Reply
 
Thread Tools Display Modes
 
Old 08-19-2015, 06:42 PM   #21
Guru
 
Sailor of Fortune's Avatar
 
City: Saint Augustine, Fl.
Country: Port of St Augustine ,FL
Join Date: Sep 2009
Posts: 1,969
"Real world you're probably going to approach the dock at minimal speed, with a bow "in" angle and then reverse the outside engine, maybe a little forward thrust with the other, to move the stern to the dock as you come to a stop."
This is incorrect.
If you want to walk to a port side moor, come in at an( bow towards) angle (slowly) and turn your helm to STBD (away) from dock while backing the port engine and ahead on the stbd (outboard engine). The momentum of the turn away from the dock and the prop wash against the rudder will be your friend.
Watch any busy commercial dock with crew boats tugs and other work boats maneuvering and you will see it over and over. Most boats will walk to some degree. Prop rotation plays a part as well. Inboard turning wheels walk much better that outboard turning wheels.
__________________
Advertisement

Sailor of Fortune is online now   Reply With Quote
Old 08-19-2015, 06:44 PM   #22
Guru
 
High Wire's Avatar
 
City: Cape May, NJ and Englewood, FL
Country: USA
Vessel Name: Irish Lady
Join Date: Dec 2007
Posts: 1,602
Quote:
Originally Posted by Bacchus View Post
One item mentioned that affects ability to do this successfully is prop position another that I have experienced that can have a major impact on success is whether your props are recessed in a tunnel. The larger the prop tunnels the less successful you will be... Tunnels reduce the prop walk affect.

Don
'08 MS 34 HT
"Bacchus"
Agree. My old Phoenix had prop tunnels and would not go sideways without significant throttle jockeying. It just was not worth the risk of a mistake.
__________________

__________________
Archie
1984 Monk 36 Hull #46
Englewood, FL and Cape May, NJ
High Wire is offline   Reply With Quote
Old 08-19-2015, 07:01 PM   #23
Scraping Paint
 
City: -
Country: -
Join Date: Oct 2007
Posts: 13,748
Quote:
Originally Posted by Edelweiss View Post
Real world you're probably going to approach the dock at minimal speed, with a bow "in" angle and then reverse the outside engine, maybe a little forward thrust with the other, to move the stern to the dock as you come to a stop.
The above description is how it works (and how we do it) with a boat with counter-rotating props with the port prop being a right-hand prop and the starboard prop being a left-hand prop

In the case of a final approach and docking to a starboard tie, with the outside (port) prop turning in reverse and the inside (starboard) prop turning in forward, both props will be turning clockwise so the combined propwalk will move the stern to starboard (toward the dock).

Putting the rudders over away from the dock (helm wheel in a port turn) the forward thrust of the inboard (starboard) prop against the rudder will add to the propwalk to move the stern even faster to starboard.

(Of course the bow will move to port when you do this because a boat pivots somewhere along its length, so you want to be pretty close to the dock when you initiate this or you'll end up with your stern against the dock and the bow drifting out away from it.)

If the approach and docking is a port tie, then the above control positions are reversed.

The fellow who first taught me to maneuver a twin engine boat gave me a great analogy which helped me remember how to manipulate the shifter levers to get the desired movement of the stern until it became second nature and I didn't need the analogy anymore.

He asked me if I'd ever driven an old-fashioned bulldozer (with lever controls for each tread, not a single joystick). I had so he said to imagine the boat the same way. With both treads shifted to forward, the tractor goes forward. With one tread shifted to neutral and the other in forward, the bulldozer makes an easy turn toward the unpowered tread. With one tread in forward and the other tread in reverse, the tractor pivots toward the tread that's in reverse.

So, he said, think of the shift levers as the tread controls and your butt as the back end of the tractor (boat).

My wife was taught a slightly different analogy, one that is probably even easier to envision. With her arms clamped tight against her sides and angled forward at the elbows, pushing her right arm forward twists her body to the left and her butt pivots to the right. If she pushes her left arm forward, her body twists to the right and her butt pivots to the left.

If she pushes one arm forward and pulls the other arm back her body really twists toward the arm coming back while her butt pivots a lot more toward the arm moving forward.

The boat reacts exactly the same way.

This is why a bow thruster is a great tool if you have one because it's the only way, single or twin, that you can move the bow straight sideways one direction or the other and leave the stern exactly where it is. We don't have a bow thruster and have gotten along okay without one, but there have been times when the ability to move the bow but leave the stern right where it was would have made things easier and faster.
Marin is offline   Reply With Quote
Old 08-19-2015, 07:04 PM   #24
Master and Commander
 
markpierce's Avatar
 
City: Vallejo CA
Country: USA
Vessel Name: Carquinez Coot
Vessel Model: 2011 Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 10,265
I have round fenders at the boat's "corners" for hull protection when leaving or arriving at dock at an angle.

With a single propeller and a bow thruster, sideways movement can be achieved with a bit of shuttling. When moving to starboard, the rudder is set to port and idled engine in forward gear while the thruster is set for starboard movement. Forward motion is reversed by changing to reverse gear.. Going to port is done with the opposite directions. With my starboard propeller walk, moving to starboard is easier since in reverse the stern tends toward starboard.
__________________
Kar-KEEN-ez Koot
markpierce is offline   Reply With Quote
Old 08-19-2015, 07:06 PM   #25
Guru
 
Sailor of Fortune's Avatar
 
City: Saint Augustine, Fl.
Country: Port of St Augustine ,FL
Join Date: Sep 2009
Posts: 1,969
Marin
The reason it is not working for you is you have your engines backwards. Stbd tside moor should be helm away (port, you have that correct) and stb eng reverse, port ahead, WITH SOME FWD MOMENTUM.
Sailor of Fortune is online now   Reply With Quote
Old 08-19-2015, 07:39 PM   #26
Guru
 
cappy208's Avatar
 
City: Cape Cod
Country: USA
Vessel Name: Slip Aweigh
Vessel Model: Prairie 29
Join Date: Oct 2013
Posts: 1,131
Moving boat sideways

True 'walking' sideways requires inboard turning wheels. To get a visual of how it works, Picture yourself standing behind your boat out of the water. (With inboard turning wheels). To walk to starboard you would use the port engine ahead and Stbd engine in reverse. The propellers would be turning clockwise( port turning inboard((ahead)) and Stbd turning clockwise ((astern)). The bottom of the wheels that are biting the water 'drag' the stern to starboard. The rudder is adjusted to the 'sweet spot' that keeps the bow approximately even with the stern. However the rudder on most yachts are not big enough to really help much.

What you are describing is not really waking, but just twisting and wiggling. Boats with outboard turning wheels do not walk but use the ahead engine with opposite rudder to overwhelm the astern engine. This results in not walking sideways but skittering diagonally ahead as you approach a dock.

True walking is directly sideways. Some boats will never truly walk sideways against the wind or current. (Excepting thrusters).
cappy208 is offline   Reply With Quote
Old 08-19-2015, 07:42 PM   #27
Guru
 
City: Satsuma FL
Country: United States
Vessel Name: No Mo Trawla
Vessel Model: Hurricane SS188
Join Date: Jul 2014
Posts: 1,681
Are you certain it wasn't a pod drive? They can move sideways and there is a Youtube video demonstrating it.
Donsan is offline   Reply With Quote
Old 08-19-2015, 07:55 PM   #28
Guru
 
Edelweiss's Avatar
 
City: PNW
Country: USA
Vessel Model: 1976 Californian Tricabin LRC
Join Date: May 2011
Posts: 1,834
Quote:
Originally Posted by cappy208 View Post
True 'walking' sideways . . . . . . . . . However the rudder on most yachts are not big enough to really help much.
What you are describing is not really waking, but just twisting and wiggling.
That is correct:

Unlike most single engine yachts and Commercial boats, most twin engine yachts use a small rudder (some exceptions noted). The spade rudder is fine for normal cruise speeds but has little effect at docking speeds. The engines are often used for maneuvering in tight spaces and marinas.

Since there is very little rudder surface to react against, the propeller side walk is greater than the wash against the rudder and the boat doesn't react as predicted. If that is the case and the wind or tide is pushing you away from the dock, you're unlikely to generate enough side thrust to push the boat back. Better off to back out of the slip and re-position for another docking attempt.
__________________
Larry B
Careful . . .I Have a Generator and I'm not afraid to use it !
Edelweiss is offline   Reply With Quote
Old 08-19-2015, 07:55 PM   #29
Scraping Paint
 
City: -
Country: -
Join Date: Oct 2007
Posts: 13,748
Quote:
Originally Posted by Sailor of Fortune View Post
Marin
The reason it is not working for you is you have your engines backwards. Stbd tside moor should be helm away (port, you have that correct) and stb eng reverse, port ahead, WITH SOME FWD MOMENTUM.
The docking maneuver Eidleweiss and I just described works perfectly for us and has for the 17 years we've owned the boat. It's how we do every single docking we've ever done, in fact. Maybe you're thinking of a boat with the opposite prop arrangement. But our boat has counter-rotating props with the port prop being a right-hand prop (turns counter-clockwise going forward) and the starboard prop being a left-hand prop (turns clockwise going forward). (photo)

So to move the stern to starboard you put the starboard engine in forward and the port engine in reverse. This causes both props to turn clockwise which means the propwalk from both props is in the same direction and moves the stern to starboard. At the same time, the port engine in reverse is exerting some leverage on the boat to "pull" the port side of the boat back while the starboard prop in forward is exerting leverage to "push" the starboard side of the boat forward, which creates a pivoting moment which, when added to the propwalk effect moving the stern to starboard, makes the whole boat pivot counterlockwise (viewed from above) even more smartly and moves the stern even more smartly into the dock on the starboard side.

Then if you add rudder away from the dock, the forward thrust of the starboard propeller against the hard-over rudder directly behind it moves the stern even more smartly to starboard.

If we did with our boat what you describe, we would defeat the maneuver because the thrust against the rudder would be countering the effect of the propwalk.

If you're talking moving the boat straight sideways for anything more than a couple of feet, that doesn't work no matter what you try to do. And having forward momentum sort of defeats the whole notion of moving the boat straight sideways into a tight spot anyway, right?

Quote:
Inboard turning wheels walk much better that outboard turning wheels
No they don't. Because when the thrust is opposed, both props will be turning the same direction assuming counter-rotating props. So one will be turning inboard and one will be turning outboard. Oppose them the other way, and one will still be turning inboard and one will still be turning outboard. So the amount of propwalk will be the same in either direction.
Attached Thumbnails
Click image for larger version

Name:	Props.jpg
Views:	70
Size:	115.9 KB
ID:	43328  
Marin is offline   Reply With Quote
Old 08-19-2015, 07:59 PM   #30
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,920
Both work...as many things in boating...there's more than one way to do it.
psneeld is offline   Reply With Quote
Old 08-19-2015, 08:10 PM   #31
Master and Commander
 
markpierce's Avatar
 
City: Vallejo CA
Country: USA
Vessel Name: Carquinez Coot
Vessel Model: 2011 Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 10,265
Those with both bow and stern thrusters must find this discourse amusing.
__________________
Kar-KEEN-ez Koot
markpierce is offline   Reply With Quote
Old 08-19-2015, 08:12 PM   #32
Guru
 
ancora's Avatar
 
Join Date: Dec 2007
Posts: 3,490
Those with bow and stern thrusters are not "boat handlers."
ancora is offline   Reply With Quote
Old 08-19-2015, 08:15 PM   #33
Guru
 
Capt.Bill11's Avatar
 
City: Sarasota/Ft. Lauderdale
Country: USA
Join Date: Apr 2014
Posts: 5,422
Quote:
Originally Posted by Sailor of Fortune View Post
Marin
The reason it is not working for you is you have your engines backwards. Stbd tside moor should be helm away (port, you have that correct) and stb eng reverse, port ahead, WITH SOME FWD MOMENTUM.
That's how I do it with boats up to say 100' to 110' or so. Not that you can't do it with larger vessels.

But I rarely have to put the inside engine in fwd at the last second to help pull the stern in with the out side engine in rev. In most cases I just come in with way on and turn the wheel hard, or close to it, over away from the dock and use momentum, the water flow over the rudders and the out side engine in reverse to pull the stern in. If you get it right the boat just settles slowly against the dock with no fwd or aft movement.

As to walking boats side ways straight away or to a dock with just the engines and rudders, some boats will and so won't. But it's very rarely necessary. And even in cases where it might be, I'd rather use a spring line.
Capt.Bill11 is offline   Reply With Quote
Old 08-19-2015, 08:20 PM   #34
Scraping Paint
 
City: -
Country: -
Join Date: Oct 2007
Posts: 13,748
Quote:
Originally Posted by Capt.Bill11 View Post
But I rarely have to put the inside engine in fwd at the last second to help pull the stern in with the out side engine in rev. In most cases I just come in with way on and turn the wheel hard, or close to it, over away from the dock and use momentum, the water flow over the rudders and the out side engine in reverse to pull the stern in..
That is generally the way we do it, too. Sometimes, however, depending on wind, current, etc., a shot of forward on the inside prop against the rudder is needed to get the stern up close enough to the dock so the person handing the deck can jump/step to the dock with the spring line.
Marin is offline   Reply With Quote
Old 08-19-2015, 08:21 PM   #35
Master and Commander
 
markpierce's Avatar
 
City: Vallejo CA
Country: USA
Vessel Name: Carquinez Coot
Vessel Model: 2011 Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 10,265
Quote:
Originally Posted by Capt.Bill11 View Post
... But I rarely have to put the inside engine in fwd at the last second to help pull the stern in with the out side engine in rev. In most cases I just come in with way on and turn the wheel hard, or close to it, over away from the dock and use momentum, the water flow over the rudders and the out side engine in reverse to pull the stern in. If you get it right the boat just settles slowly against the dock with no fwd or aft movement '..
So true, but some of us sometimes miscalculate our landings.
__________________
Kar-KEEN-ez Koot
markpierce is offline   Reply With Quote
Old 08-19-2015, 08:24 PM   #36
Guru
 
Hawgwash's Avatar
 
City: Sidney
Country: Canada
Join Date: Feb 2015
Posts: 2,265
[QUOTE=Marin;360334] But our boat has counter-rotating props with the port prop being a right-hand prop (turns counter-clockwise going forward) and the starboard prop being a left-hand prop (turns clockwise going forward). (photo)[QUOTE]

Marin.
Do you not have the LH/RH rotation backwards?
Looking from the stern and your picture shows it, starboard turns clockwise and is a RH prop. Port, LH, counter clockwise.

Or, said another way, starboard leading edge moves clockwise, to the right, going forward.
Hawgwash is offline   Reply With Quote
Old 08-19-2015, 08:30 PM   #37
TF Site Team
 
Baker's Avatar
 
City: League City, Tx
Country: Texas
Vessel Model: Carver 356
Join Date: Oct 2007
Posts: 5,633
Strangely, I do not even really think about it. I just do what works. ANd what works for me is what S O F and rardoin have explained. With that said, for the OP, you have to think of it as a "falling leaf". You are going to have a little bit of forward and reaward movement. Just a little. Because once it goes forward then you change direction and wiggle into the dock. There are people on here(Ksanders I believe) that claim they can walk their boat straight sideways. I would have to see it to believe it. There will always be some wiggling.

Current pretty much helps you in 3 directions. ANd hurts you in one(toward the dock if you are trying to get away...and away from the dock if you are trying to toward it). If the current is coming from the dock and you want to go toward it, THAT will be your biggest test on getting your boat to the dock. ANd it will also force you to be the most aggressive.
__________________
Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B
Baker is offline   Reply With Quote
Old 08-19-2015, 08:36 PM   #38
Scraping Paint
 
City: -
Country: -
Join Date: Oct 2007
Posts: 13,748
Quote:
Originally Posted by Hawgwash View Post
Marin.
Do you not have the LH/RH rotation backwards?
Looking from the stern and your picture shows it, starboard turns clockwise and is a RH prop. Port, LH, counter clockwise.
That's what I said. Starboard turns clockwise in forward when viewed from astern, port turns counter-clockwise in forward when viewed from astern.

Or put another way, when both props are turning in forward gear, the upper blades of each prop are moving toward the prop's side of the boat.

The way I was taught to determine if a prop is right or left handed is to squat down behind the the prop (looking forward at it) and if I reach out with my left hand and it lays flat on a blade on the left side of the wheel with my hand angled up and away from me, it's a left-hand prop. If I reach out with my right hand and it lays flat on a blade on the right side of the wheel with my hand angled up and away from me, it is a right-hand prop.

Which is how the props on our boat are oriented.

But even if I was taught the right-hand/left-hand determination incorrectly, this doesn't change the fact that I have the actual rotation and thrust generation of both props correct.
Marin is offline   Reply With Quote
Old 08-19-2015, 08:40 PM   #39
Guru
 
Sailor of Fortune's Avatar
 
City: Saint Augustine, Fl.
Country: Port of St Augustine ,FL
Join Date: Sep 2009
Posts: 1,969
Quote:
Originally Posted by Edelweiss View Post
Good idea!!

But don't expect the boat to just "jump sideways" to the dock, like a bow thruster. The effect on the bow is much less dramatic than the effect of moving the stern by counter shifting the port and starboard engines. In a perfect world, where there is no wind or tidal effect, the boat would glide to a stop parallel to the dock and allow you to take your time and walk it slowly in, but it's rare that you have those conditions.

Real world you're probably going to approach the dock at minimal speed, with a bow "in" angle and then reverse the outside engine, maybe a little forward thrust with the other, to move the stern to the dock as you come to a stop.

If you haven't already done so, before you practice docking you need to find the pivot point of your boat. It's probably a few feet somewhere behind your bow. (Mine is just ahead of the salon door.) Take your boat out on a calm day and find a buoy or a dolphin to use as a fixed reference point. Point your bow at it and put one engine in reverse and the other in forward. (The reverse engine will probably need a little more throttle to stop forward movement.) Note how your boat rotates around it's pivot point in relation to the reference point. That's your pivot point and knowing that will help you visualize how your boat will "probably" move when you approach a dock and apply different thrust techniques.

Now add wind and tide to that and all bets are off!!
Quote:
Originally Posted by Marin View Post
The docking maneuver Eidleweiss and I just described works perfectly for us and has for the 17 years we've owned the boat. It's how we do every single docking we've ever done, in fact. Maybe you're thinking of a boat with the opposite prop arrangement. But our boat has counter-rotating props with the port prop being a right-hand prop (turns counter-clockwise going forward) and the starboard prop being a left-hand prop (turns clockwise going forward). (photo)

So to move the stern to starboard you put the starboard engine in forward and the port engine in reverse. This causes both props to turn clockwise which means the propwalk from both props is in the same direction and moves the stern to starboard. At the same time, the port engine in reverse is exerting some leverage on the boat to "pull" the port side of the boat back while the starboard prop in forward is exerting leverage to "push" the starboard side of the boat forward, which creates a pivoting moment which, when added to the propwalk effect moving the stern to starboard, makes the whole boat pivot counterlockwise (viewed from above) even more smartly and moves the stern even more smartly into the dock on the starboard side.

Then if you add rudder away from the dock, the forward thrust of the starboard propeller against the hard-over rudder directly behind it moves the stern even more smartly to starboard.

If we did with our boat what you describe, we would defeat the maneuver because the thrust against the rudder would be countering the effect of the propwalk.

If you're talking moving the boat straight sideways for anything more than a couple of feet, that doesn't work no matter what you try to do. And having forward momentum sort of defeats the whole notion of moving the boat straight sideways into a tight spot anyway, right?

No they don't. Because when the thrust is opposed, both props will be turning the same direction assuming counter-rotating props. So one will be turning inboard and one will be turning outboard. Oppose them the other way, and one will still be turning inboard and one will still be turning outboard. So the amount of propwalk will be the same in either direction.
Marin
The last time this subject came up you swore that not boats can walk sideways. Your Coast Guard "expert" boat handler couldn't walk your rig so you pretty much discounted this maneuver as urban legend if I recall. Go to any port and see this as a routine manuever by thousands of boats and operators. Crew boats, supply boats and tugs (with barges) do this daily. I'm not going to argue if it works or not. Cappy and I are in the same business in a busy port that this is a routine operation. I'm not trying to convince you of anything other than your doing it wrong. If you get the results desired, great.
You arguing boat handling with me is like me arguing sentence structure with you.
Sailor of Fortune is online now   Reply With Quote
Old 08-19-2015, 08:44 PM   #40
Guru
 
Hawgwash's Avatar
 
City: Sidney
Country: Canada
Join Date: Feb 2015
Posts: 2,265
Talking about sideways, I watched a 70(?) Cheoy Lee come in today.
Skipper stood outside the wheelhouse door with a wireless remote smaller than my cell phone and brought that thing forward and sideways about 200 feet. The fenders didn't even squeeze as he settled it to the dock. He stepped off and secured it, Solo all the way.
So nice to watch.
Attached Thumbnails
Click image for larger version

Name:	Koolina.jpg
Views:	55
Size:	88.7 KB
ID:	43329  
__________________

Hawgwash is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 11:29 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012