"Basically, they're abandoned vessels. Usually people have left them on a borrowed mooring or at anchor and never gone back for them. We have to declare them a wreck and go through quite an involved process to sell them."
Mr Lyle said 'wreck' was a technical term that referred to a vessel being abandoned or found drifting and its potential to be a marine hazard, rather than its condition.
"Sometimes they're boats where the owners have rented a mooring and never returned. We've had a couple of times where someone has moved to Australia and just left their boat behind, or people have died and for some reason the boat is forgotten about."
Without a central registration scheme, he'd like to see all owners leave their contact details somewhere on their boat, Mr Lyle said.
"Quite often boats go adrift from their mooring and we don't know where they come from."
One of the yachts that will now be sold unless claimed and paid for is "Equaliser", a 7.8m Beale-made sloop that was illegally moored in Matauwhi Bay for some time. The other unnamed 7m yacht, of an unknown brand but similar to a Raven design, is sloop rigged, with a dark blue hull and cream topside, and was illegally moored at Windsor Landing in the Kerikeri Inlet.
If the owners fail to contact the Northland Regional Council and arrange to pay the debts by tomorrow, the vessels will be sold, Mr Lyle said.