walking a Tom Cat

[thataway]

OK--no leashes..we are talking the boat here. Yesterday I had a chance to use a manuever I have been practicing. There was an ultralight airplane crash, and we were involved (under the direction of an "expert") with attempting to bring it back on its floats.

The scenerio was that the wind was blowing from the STB side, and we had to be straight ahead of the floats. We had an approx. 100 foot tow rope which the expert had attatached to the pontoons, and with the wind the boat would drift to port, ruinging our alignment. I had the crew holding the tow rope clear of the props. We were taking the load on the stern eyes, with a fairly short bridle, where the bridle went outside of the aft ladder railings, and under the cables to the motors.

I put the Port engine in FWD and the STB engine in REV. With turning the wheel, and applying judicious power, I was able to walk the boat sideways into the wind, until it was lined up exactly.

The motors are set up so that the Right hand engine is on the port side and left hand engine on the STB side--common in cats, but not in twin screw boats. The walking action of the port motor in FWD is to STB, as is the walking action of the STB motor in reverse--so that the stern is walked to STB. You apply enough power to each engine to avoid rotation of the boat, and keep the boat moving, and "steer" with the wheel to get to the position of alignment. Then both engines in FWD and take up slack. We could do this without putting any strain on the tow line, untl it was aligned.

Unfortunately we were not able to right the plane, and it is still sitting in the bay. Last I heard they were going to dis-assemble it in place, but no one has arrived to do that, and the police just came around--media will follow. The owner didn't go to the hospital immediatly as was suggested, but was taken by paramedics today. It was a direct fall from about 50 feet, the lap belt only.

I'll stay on the water, thank you!

 

[Sea Wolf]

Bob_

Interesting!

Photos on the 6 o'clock news? (Did you get any?)

Joe. :teeth :thup

 

[thataway]

It may be on the news tonight--but no one reported it yesterday (the ultra lights crash on a fairly regular basis, and usually no one is hurt and the get the planes back up). This time the plane went down in fairly shallow water, and the wings were on the bottom right after impact. As of noon today the CG or Marine(Fish and Wildlife commission) had not yet been notified, but once the Sheriff's dept was notified, they would be. Since these things happen regularly, and most of the time people walk away, (swim away)and the plane is towed home--there are no reports made.

The frightening thing is that the husband had to dive 3x to get his wife clear. Fortunately he got her out before she drowned. But it must have been close. We got to the crash sight about 6 minutes after crash, and the couple were just being helped into the other boat which was nearer.

The husband did fracture a vertebrae--moral--go to the hospital immediately when you have a crash--plane or boat!

 

[matt_unique]

... The walking action of the port motor in FWD is to STB, as is the walking action of the STB motor in reverse--so that the stern is walked to STB. You apply enough power to each engine to avoid rotation of the boat, and keep the boat moving, and "steer" with the wheel to get to the position of alignment....

Interesting...could be a handy maneuver if you essentially need to crab into the wind. What kind of power settings/steering did you employ? You would have to turn to port to avoid rotation and I assume use more power on the port (forward) engine to keep the lines taut.

 

[thataway]

Actually we didn't want any pressure on the lines--since it would tend to pull the plane the wrong way. Since I was not aft, I could not sense how much pressure, but the crew held the lines with one hand.

Yes, there is more throttle than you might expect--this is an agressive power manuever, not an idle turn around maneuver. The reverse needs a fair amount of thrust, since the prop is more effecient in foreward, an d you have to ballance the fore and aft thrust of the two engines, and as you creep around keep the same amount of slack/tension on the tow lines.
The boat will be crabbing, and the steering is what makes it walk without turning the boat around. I was not watching the tack all of the time, but one hand was constantly on both throttles, and the other on the wheel. (spinner knob). The tendancy of this maneuver with no "rudder" is to turn the boat to the right, so you actually have to steer slighly to the left. (as I described the maneuver--the opposite if walking to Port). There was also a bit of back and forth movement of the wheel, and both throttles to get the correct balance, as the boat came around. Then when lined up, the port engine dropped back to an idle, and the stb out of reverse to an idle, steering straight ahead and slowly take up the tension to start the pull. This is something very similar to what the Zeus props or the Volvo pods do with their directional steering, but there the units move independantly and are comtrolled by computers. I am not sure you could do this as effectively with inboards, although generally "walking" is a bit easier with inboards.

 

[hardee]

Interesting maneuver. Thanks for sharing it. Do you think it would work with my 22 Cruiser and twin 40's (that are not counter rotation propped)? I can't say that I have noted "prop walk" as a usually response in docking or running.

I routinely use the throttle and forward-reverse systems for turning in tight places. Have learned to both spin and shuffle, - (my term for spinning and moving forward or reverse as needed), with no hands on the wheel and OB's parked dead ahead.

Harvey
SleepyC

 

[thataway]

Harvey, it may work one way, but not the other, because of lack of counter rotation. But--since there is torque/prop walk in one direction in reverse (greater than in FWD)--and I don't think you will get any help in the walking form the same rotation in fwd.

Incidently I am looking for a smaller cat to replace my "bay" boat--and so far all of the Honda 90's I have seen were RT hand rotation. Not sure if they didn't come in counter rotation, or if they were just more expensive.

I am looking for a single engine cat, BUT, all of the ones I have sea trialed have ventiallation (cavitation) problems. Not a problem with the twin engine cats. It makes me appreciate the Tom Cat even more! A couple of boats I have looked at were so bad, I didn't even consider running them....Oh--my "big boat" budget just bought the lot next door for Marie!