Three boats and a campervan were set alight in Picton overnight, keeping firefighters busy.
The boats and the caravan were all at separate addresses in the same area of Picton.
They appeared to have been deliberately set on fire about 3am.
Two of the boats were extensively damaged and one had suffered moderate damage.
One of the fires had scorched the side of a house and caused windows to break.
Picton chief fire officer Wayne Wytenburg said he had to call Blenheim staff in to assist them with the callouts.
He could not comment on whether the fires were related.
Police would like to speak to anyone who was in the Waikawa Rd area about 3am today.
- The Marlborough Express