Well, here we are again. Welcome to part 4 of 7 in the series Elements of Close Quarters Maneuvering.
So far, we have discussed analyzing wind and current prior to approaching the slip, the transmission position and why neutral is our friend, as well as the throttle and its horrible ability to take us to the insurance claim. Today, we will look at our general direction and why we need to determine our immediate goal of direction.
Remind me, what is Advance and Transfer?
If you recall, I introduced the notion of advance and transfer in our last conversation about close quarters maneuvering. As a review, advance is the boat continued forward progress in it’s original direction as it progresses through a turn, and transfer is the distance the boat travels laterally until it is established on it’s new course.
Generally, when we are executing a back and fill turn (standing turn to sailors) we want to minimize both advance and transfer. In other words, we would like to pivot the boat in place without making any forward, reverse, or lateral progress. In a no current no wind scenario we would progress down the fairway, center the pivot point of our boat, rotate, and then pull into the slip. Yeah, that happens in Disneyland, but rarely in our world.
In the event that there is wind or current impacting us as we are trying to get into our slip, and when isn’t there, we can use advance and transfer to our advantage. There are times when it is advantageous to proceed in a relatively straight line as the boat is rotating to its position to maneuver into the slip. This is particularly true if we want to enter the slip stern first.
Step-by-step Application Example
Let’s take a look at an example. With the boat proceeding forward, the wind on its stern, and the slip to port the best option may be to start rotating the bow to starboard about a half boat length prior to arriving at the first outboard piling of the slip. This piling will ultimately be the starboard bow piling.
As the boat proceeds forward put the transmission into reverse at idle speed and move the helm to full starboard. By rotating the helm to full starboard we can accomplish two things. First, if we need to create additional rotation we are ready; simply move into the second step of a back and fill turn (see part three of this series to learn more about back and fill turns). Second, if we need to “squirt” the stern to port a little to clear the piling, that can be accomplished by applying forward throttle for a very short duration (AND I DO MEAN VERY SHORT, like a quarter of a second) and returning to reverse idle; the boat’s stern will lunge to port six inches to a foot, and move forward just a few inches.
With the transmission in reverse and the throttle at or near idle forward progress, advance, will continue and prop walk will start to drag the stern to port. Add and remove throttle as necessary to increase or decrease the rate of rotation due to prop walk. The goal is to have the stern barely clear the first piling.
As soon as the stern clears the piling, increase power slightly to stop all the boat’s forward motion and start to move in reverse.
With the boat now making way in reverse, turn the helm to port to start steering the boat into the slip. The bow may not swing fully inline with the slip. If this is the case, allow the boat to come to rest on the leeward outside pile. Once gentle contact is made, by shifting back to reverse and adding a little power prop walk will again come into play and the boat will pivot on the pile. This pivoting will cause no damage to the boat and as the pivot is complete by reducing power the pile will push the boat to windward and the boat will be clear of the pivot pile and will travel back into the slip. With proper crew placement and fender patrol (crew carrying a fender and placing it between the boat and the piling) this maneuver can be performed without using spring lines. If there is no piling present the pivot can be accomplished on the corner of the dock. Care should be taken to assure a fender is lowered into place if the dock corner is not padded.
In the example above we utilized advance to our advantage and minimized transfer, but what if we had the slip on our starboard side. What then? Well, now we have a problem. We do not have the ability to utilize prop walk in this case. And, if we try to back down the fairway, the wind now on the bow, so that we can use prop walk, the bow will be blown around by the wind.
Furthermore, if the finger pier is on the upwind side of the slip we have an even more complicated entry. This entry; starboard side with wind blowing down the fairway, off the finger pier; is the most difficult slip entry there is. Our choices here are very limited. You know, some times all of the options suck and this may be one of those times.
Probably our best option, if we have good knowledgeable crew, would be to warp the boat into the slip, but we haven’t talked about warping yet so let’s forget that option.
Option # 1
Bow first. I like this choice because it allows us to make progress into the wind, stern first. Here’s how I would do it. Proceed down the fairway as in example one except favor the starboard side. As the boat reaches the windward outer pile, shift into reverse with a little throttle. Doing this will stop forward motion (advance) and start prop-walk.
As the stern of the boat starts to rotate to port the boat will start to move backward. This backward motion will hold the boat on station against the wind while it is rotating. When the maximum rotation has been achieved rotate the rudder to full starboard as you shift into neutral, pause briefly, and finally shift to forward with significant throttle. It is critical that the significant throttle be maintain only for a brief period of time. We want to lunge the bow to starboard, not move the boat forward (maximize transfer and minimize advance.)
When the lunge is complete return the throttle to idle or near idle. This allows the boat to progress forward into the slip. At the same time bring the helm to a slightly starboard position to allow the boat to make progress toward the finger pier where crew can step off making fast an aft spring-line from mid-ship.
As the crew step off, turn the helm away from the dock. With the aft spring-line made, continue to steer away from the dock in forward idle. Prop-wash will bring the entire boat along side the finger pier where crew can properly secure her.
Option # 2:
Stern first: This maneuver requires that the boat enter the slip in reverse utilizing significant power. It goes against everything we have spoken about so far in this series. You should only do this if you are on a first name basis with your insurance adjuster.
In this method the boat is brought down the fairway bow first favoring the starboard side. Continue past the slip two or three boat lengths. Shift to reverse with a little throttle. The goal here is to get water flowing past the rudder as soon as possible to overcome the prop-walk. With this slight throttle the boat will start making reverse way into the wind. While maintaining the reverse way steer into the slip.
The hazard with this method is obviously the considerable amount of way the boat is making. There is a lot of momentum driving us into the slip and toward the finger pier. There has to be to push against the wind. You MUST be ready at any moment to shift to neutral, set the helm to whatever position you deem necessary, and then shift to forward to stop all of the unwanted momentum the boat has developed.
This is really risky and should only be considered as a last resort. You know, there’s always another option, it just may be inconvenient. Be inconvenienced, this method is just not worth the risk. It will turn you from a hero to a zero in about three seconds. In fact, forget you read about it.
Option # 3:
Call the dock-master and ask for another slip assignment: Keep in mind that you only look like an a#%hole when you hit the dock. Your insurance company, and marina neighbors are counting on you to know your limits. If you’re not sure of them, now is not the time to find them. Simply call the dock-master and explain the situation and ask for another slip with a less challenging entry. He will be happy to help.
Option # 4:
Ask the dock-master for multiple hands to receive lines: With the land-side help in place proceed down the fairway favoring the port side. Pass the slip and execute a back and fill turn (standing turn to you sailors). Have crew ready on the port side of the boat with dock-lines; stern, mid-ship, and bow; in hand, coiled and ready to throw. Execute prop walk to bring the stern into the slip. The bow will blow downwind. The dock-hand handling the bow-line will wrap the it around the outermost pile or cleat and be able to control the bow with that line as the boat reverses into the slip.
Me, I like option #1, 3, and 4. Option #2 sucks, period. Practice makes perfect and if you never push against your limits they never will expand. Just remember, it’s one thing to push, and quite another to steamroll. Don’t steamroll!
I always look for the hard way to enter a slip. I do that so that when it really is a tough entry it won’t seem that bad to me. In other words, I practice all the time. So should you. Till next time, I’ll see you On the Water…With Captain Frank
Welcome to the third of seven articles about close quarters maneuvering. So far we have learned to wait and observed the wind as well as to use neutral as the primary transmission position. Today we will take a look at the third element mentioned in part one.—throttle position.
How much throttle and throttle position.
In general it is important to use as little throttle as possible when in close quarters. The addition of the throttle (adding power) results in increasing the boat’s momentum. The only time this is not true is if power is added to stop or slow the direction the boat is currently moving. Even then, the throttle very quickly goes from decreasing momentum to adding momentum, in whatever direction the shifter and helm are in and the results are very unpredictable.
People have the tendency, when they are frightened, to either do more of whatever they are doing or to freeze. That means that if they have just added power and the result is not what they expected they would tend to add more power or they would fail to remove the power they added. Neither of these scenarios is good.
If you remember from the first two parts in this series, the goal should be to always need to add more momentum to the boat, not try to take it away. Adding power without thoroughly thinking it through will usually result in the boat having too much momentum and then we are left with the dilemma of trying to dissipate that momentum with very little space around the boat.
With the exception of exceptional wind and or current, idle speed will get the job done. It might take a few more cycles of reverse and forward, but moving in close quarters should not be a race. Back and fill turns (standing turns to you sailors) work just fine at idle speed. As discussed in part two of this series, single inboard engine sailboats will need throttle added to compensate for their small engine and propeller size.
Understanding advance and transfer.
So, in close quarters, when is it okay to add power? Now there’s a good question! To understand the answer there are some things we need to know. Every turn made on a boat, no matter what speed we are traveling, involves two components. These components are called advance and transfer. Advance is the distance that the boat travels (regardless of what direction the bow is pointing) in the original direction before a turn was started. Transfer is the distance laterally (sideways) the boat has moved until it is established on its new course.
(Click on figure 1 to display in new window). Obviously, in close quarters we want both of these to be minimal. We would like the boat to simply pivot (no advance and transfer) from the original heading to the new heading. The only way that is possible is if warp lines are used to execute the turn or the boat is lying against a pile, using it as a pivot point. (see part seven of this series when it is published.)
Any time the boat is moving, in any direction, it has momentum. I think it was Newton that told us that a body in motion tends to stay in motion. So, if a boat is traveling forward and is then turned, the boat will still tend to travel forward as it makes the turn—advance.
However, if the boat is stationary and the helm is turned hard over in the direction of the desired turn and then shifted into forward (or reverse for directed thrust boats) there will be a brief period of time, just a couple of seconds, that the initial thrust of water against the rudder will lunge the stern of the boat in the opposite direction that the helm is turned–transfer. That period of time will quickly end and the advance of the boat will begin. In most instances idle power will be enough to get the turn done.
If there are strong winds and or current it may be necessary to add a judicious amount of power to combat those conditions. It is critical to add that power as soon as the transmission is engaged and to remove that power as soon as forward or reverse motion is detected. That means that the power is added for no more than a couple of seconds!
This action will maximize the transfer and minimize the advance. Be prepared for the stern to lunge in the direction opposite the helm and for the bow to turn in the direction we want to go. It is also critical to remember where the boat’s pivot point is. On keel sailboats that point is directly over the keel. For power boats of all types that point is 25-30 percent forward of the stern. Here lies the first hazard of adding power.
If the stern of our boat is NOT clear of the dock, pilings, or other boats the power added will drive the stern into those objects. NOT GOOD! If the helm is not pointed in the direction we want to go BEFORE the transmission and throttle are engaged the stern will not lunge in the direction we want. It will lunge in the direction opposite the helm position. If we delay in adding the power then advance will not be minimized. It is easier for the boat to advance then transfer. By adding power immediately we force the boat to twist in the turn rather than move forward. This advantage only last for a few seconds before the boat starts its advance.
Throttle and twin-engines.
Let’s talk about twin-engine propulsion systems. I know that most people that have not had formal instruction get behind the helm and when in close quarters split the engines (operate one engine in forward and the other in reverse). I also know that they start adding power to one or both (YIKES) engines. I’m here to tell you that sooner or later this will result in an insurance claim. Before they know it they have both engines running at about 5,000 RPM. The water gets so full of air and turbulence that the boat loses buoyancy and may sink! (Okay, the last sentence was a little over the top, but my point is made.)
There is no need to have both engines engaged at the same time, other than being impatience. Sure we should split the engines, but only one engine should be engaged at a time; and that engine should be at idle speed. Twin-engine inboard boats rely on the asymmetric thrust (the engines not being near the center-line of the boat) to reap the close quarters maneuvering advantage. By always engaging the out-board engine during a turn the boat is able to pivot around the stern corner of the boat on the inside of the turn. Remember, if we want to rotate the boat to port then when in forward the port stern corner is on the inside the turn and the stern is pivoting counter-clockwise, but when in reverse, the starboard stern corner is on the inside of the turn and the stern is still rotating counter-clockwise.
Generally no helm or throttle inputs are necessary. If there is strong wind or current than throttle may be required, but only for the part of the turn that involves pushing the bow into the wind or current. When pushing the bow into wind and or current the cycle of shifts should be rapid. Always pause in neutral between shifts, but don’t delay. Once the bow is being pushed downwind or down current then only idle speed should be used.
If our twin-engine boat has directed thrust than all of the above still applies but the helm should be swung from side to side just before we shift from forward to reverse or vice-versa. It is advantageous to swing the helm since twin outboard engines are generally located much closer to the centerline of the boat—affording less leverage. Always get the helm hard over prior to shifting into gear and or applying power. Always complete the helm swing with urgency while in neutral. We are trying to build twisting momentum and the longer we delay between shifts the longer the wind and or current have to stop our momentum.
A practical example of throttle position.
Let’s look at an example (click on figure 2 to open in new window). Joe is on a single engine inboard trawler with a right hand prop (prop rotation is clockwise in forward). He wants to leave his slip and turn to starboard into the fairway. He is stern into the slip. Joe’s first move after releasing all of his lines is to clutch (shift) into forward at idle speed. He does this just long enough to get the boat moving forward; then he shifts back to neutral.
He has his helm basically neutral although he steers slightly as needed to keep his boat going straight, avoiding the dock and piles. As soon as the boat’s stern will clear all obstacles Joe moves the helm to full starboard then clutches to reverse for a few seconds. This action will induce prop walk, the tendency for the prop to pull the boat’s stern laterally in the direction of prop rotation, and the stern will be pulled to port swinging the bow to starboard. This shift to reverse has the added benefit of stopping the remaining forward momentum. He now shifts to neutral and pauses. Leaving the helm to starboard he next shifts to forward. The prop is now pushing a wall of water at the rudder, which is still hard to starboard. He has added prop wash (water washing against the turned rudder) and the boat will continue its rotation clockwise–starboard. Next, he shifts back to neutral, pauses to evaluate his rotation, and then back to reverse. He continues this cycle until the bow is pointed nearly at his desired heading—approximately 90 degrees to starboard. Now he simply drives down the fairway.
If there was wind from the starboard side he may need to add some power to each of the above steps (click on figure 3 to open in new window). The power added will accentuate prop walk–a good thing in this case. In forward the added power increases prop wash; more power means more water against the rudder and therefore more twist, but it also means more advance—something he DOES NOT want. The power added should be immediate, fast, and very short lived.
If there was no wind or wind from port then there would be NO need for any added throttle. He would need to repeat the cycle of shifts more times when trying to push the bow into the wind or current.
Truth be told, if there were that much wind Joe would be much better off coming out of the slip and turning to port, downwind, and back out the fairway with his stern to the wind.
Just a couple of notes:
- Adding power always results in advance (regardless of forward or reverse)
- Adding power always increases momentum. In the case of turning, only part of that momentum is in the direction that you want.
- Power maybe necessary in the following instances:
- Pushing the bow into the current or wind
- Single engine inboard keel sailboats
- Momentary power may be necessary in the following instances: a. To increase the rate of turn (decrease the radius)
- When in close quarters we want to decrease advance and transfer
- Proper helm position along with judicious power can help to lunge the stern of the boat past an object such as a piling or dock corner
- Proper helm position along with proper transmission position can move the stern of the boat closer to the dock enabling a crew member to step off the boat
- Props and rudders are much more effective in forward than reverse
- Prop walk cannot be wished away. However, by NOT using throttle we can minimize it and by using throttle we can maximize it. Be sure to contemplate this before you do it.
- As mentioned in part one and part two remember that as you are maneuvering the boat, wind and current are still pushing you in their respective directions.
- Practice these techniques in open water first. As you master them move into increasingly tighter quarters.
- Power adds momentum. If contact with surrounding obstacles is going to occur then more momentum always makes more damage. STAY OUT OF THE THROTTLE
The best way to develop and master knowledge of throttle position and all of these skills is with me! On the Water…With Captain Frank