History & Modifications
All boats:
All the class were decommissioned soon after entering service. They were placed in mothballs at
Barrow, but in 1998 were leased to Canada for 8 years with an option to purchase.
Unicorn:
Unicorn was decommissioned in 1995.
Unseen:
Unseen was decommissioned in 1994.
Upholder:
Upholder was decommissioned in 1994.
Ursula:
Ursula was decommissioned in 1994.