- #1
sbg
- 12
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Hi everyone, this is a real world problem following the sinking of a narrowboat in 2014. The boat caught on the side of the lock as the water level dropped, and the resultant combination of pitch and heel resulted in the boat taking on water at the stern and sinking - luckily with no loss of life or injury. Without giving too much away (as the owner has settled the case with the navigation authority) I can offer the following information:
- boat length 60'
- boat displacement 15 tons (steel construction)
- The snag occurred on the port side, 10' from the bow
- Narrowboats tend to sit lower at the stern than at the bow so the CoG is probably aft of the centrepoint (Assumption - is this true?)
The boater stated that the water level dropped "a few inches" then later stated that the sinking actually occurred when the level had dropped by 2'. A few maths wizards have suggested that a 2' drop at the stern would equate to 2 degrees of pitch which seems a very small amount to me, and I'm pretty sure my boat (about the same size) rose by a couple of degrees at the bow just by having an empty water tank... I also think that my boat going up the slipway took on more than a 2 degree pitch
I'm not trying to make the boater look bad, and am in no way connected with the event or the owner (or the Authority) but am trying to make sense of the physics of such an event and what a 2' drop would look like in terms of the angle. Of course, there is the heel effect to consider due to the boat snagging on one side.
Grateful for any help!
- boat length 60'
- boat displacement 15 tons (steel construction)
- The snag occurred on the port side, 10' from the bow
- Narrowboats tend to sit lower at the stern than at the bow so the CoG is probably aft of the centrepoint (Assumption - is this true?)
The boater stated that the water level dropped "a few inches" then later stated that the sinking actually occurred when the level had dropped by 2'. A few maths wizards have suggested that a 2' drop at the stern would equate to 2 degrees of pitch which seems a very small amount to me, and I'm pretty sure my boat (about the same size) rose by a couple of degrees at the bow just by having an empty water tank... I also think that my boat going up the slipway took on more than a 2 degree pitch
I'm not trying to make the boater look bad, and am in no way connected with the event or the owner (or the Authority) but am trying to make sense of the physics of such an event and what a 2' drop would look like in terms of the angle. Of course, there is the heel effect to consider due to the boat snagging on one side.
Grateful for any help!
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