A question about Boscastle Blowhole (S entrance at SX 09370 91537 : I have looked at some Youtube videos of the 'Blowhole'. eg https://www.youtube.com/watch?v=v22NZ90tMjY
This appears to mostly operate as the blow- back type in which an incoming swell seals the rather low entrance and compresses air inside the (usually dead end) tunnel. When the swell recedes a bit, the air comes back out taking spray with it more or less horizontally.
And then I looked at some dive videos which make it clear that this is a through tunnel, more or less NS, right through the headland and, from gridreferencefinder.com , 63 m long.
Another blowhole video states that at low tide, waves from the N end produce spurts at the S end.
Both mechanisms may credibly apply at times, depending on tide and swell direction.
Has anyone any info on the ceiling profile along this tunnel ?
The diving videos, unsurprisingly, give no info on this.
This appears to mostly operate as the blow- back type in which an incoming swell seals the rather low entrance and compresses air inside the (usually dead end) tunnel. When the swell recedes a bit, the air comes back out taking spray with it more or less horizontally.
And then I looked at some dive videos which make it clear that this is a through tunnel, more or less NS, right through the headland and, from gridreferencefinder.com , 63 m long.
Another blowhole video states that at low tide, waves from the N end produce spurts at the S end.
Both mechanisms may credibly apply at times, depending on tide and swell direction.
Has anyone any info on the ceiling profile along this tunnel ?
The diving videos, unsurprisingly, give no info on this.