The 35ft vessel - with what appeared to be the name Misty on its bows - disappeared while it was moored on the River Ouse, near King's Lynn, on around May 12.

So far the King's Lynn Conservancy Board (KLCB), which controls navigation on the lower reaches of the tidal river, has been unable to find it or trace its owner.

A picture of the cruiser partially-submerged before it sank near the ruined church at St Germans which was shared on social media (Image: Facebook)

The board has issued a warning to boaters to proceed with caution in the area it was last seen partially-submerged near the bridge at St Germans.

But boat owners who use the river to access the Wash and nearby ports such Wells and Boston from their berths inland say the missing wreck has left them unable to get to sea because of the risk of hitting the underwater hazard, which could be anywhere.

BOATERS' BROADSIDE

Gary Evans and his wife Morag were hoping to set sail from St Ives in Cambridgeshire on board their cruiser with a flotilla of other boats next month to coincide with Mrs Kemp's 60th birthday.

Gary and Morag Evans aboard their sea-going cruiser (Image: Gary Evans) They were due to stop off in King's Lynn and moor up at the quayside for a special party booked at Marriott's Warehouse.

"Due to what we feel is the river authorities' incompetence, we may need to cancel this........

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