Uricanejack
Well-known member
Not inertia. While Inertia may have an effect. The main reason the boat rolls faster is the change in the centre of gravity.
The weight of the Mast is relatively high, it acts at the masts centre of gravity so a small g. Probable close to half way up the mast. Under normal conditions this weights position raises the boats centre of gravity a G.
The boats stability is a combination of the effects of its centre of G acting down and it’s centre of buoyancy acting up.
They want to be in line. incline the vessel and it will create a righting lever to bring the vessel back upright provided they are both in line.
The lost of the mast. Will do two things. If lost overboard, the weight is gone, the weight of the boat will be less it will float higher the center of buoyancy change to a position slightly lower.
The loss of the weight high up will cause the overall boats center of gravity to be quite a bit lower.
This lower centre of gravity will creat a larger righting leaver when the boat is inclined or heeled resulting in a faster more sudden return to upright.
The boat will be more stiff.
The change in stability is often expressed by comparing a theoretical position Metacentric height with the center of gravity.
Or GM
The GM will get quite a bit larger with the loss of the mast and rig.
M is a theoretical position on the centre line through which a vertical line up through the centre of buoyancy acts when the vessel is slightly inclined.
The centre of buoyancy moves to the low side when the vessel is inclined.
Sail boats are generally kind of stiff. Take the mast of they get a lot more stiff. So without the mast a sailboat will tend to roll faster and more violently than with the mast.
The weight of the Mast is relatively high, it acts at the masts centre of gravity so a small g. Probable close to half way up the mast. Under normal conditions this weights position raises the boats centre of gravity a G.
The boats stability is a combination of the effects of its centre of G acting down and it’s centre of buoyancy acting up.
They want to be in line. incline the vessel and it will create a righting lever to bring the vessel back upright provided they are both in line.
The lost of the mast. Will do two things. If lost overboard, the weight is gone, the weight of the boat will be less it will float higher the center of buoyancy change to a position slightly lower.
The loss of the weight high up will cause the overall boats center of gravity to be quite a bit lower.
This lower centre of gravity will creat a larger righting leaver when the boat is inclined or heeled resulting in a faster more sudden return to upright.
The boat will be more stiff.
The change in stability is often expressed by comparing a theoretical position Metacentric height with the center of gravity.
Or GM
The GM will get quite a bit larger with the loss of the mast and rig.
M is a theoretical position on the centre line through which a vertical line up through the centre of buoyancy acts when the vessel is slightly inclined.
The centre of buoyancy moves to the low side when the vessel is inclined.
Sail boats are generally kind of stiff. Take the mast of they get a lot more stiff. So without the mast a sailboat will tend to roll faster and more violently than with the mast.
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