Anonymous
Anonymous asked in Science & MathematicsPhysics · 7 years ago

Why would ships at sea have a minimum passing distance between them?

Using Bernoulli's principle? Physics?

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  • rowlfe
    Lv 7
    7 years ago
    Favorite Answer

    The wake from the bow of each meeting in between causes a suction to draw the ships together. It is even worse if traveling side by side in the same direction. The water in between the side by side ships forms a trough and the ships literally slide downhill toward each other. This was a huge problem at night with the convoys in WWII. And yes, I believe this is the Bernoulli effect on a large scale as a result of the shape of the water surface between the sides of the moving ships. The ships effectively form a pipe moving through the water. The Bernoulli effect works on the relative motion between a fluid and a surface. Whether the fluid moves or the surface moves, you have the required relative motion to produce the effect. I was in the Navy for 20 years, and many times, when I was stationed on a destroyer, we refueled at sea. I actually SAW the effect of the moving water between the ships when I was on deck handling lines. The faster you go the harder it is to control the ships and maintain formation. I transferred to nuclear power and submarines after a few years of the surface fleet, so I never had to refuel at sea ever again...I don't know the math or the physics, but I know it works because I saw it firsthand...

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  • 7 years ago

    If you were ever somewhere by a river along which heavy ships move quickly, you would notice the effects that occur, both out in front and to the sides in front, even before the wake waves reach where you are.

    A heavy moving ship quite literally forces so much water about it to speed up, that ahead of it, the tide goes out! You can watch the water recede as its level drops.

    Then the ship passes. Briefly, the water rushes back, the water level rises somewhat beyond its "normal" level, before the wake waves arrive.

    It's a eye- opener to witness the effect on the huge mass of water in a wide river, and the extent of it!

    The same effect happens on the open sea. So 2 ships passing in the same direction especially, are forced towards each other by having fast moving water on one side that is common with the fast water on the opposing side of the other ship. These are essentially low pressure areas, and because they are moving fast, the lows combine on the opposing sides, and both are forced towards each other by the relatively higher pressure on their opposite sides.

    When steaming alone, the pressures each side are balanced. So as ships are not easily turned due to their mass, a minimum separation when passing is essential.

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  • 4 years ago

    The literal answer is, "so as that they won't collide." Having spent years at sea, a stable helmsman can function a 200 m long deliver, displacing countless thousand lots, interior of 20 meters of yet another deliver on a parallel direction going approximately 15 miles according to hour (yet at 20 meters, everybody in touch is slightly antsy). the respond that the instructor is in all possibility searching for is that there would desire to be a decrease stress zone midships, between vessels. that would tend to charm to ships closer mutually (merely like 2 trailer/tractors next to a minimum of one yet another on the line). yet another part is the the swifter the ships are shifting, the extra stated the end result. A problem is that as ships pass extra slowly, they're much less waiting to regulate their direction (they could have numerous water flowing previous the rudder to regulate the direction--a rudder loses effectiveness at decrease speeds).

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