I just love this picture: The two boats in the front are going at the same speed (the trainer is driving right next to the person in the row boat over a long distance), yet look at how different the two ships’ wakes look!
The motor boat has this huge, breaking, turbulent wake. Even though it rides so high up in the water, it displaces a lot of water and creates a wake with a large amplitude (how large the amplitude is is visible in the picture below, where some poor people were sitting in row boats when a motor boat sped past. But also here: Look at how cool these feathery waves that constitute the wake look together!).
But then, going back to the original picture (which I am showing again below) — look in contrast at the row boat’s wake. You see the paired eddies where the oars were in the water, and you see a tiny little trail where the body of the ship went. But that’s all. Yet both boats are going at exactly the same speed! Pretty cool, isn’t it? (Also pretty scary how much energy the motor boat is spending on moving water and moving a larger hull and a heavy engine rather than just propulsion when the payload of both boats is more or less the same — one person)
You know how they say that the journey is the destination? That was certainly the case for my spontaneous mini-vacation yesterday (and how awesome is it that my #BestTravelBuddy is up for a cross country trip on a day’s notice?). We went all the way from the east coast to the west coast — which in Germany admittedly isn’t that terribly far — to visit the island Sylt in the North Sea for a day.
But it got even better when we reached the west coast. This is my kind of train ride!
Below is a view of the dam that connects the island Sylt with the main land, and here again you see how windy it is, and this is in the lee of the island. In the lee of those shallow dams you see that it really doesn’t take long for the surface roughness to increase again.
So are you excited to see the wind-ward side of the island now? I’ll post some wave watching from that side soon, but I first have to wade through literally thousands of pictures to cut it down to a handful. I’m already down to about the 100 best, but now I can’t decide which ones to post, because I like them all…
But here is a picture of the train ride back. Do you notice how there are regions with really low surface roughness on either side of the dam, suggesting that this dam is sheltering the water surface from the wind in two directions? Of course it isn’t — it’s just ebb tide and the smooth surface areas towards the right of the dam are wet sand that look similar to a smooth water surface.
So that’s my wave watching from the train! Excited to go back soon! :-)
Have you ever noticed how much you can observe when you look at water from a distance? For example in these pictures, you see the tracks of ships that are long out of sight! Do you see the circle that one obviously drove before leaving our field of view?
For the ships far out in the fjord, you can’t actually see the waves so much as the turbulence they created that left the surface smoother, thus better reflecting the light from the low sun (and appearing yellow-ish). And how cool how you see how newer tracks run over older ones! Only for the ferry in the bottom left you can actually see the waves themselves.
In the picture below we actually see the waves that both ferries made.
Zooming in: How cool does it look to have these waves almost all the way across the water? And do you see how they are bound by the ship’s V-shaped, feathery wake? I find it really fascinating that there are such large surface elevations, but only inside of the ship’s wake.
I just love wave watching, even when I am not even that close to the water :-)
Beautiful morning arriving back in Kiel… Looking downwind, the weather might seem pleasant (especially when focussing on the sunrise).
But looking upwind however, the wind rows on the water as well as the white caps on the waves indicate that it’s quite windy!
Very cool: the turbulent wake of a ship interrupts the wave field and therefore, with its different surface roughness, is clearly visible!
And below you see so many things: The sand bank running from the lighthouse towards the next headland becomes visible as waves are breaking on it. The turbulent wake of that blue ship we saw above already is still clearly visible, as is its V-shaped wake. And you see our own wake as the feathery pattern that runs all the way from the bottom edge of the picture to way behind the blue ship!
And here our own wake becomes even more prominent as we turn. Laboe in the background…
Here is another ship, waiting to enter the locks of the Kiel canal. It’s moving only very slowly (so hardly any wake visible), but you see how it’s sheltering the water from the wind so the downwind water appears completely smooth right at the ship!
And here are some more wakes and sheltered spots of water surfaces. Locks of the Kiel canal in the background!
And another look at the locks. Do you notice how the wind rows still indicate that it’s quite windy, but how it’s a lot less windy than it was further out?
And then we are in the Kiel fjord. This is the upwind shore — see how waves are only slowly forming and building up with longer and longer fetch?
And then in the sheltered port a different kind of waves: Our bow propellers mixing the inner Kiel fjord!
Wave watching from high up gives you a whole new perspective on wakes, and depending on the lighting, features in the wave field become more prominent or fade away.
See for example below the ferry: You very prominently see the turbulent wake right behind the ship, and you see the waves of the wake opening up in a V-shape.
Above, there is still a lot of ambient light from the sky. Below though, the same ferry, similar spot, 30 minutes later: The turbulence is a lot harder to see since colors fade away, but the V-shaped wake becomes really clear since one slope of the waves reflects the city’s lights while the other reflects the darkness.
Another ferry coming in, another wake… Below the surface roughness becomes clearly visible with the turbulent wake right behind the ferry and the bow waves fanning out.
That was one brilliant mini cruise! Thanks for joining me, Frauke, and for staying out on deck with me — despite the freezing temperatures — until we were far out of the port and the light was gone completely. The sacrifices we bring in order to wave watch… ;-)
Having a bulbous bow alone does not always lead to the same bow wave. Which is fairly obvious when you think about it, of course the speed of the ship or the shape of the bow influence the wave field that is created, but also how heavily the ship is loaded, i.e. how deep the bow is in the water.
What you can see very nicely on the sequence of pictures of bows and bow waves in this post are bulbous bows going from fairly far out of the water (above) to fully submerged (towards the end).
And I just love the sharp contrast of the smooth water piling up and then the turbulence and breaking waves right there. Interesting example of subcritical and supercritical speeds, btw: The ship travels faster than the bow wave (so the bow wave can’t overtake the ship, but always stays behind it, forming a two-dimensional Mach cone).
The ship in the picture below is the odd one out in this blogpost: It does not have a bulbous bow but just pushes water in front of it. This is an interesting example of a bow shape that is clearly not optimized for energy efficiency when traveling large distances, but then the purpose of that ship is obviously a different one. But isn’t it amazing how such a small ship creates waves larger than all the other much bigger ships do, just because they have better bow shapes?
But beautiful wakes nonetheless. I love those tiny ripples riding on top of the wakes!
And, of course, the checkerboard pattern of a wave field and its reflection.
Here is another example of a ship with a bulbous bow, this time it is almost submerged. Since they are designed to be fully submerged, this ship is loaded in a way that is closer to what it was made for, and you see that the generated waves are smaller than the ones in the pictures up top.
And look at its wake — really not a lot going on here, especially when compared to the much smaller ship a couple of pictures higher up in this post!
Now for a ship that is hardly creating any waves at all, the mountain of water that it’s pushing in front of its bow looks especially weird since the bulbous bow isn’t visible any more.
See? (And isn’t it cool how the chronological order of pictures in this post just coincided with ships laying deeper and deeper in the water? I love it when stuff like that happens :-D)
And then, of course, I had to include some more pictures of beautiful wakes…
Do you see, comparing the picture above and below, how the first one was taken when the wake had just reached the shore, and the second one the wake was reflected on the shoreline already?
Not many things make me as happy as wave watching :-)
P.S.: Ok, one last bonus picture (non-chronological, we saw it some time during the walk. But that’s ok, I wasn’t going to include it until the post was already done and I decided that you just HAD to see this): Someone who is clearly not using their bulbous bow to their advantage. But at least I get to show you what they look like when they are not in the water. And we got to speculate about how annoying it is to be on a ship with such a strong tilt all day :-D
Let me tell you the story of the picture below. I was walking along Kiel fjord with some friends and we saw this mama duck with all those tiny cute ducklings. We stopped and oooo’d and aaaaa’d and they were just so adorable!! But the after a while they swam on and we continued walking. But then there were people standing on the sea wall, obviously very worried about something. And then we saw it: a tiny duckling that had gotten separated from its family! It was struggling so hard to catch up with the rest, but they were swimming together while the little one was trying to climb over the rocks along the sea wall! The distance grew larger and larger. People started cursing mama duck for leaving the little one, or were pleading with her to come back for the poor baby. And then mama duck started heading out into the open fjord, where it was a lot more windy and wavy. How should the poor baby ever catch up? Eventually mama duck turned back. But she didn’t spot the baby! They all swam in the wrong direction away from the baby! It was dramatic. The crowd on the promenade was agitated. People were heading towards the ladders to climb down and rescue the baby! Then, finally, mama duck and all the siblings came back. Baby duck sprinted back to its family and finally everybody was reunited. Phew! The crowd wasn’t quiet ready to leave, not quite trusting mama duck that she wouldn’t abandon baby duck again. But then we decided that we had seen the happy ending, the scar hadn’t hurt for 20 years and all was well.
The reason I am telling you this story? Because I am still fascinated by wakes of ducks. And I saw really beautiful ones this morning:
The structure inside of the legs of the V is clearly visible.
And what’s even better: you can see the pattern on the sea floor, too!
The more I observe waves, the better I get at noticing details that were probably always there but that never stood out to me as clearly as they do now.
That’s why I am so happy about having started this blog — it helps me observe so many amazing things :-)
Oh, and if you are still waiting for the wake? Sorry, this was it. I was obviously talking about waves :-)