Bizarre and scary weather phenomena at sea

In ‘The Kerracher Man’ Eric Macleod relates his time with his family crofting on the shore of Loch Cairnbawn, near Kylesku. One episode describes a frightening experience in an eddy of wind generated by Quinag, a mountain some 750-800 metres high, perhaps 4000 metres from the loch. Whilst out on the loch in his 20ft Taskforce (trihedral hull, 2 x40hp outboards), Macleod describes ‘a spectacular but innocuous spray of water dancing up from the surface of the loch’ in just ‘a hint of a Westerly’ (Quinag lies to the South of the loch). The spray of water approaches him and envelops him in ‘wall of water twice my height’ and the boat was spun around and driven down in the water so far that water began to pour in over the stern, and would have sunk the boat if it had lasted more than a few seconds.
This sounds an extraordinary and terrifying experience, appearing out of rather benign looking conditions.

Bearing in mind the climate of northern Scotland , and that it is unlikely that there is any significant thermal activity going on here, can anyone offer any amplification, ideas, possible explanation, or any other experience of extraordinary, odd, weather or sea phenomenon, as opposed to ferocious storm conditions?

 

Bubbles, rising under the boat, so there's no bouyancy. This is one Bermuda Triangle theory, where ships have disappeared without a trace in good weather. It theorized that the source of the bubbles is seismic.

 

I witnessed once a twister on a clear calm day on lake.. it lifted a visible water pylon some meters high.

 

something possibly similar happened in the 70's or 80's and caused great havoc with the lunchtime crowd who used to get 30 minutes sailing beach cats in front of the city... Sailing cats cartwheeling all over the place and injuries galore on a relatively balmy day...

 

Sounds like a condition of this:

http://en.wikipedia.org/wiki/Katabatic_wind

Everyone that sails San Francisco Bay has heard about the South Tower Demon that stalks the unwary when offshore is cloudy and the valley sucks...And up here in Pacific Northwest are the "williwaw" winds which can be 80+ knots down the narrow channels. Geographic features that bend and channel the wind in specific weather conditions abound.