The Rules need not apply?

So what applies- road rules or maritime rules? And will the AA attend if they breakdown in the middle of Cook Strait?

From Stuff.co.nz

Men set out to drive van across Cook Strait
By BLAIR ENSOR on a support boat - The Marlborough Express
Last updated 10:23 06/09/2009

DEREK FLYNN/Marlborough Express
VAN-CY A TRIP: The two men left Waikawa marina under the shroud of darkness at 6am, heading out toward the northern entrance of the Marlborouh Sounds.

LATEST: Two men's attempt to cross Cook Strait in a van has gotten underway this morning.

Aeronautic machinists Adam Turnbull and Dan Melling made the news late last month after converting their Toyota Tarago van - called "Roofliss" - into an amphibian vessel.

The two left Waikawa marina under the shroud of darkness at 6am, heading out toward the northern entrance of the Marlborouh Sounds.
They have now entered Cook Strait, and are perched on the van's roof with a map.

Conditions remain good with the sun shining, very little wind and a gentle roll lifting the van.

The men aim to be at Mana Bay marina by 3pm this afternoon.
Responding to earlier doubters about the viability of their attempt, Dan Melling said, "Not many people would have taken a van across the Strait, so until you do you don't know, do you?"