In Part 1 we looked at how the effects of current differ from wind (a lot) and four simple cases.
Now let's look at some more difficult docking situations in current and confined spaces, and how we can still get alongside safely.
Our goals for this chapter and the next are:
- To build the fundamental skills to handle all the different situations we will be faced with in the real world, rather than try to cover every possible scenario, which would be impossible with all the variables in play.
- To learn how to identify docking-in-current situations that are a disaster waiting to happen, no matter what we do.
- To not get distracted by the details of the final approach and getting lines on the dock. We touched on that in Part 1 and will dig into it more deeply in Part 4.
In and Turn
To start off, imagine the berth we have been allocated is halfway down one of two parallel floating docks placed two boat lengths apart.
This is one Phyllis and I know well having spent two winters inside the Mega Dock at Charleston City Marina.
Given the distance we will have to cover from open water to the vicinity of our berth, the best strategy is generally to motor in forward, turn the boat, and then dock bow out to make it easier to leave.
As usual, we are assuming a right-hand propped boat and no bow thruster:
- If you have a left-hand prop, just reverse everything.
- If you have a bow thruster, a lot of this will be easier, but don't make the mistake of relying on it too much, since most yacht thrusters are pretty wimpy, particularly when put up against the power of current or a strong wind, and they can also fail unexpectedly, often, I gather (never had one), when the thing overheats and the thermal cut-out trips—could ruin your whole day.
Anyway, when faced with a difficult situation like this it's easy to flat line because it all seems so complicated and just blunder in hoping for the best, but that's an almost sure path to disaster.
We lost count of the number of times we saw boaters do just that in Charleston—we could tell because of all the confusion and shouting when it all went wrong.
We AACers know better...but only if we have carefully read the preceding chapters in this Online Book.
Before we even start the manoeuvre we need to break the situation down (as we learned in Part 1) into manageable pieces and figure out:
- Our turn using prop walk and prop wash, taking into account turn sidle.
- How far and in what direction to move the starting point of the turn to account for the current.
- How the turn will be helped or hindered by the wind.
Once we break it down like this, things get way simpler, and we can immediately see that there are only three ways to screw it up:
- Attempt the turn against the direction of the boat's prop wash.
- Misjudge the current strength and then compound the error by starting the manoeuvre from a position that leaves us no way to abort and try again—competent mariners always have a bail-out option.
- Forget to properly allow for the effect of the wind and so get into a situation where we can't complete the turn and will have to back out, which might be impossible depending on current, wind direction and the strength of both.
The first is easy to avoid as we have already learned:
- Right-hand prop: turn must be clockwise.
- Left-hand prop: turn must be counterclockwise.
We are going to leave wind out of it for a minute while we look at four current scenarios: