Both sides scored one try in a hard fought game, but it was the home full back James Bird who converted all five of his attempts with Stu missing with three of his own efforts.
The West skipper's day was to get worse with that serious shoulder injury in the second half.
We almost got off to the worst possible start when Zac Southern failed to hold a high kick and Alnwick skipper Frank Hutchinson kicked on with the ball coming to rest just behind the West try line.
Fortunately Waites won the foot race to earn a 22 drop out.
Alnwick went ahead from Bird's first penalty on ten minutes. Three minutes later we replied with a debut league try for 17 year old winger Joe Willis.
Peter Youll, who made ground most of afternoon, had broken through the midfield to set up an attack which saw Southern enter the line.
The full back sidestepped two defenders to send Willis in at the corner with the youngster having the presence of mind to set up an easy conversion for Waites by heading for the posts.
In a tight first half Bird reduced the arrears with a penalty before the home side scored a fine try on the half hour.
They'd lost scrum half Todd to injury with winger Rob Cuthbert taking over to fine effect. He finished off a move started when Bird surged through the middle opening up a gap for Cuthbert to finish in style under the posts.
We began the second half trailing by only six points and spent the first 15 minutes in the Alnwick half.
The forwards camped on the home line with surges for the line from Andrew Rollins, Owen Bennett and Chris Atkins which were all repelled.
The pressure did produce penalties with Waites just wide with a long range effort from 40 metres and a similar result from a kick from just outside the 22.
Inevitably for the visitors when Alnwick did force their way back into the West half they were awarded a penalty from 35 metres which Bird slotted. That was followed by another from just outside the 22.
Alwnick looked dangerous whenever they attacked. However, both defences remained on top with Gavin Painter taking over kicking duties form the injured Waites as we looked to close the gap.
With Aaron Myers constantly running at the home defence the West fly half was given two close range opportunities. The first came after Myers took a tap and go and was hauled down just five metres from the line.
With the clock ticking down he went on to secure the bonus point after Myers again forced a penalty from the home forwards.
Injuries and World Cup absences will provide opportunities for some for next weeks' visit of unbeaten Doncaster Phoenix.
Alnwick: James Bird, Peter Moralee, Rory Mallaburn, Frank Hutchinson, Rob Cuthbert, Callum Burn, High Todd, Peter Brown, Hamish Burn, Richard Elliott, Josh Burgess, Oli Sutherland, Gordon Smith, Ben Gothorpe, Ritchie Ellis.
Reps all used: Matt Grey, Danny Clayton, Andrew Shell.
Tries: Cuthbert.
Cons: Bird (1).
Pens: Bird (4)
West: Zac Southern, Joe Willis, Stu Waites (capt), Peter Youll, Scott Butcher, Gavin Painter, Ryan Painter, Michael Hogan, Andrew Rollins, Ross Wood, Owen Bennett, Chris Atkins, Liam Bailey, Aaron Myers, Sam Miller.
Reps All Used:: Jack Angus, Luke Mallinson, Dan Boatman.
Tries: Willis.
Cons: Waites (1)
Pens: G Painter (2)