Physics question thought experiment

[Zoot Allures]

Could you just heave anchors overboard on all sides of a boat to stop capsizing in a storm because the storm now has to lift up more weight?



In other words, would my idea make a boat less woobly?

Two different scenarios

1 the anchors do not reach the bottom

2 the anchors reach the bottom



Would size of boat make any difference ?


My thought is my idea would not work as the weight on one side negates the weight on the other

 

[shack]

Off the top of my head, I'd say that all four anchors would have to reach bottom solidly, but just barely such that the ropes to all 4 would have to be taut to keep the boat as stable as possible.

 

[Jenesis]

Could you just heave anchors overboard on all sides of a boat to stop capsizing in a storm?

In other words, would my idea make a boat less woobly?

Two different scenarios

1 the anchors do not reach the bottom

2 the anchors reach the bottom

I use two anchors for my boat so I can control direction when anchored. Especially when there are more than one person in the boat. This can ensure that we are turned in the right direction to be able to all fish the same direction. Like casting to shore for example.

With anchors, they have to be placed correctly, especially in rough weather. You need a longer line that runs more diagonal or the weight of the boat in the waves will just lift the anchor if it is straight up and down. I don’t know how you would do this with multiple anchors however. So I don’t know if this would actually work to stop a capsize.

 

[thumper18474]

Wouldn't a rogue wave that breaks take the boat down?
It needs to give with the direction of the wave..no?

 

[Zoot Allures]

Wouldn't a rogue wave that breaks take the boat down?
It needs to give with the direction of the wave..no?

Good point.

So , to uncomplicate the thought experiment, would my idea make the boat less woobly in calm water?

Pretend it is a row boat as that makes it easier to imagine

 

[Big Rig]

Good point.

So , to uncomplicate the thought experiment, would my idea make the boat less woobly in calm water?

Pretend it is a row boat as that makes it easier to imagine

This what me think

putting weight in middle of boat increases wobble

putting weight in middle of boat but under the boat decreases wooble

putting weights on side of boat should make no difference
so putting weights on side of boat but under boat should make no difference

Newtons laws would give a detailed explanation of the forces involved

I am unaware of any history of boats using your idea in a storm
so it must not work or they would have done it

They use idea from post 3 if anchor can attach itself to bottom

I use two anchors for my boat so I can control direction when anchored.
With anchors, they have to be placed correctly, especially in rough weather. You need a longer line that runs more diagonal or the weight of the boat in the waves will just lift the anchor if it is straight up and down

 

[thumper18474]

Anyone watch the perfect storm?
When they decide to head back and they drop the "birds"?? in the water...or whatever they were... was that to stabilize cus they were bottom heavy with the fish in the gold..and prevent the boat from rocking too far...Port or Starboard?
Always wondered that?

 

[Ceiling Cat]

You would have to carry that may anchors all the time. If the ship is rocking and rolling, you would not know which side to throw the anchor over.

 

[Zoot Allures]

You would have to carry that may anchors all the time. If the ship is rocking and rolling, you would not know which side to throw the anchor over.

as the boat is rocking both ways you put anchors all around


to uncomplicate the thought experiment, would my idea make the boat less woobly in calm water?

Pretend it is a row boat as that makes it easier to imagine

 

[Zoot Allures]

Anyone watch the perfect storm?
When they decide to head back and they drop the "birds"?? in the water...or whatever they were... was that to stabilize cus they were bottom heavy with the fish in the gold..and prevent the boat from rocking too far...Port or Starboard?
Always wondered that?

To make your boat more stable, you can add ballast to the bottom of the boat to increase its weight.

 

[PeterStar]

No. Anchors prevent a vessel from drifting. They do not prevent them from capsizing.

 

[261252]

No. Anchors prevent a vessel from drifting. They do not prevent them from capsizing.

That is my thought as well but something should work

weight put directly under the middle of the boat might work

 

[Telebass]

That is my thought as well but something should work

weight put directly under the middle of the boat might work

Sounds a lot like a sailboat keel. Doesn't really work.

Cruisers at anchorages have used weighted flat (horizontal) boards (so they sink) dropped from either side of the boat using the boom swung out on one side and the spinnaker pole on the other to provide better leverage. The sophisticated ones have a hole with a flapper in the middle so it sinks faster than it lifts. The idea is that the water resistance slows the roll. Too much hassle for me, but whatever lets you get some sleep.

 

[Zoot Allures]

The sophisticated ones have a hole with a flapper in the middle so it sinks faster than it lifts. The idea is that the water resistance slows the roll. Too much hassle for me, but whatever lets you get some sleep.

Thx

Interesting concept that makes sense

Someone thought outside the box

 

[Mr Deeds]

No. Anchors prevent a vessel from drifting. They do not prevent them from capsizing.

Exactly anchors won't steady a boat even if they do reach the bottom. Adding weight to the bottom such as a keel on a sailboat does steady the boat and will prevent capsizing. Large cruise ships have wings below the waterline to minimize rocking.

 

[SchlongConery]

Could you just heave anchors overboard on all sides of a boat to stop capsizing in a storm because the storm now has to lift up more weight?

In other words, would my idea make a boat less woobly?

Two different scenarios

1 the anchors do not reach the bottom

2 the anchors reach the bottom

Would size of boat make any difference ?

My thought is my idea would not work as the weight on one side negates the weight on the other

Yes and no.

Yes, they will reduce dynamic rolling motions.

For centuries, mariners have used weights, diving planes/fins and various designed one-way discs extended out the sides with outriggers to reduce the rolling motion of boats and ships.

They are variously referred to as 'roll stabilizers'. Here is one brand called "Flopper Stoppers" https://www.boatstabilisersaustralia.com/

No, they likely won't stop the vessel from being capsized at anchor if broadsided by a huge gust of wind or huge wave. They use the resistance force of the device against the mass of the water. Not weight. The plates are sort of one-way valves to provide asymmetrical upward resistance against the direction of rolling motion. They are more stabilizers than lateral anchors.

The flat plate area of the keel of the ship provides lateral hydrodynamic damping to attenuate rolling motions at anchor..

The ballast at the lowest points possible in the vessel is what not only provides resistance against capsizing by lowering the centre of gravity and the centre of buoyancy. The ballast in the keel also provides mass to right the vessel if, and after the vessel has been capsized. The lower the C of G, the more stable and the more effective the 'righting moment'.

Putting tonnes of lead in a bulb/torpedo shape at the very end of the keel is much more effective than anything. The longer and heavier the keel and bulb the better. And the taller the vessel, the more keel and ballast is required for effective high wind sailing and knock down protection. But in sailing boats, the keel and ballast is calculated for actual sailing. Winds, sail size/sail plan, height of mast etc are orders of magnitude greater than the forces encountered at anchor required for a knock down.

Here is a demonstration.