat, or watched someone cowboy when docking a boat[?]

Stalling the engine and failure [due] to water ingress is very strange. I have come off plane in some boats and had the back swell roll over the top of the cowlings, intakes and all--a little spooky, but the baffles worked, and no water.

Loss of back pressure due to killing the engine while in reverse at a high rate of speed [is] possible, but unlikely. The engine would still spin down and create some pressure on the exhaust. Now, if the boat weight 5-tons, then maybe, as the momentum would be such that the back pressure could be overcome.

posted 02-06-2012 09:48 PM ET (US)            

http://en.wikipedia.org/wiki/Equipment_of_the_United_States_Coast_Guard

Did I miss something? Perhaps it is the boat mentioned here,

http://en.wikipedia.org/wiki/United_States_Coast_Guard#Boats

and here

http://uscg.mil/datasheet/spc-le.asp

the 33' Special Purpose Craft – Law Enforcement (SPC-LE). This was the go-fast boat that the Coasties were driving in San Diego when they ran over a family on a smaller recreational boat. Too much horsepower, too much youth, and an arch with blue lights can be a bad combination.

I think Homeland Security favors the triple-engine configuration, and perhaps so does the Immigration and Customs on-water assets, the ICE boats.

posted 02-07-2012 07:29 AM ET (US)            

They also covered "shifting into reverse at high speed" and apparently you can adjust the amount of friction you feel with the throttle.

The DTS takes little effort to move in and out of gear and unless you pay attention to what your hand it doing you can easily over shot neutral.

My father got behind the helm once while I was setting the anchor and almost threw me over when I asked him to "pop" it into reverse for a second. He was used to clunky cable controls and pulled back hard on the throttle.

Except for when trimming the engine, I generally don't hold the hand grip I hold the arm close to the base and control with thumb and forefinger. I feel it give me finer control on the throttle.

posted 02-07-2012 09:30 AM ET (US)            

Apparently the cylinder most affected is the lowest cylinder, which makes sense. Due to the in-line six arrangement, the bottom cylinder may be a bit lower than one would find on a V6 engine.

My explanation of this behavior is a follows: when the engine is cut back very rapidly the boat falls off plane immediately. This results in the stern of the boat going down and a large following wave from the wake overrunning the transom. If the engine has stalled at a point where both the intake and exhaust valve of the lowest cylinder happen to be open--such valve overlap is likely on a high performance engine--water could easily rise through the exhaust system and enter the lowest cylinder and perhaps even higher cylinders.

The weight of the VERADO would tend to make the transom sink more than might otherwise occur when coming off plane. If the transom sinks far enough and the wave from the wake is high enough, the wave passing by the VERADO may be high enough actually be higher than the lower cylinder(s). Also, as we know from nature as demonstrated in the Bay of Fundy, if a volume of water is traveling along a passage with some speed, the water can be propelled at higher speed as the width of the passage narrows. This situation may be occurring in the Verado. Even if the wave height is not high enough to reach the lowest cylinder, the push of the water into the exhaust passages may accelerate the water and propel it higher than the wave height.

See:

http://www.veradoclub.com/smf/index.php?topic=1423.0;wap2

What role has electronic control to play in this? Not much, that I can see. Cutting back very rapidly on the throttle appears to be the root cause. The weight of the VERADO probably aggravates the problem. The in-line six design may make the lowest cylinder even lower than in other designs.

The electronic fuel injection design also aggravates this problem. In carburetor engines the suction of the intake manifold may continue to pull fuel out of the carburetor when the throttle is cut. In electronic fuel injection, there will be no fuel provided when the throttle is pulled back. The difference is very noticeable. On my boat the motor has electronic fuel injection. When the throttle is cut back the engine speed immediately drops, and the boat speed reduces dramatically--much faster than it did with a carburetor engine, which tended to coast as it decelerated.

My take-away from this: don't cut back the throttle from full speed to nothing, especially if you have a heavy VERADO on a small boat.

posted 02-07-2012 09:32 AM ET (US)            

http://www.veradoclub.com/smf/index.php?topic=2972.0

posted 02-07-2012 09:46 AM ET (US)            

In the account of this accident it is mentioned that the engine had 20-hours of operation. I would assume that an operator would become accustomed to the feel of the throttle after 20-hours of operation, but, if executing some sort of emergency stop to avoid a collision, they might yank the control harder than normal. That is just human nature.

posted 02-07-2012 10:31 AM ET (US)            

When going fast forward and shifting rapidly into reverse, with traditional control cables, the engine usually dies and when in reverse gear with the boat still moving forward, the motor will turn backward due to the water flow pushing against the prop blades (now that the motor is locked into reverse gear). That can cause sucking up water into the exhaust valves. While the stalled motor is turning over in reverse rotation, the exhaust valves become "intake valves" and will draw in water.

Most often the motor will then hydro-lock and bend or break the connecting rods. On Yamahas this is usually confirmed by stored ECU codes for "incorrect cam timing" and "MAP pressure error". With the cams turning backwards the cam sensor detects a problem. Also with the reverse turning motor, the intake valve becomes the "exhaust" and pressurizes the intake manifold. The MAP sensor registers a pressure instead of a vacuum and also sets a code.

posted 02-08-2012 11:41 AM ET (US)            

It is possible that the gear case on the VERADO uses a different arrangement for the clutch than the typical outboard engine? Many years ago I wrote an informative article about the change in the Mercury FOURSTROKE outboards to a desmodromic clutch. See

http://continuouswave.com/ubb/Forum1/HTML/015209.html

posted 02-08-2012 01:02 PM ET (US)            

The propeller is directly coupled to the propeller shaft and therefore cannot turn (rotate about its axis) faster than the propeller shaft unless the coupling between the propeller and propeller shaft is broken.

posted 02-08-2012 02:31 PM ET (US)            

1) Obviously the engine did not stall coming off plane or it would NOT have gone into reverse.

2) Obviously he was not just under the neutral click he was pretty far back in reverse or the boat would not have slammed into reverse, almost killing people aboard, and moving so rapidly backwards that it ingested water. IF you were still moving forward and slammed a boat in reverse it will not throw people around if they are properly seated. It will be in reverse but still moving forward for a moment until the reverse thrust overcomes the forward momentum. This does NOT happen instantaneously or else the Titanic would have not hit the iceberg...capeesh!

3) If you are a new owner you SHOULD read the owner's manual as it is filled by roughly 60% of it's pages with WARNING signs and notes of what NOT to do.

4) Lastly even though I have no formal credentials to show the forum today, why on earth does this whole thing sound fishy? First it was NOT just a common mistake that this person was coming off plane and missed neutral, went into reverse and somehow stuffed an engine. Ok I might buy that as I would not put it past Mercury to design an engine that can be destroyed so easily. But I would not believe that they did not ever try doing that during the 10's of THOUSANDS of hours of testing(c'mon REALLY). Now we find out the engine was hard to port or starboard when it happened.

So mister 6992WHALER I just want to ask you a question about your "friend"(in my best Columbo voice). You slammed me about my first post but I was on the right track. This "person" is a newbie or does not have much experience. I believe he was in a panick situation where he was about to hit somebody or something and did as described on PURPOSE in order to avoid a collision. Reason I say this Mister 6992WHALER is that if a person was just nonchalantly coming off plane for whatever reason and missed neutral he would have immediately just clicked it back into neutral and we would not be having this discussion. The reason why he ruined his engine is because he saw he was going to hit something, yanked the steering to one side and slammed it into reverse full throttle. This had NOTHING to do with drive-by-wire. Your "friend" is lying to you or you are lying to us. If he would have done what you described the boat would have never gained so much reverse speed to ruin an engine....case closed!

posted 02-08-2012 02:48 PM ET (US)            

The sun got in his eyes so the sunglass manufacturer is to blame too. :-)

It's almost spring!

posted 02-08-2012 05:25 PM ET (US)            

This thread has been a very interesting and civil discussion I hope we can keep it that way.

I think I made it clear in the opening post that the operator made a mistake, He will be the first to tell you he missed neutral.

The two basic conversations in the thread are: The characteristics of DTS shift compared to a mechanical shift. And the second the damage done to the engine caused by the maneuver.

I sent an email asking for clarification of some of the questions asked on this thread.
Here is some more information obtained from the response to my email.

The driver of the boat is a very experienced on the water instructor.
There were two other instructor on the boat at the time.
The boat had 11 hours on it.
The three instructors were new to the boat and were on it to learn how it handles so they could use it to train their students.
The instructor driving has lots of experience with 2 stroke outboards and mechanical throttles. He missed the "very light detent on the shift control".

When the boat was put into the Quick Stop Maneuver the operator missed neutral the engine slowed down and then went into reverse and then stalled.
The engine would not restart. In the shop the engine had water in three cylinders.

Mercury denied the warranty claiming it was an abused engine, insurance covered it.
The feeling is that Mercury has not been able or maybe willing to explain how this engine was damaged.

posted 02-08-2012 10:07 PM ET (US)            

I don't doubt Mercury denied the claim as it was clearly driver error, experienced or not.

To ANSWER your question...a mechanically throttled engine would have either....

1) shifted right into reverse at speed or grinded a bit and the shifted.

2) Blew the lower unit to Bitsies.

3) Snapped a drive shaft or stripped the crank where the driveshaft mates.

Everything except #1 would have NOT resulted in a blown engine from water ingestion. Does that help the suit?

posted 02-08-2012 11:42 PM ET (US)            

As far as the helm being hard over, if you had training in high speed boat maneuvering and someone had told you they had done a quick stop or a high speed stop you would not be asking why is the helm hard over. Being good at handling a boat does not mean you actually know the best way to handle one.

posted 02-09-2012 03:35 PM ET (US)            

Then give all the information up front instead of me having to squeeze it out of you. You never mentioned he was in a panick situation...I did in a post a few back. I KNOW why the helm was hard over but you never said why until I pointed it out.

posted 02-09-2012 03:46 PM ET (US)            

1) in your initial post you never said the engine stalled. In your 2/8 5:25pm post you said "When the boat was put into the Quick Stop Maneuver the operator missed neutral the engine slowed down and then went into reverse and then stalled."

Hence my rebuttal at 10:07pm. Sorry that I did not see the e-mail part. Next time your "friend" is out doing stupid shit and the engine stalls after trying to submarine it, tell him to bring a sparkplug wrench and drain the cyls before trying to restart. Will keep his insurance company from dropping him.

posted 02-09-2012 04:24 PM ET (US)            

I have no interest in what you have to say, which is to bad because you appear to be an intelligent knowledgeable person.
If only you did not have to be so negative, and angry.

Please go start your own thread.

posted 02-10-2012 10:11 AM ET (US)            

The first time I experienced a 4 stroke engine I did not realize I had started it so I started it twice. When I put it in gear it was so quiet that I applied too much throttle. I did not realize how much I listened to the sound of the engine when I operate an outboard engine.

Now add a control system that is easier to move with an engine that is much quieter. In other words take two senses hearing and feel, and change what the operator is use to.
I can see how there will be many experienced operators who will feel very inexperienced when they use this technology for the first time.

posted 02-10-2012 11:48 AM ET (US)            

I can see this happening on any boat, not only with electronic controls. I tightened my throttle to keep it steady at running speeds but think that it helps to keep this type of thing from happening.

The engine should not have failed like that. A wave hitting an outboard is not a freak accident! This sort of thing probably happens every day. What if this boat was twenty miles off shore maneuvering near a rocky island?

Picture yourself getting close to a rocky point that is new to you. Suddenly, you see a rock line just under the surface twenty feet in front of you. What do you do?

posted 02-11-2012 11:25 AM ET (US)            

http://continuouswave.com/ubb/Forum6/HTML/001766.html

It is interesting to note my comment from that article regarding the control friction setting.

quote:

---

... talking about the friction setting on the DTS controls, which I thought was universally set too low. [The Mercury representative] explained that there were friction controls to adjust the levers, and more drag could be added if desired. This was also news to me, as no one had ever mentioned this before. Most of the DTS controls I have operated have been set to almost no drag, giving them a feather light touch, which I always thought was too light. More friction was needed. The adjustable handle friction is very welcome.

---