Nice one!
And towing it with another boat might be a safe option. All the speculation has been about single boats but now we know they had barges the possibilities are expanded.

Quote
There's one very interest theory been put forward lately: get your great big rock in a tidal area and strap the biggest boat you have to the top of it. When the tide comes in the boat will lift the stone, which will weigh half as much under water as it would in the boat. You can move a lot more this way than if you loaded the boat with stone.[/quote]

Hi Four Winds

Another good idea in theory but in practise there is a major problem, with the stone outside and underneath the boat we have the problem of water resistance againts the stone, this could well reduce the speed of the craft through the water from perhaps 6 knots to 1 or 2 knots. With tidal currents in places on the Welsh coast running at perhaps 3 or 4 knots you can imagine the outcome.