For a simple, seaside-inspired sweater, SWS makes a very nice beachy colourway, and it's stripes knit up in great thicknesses.
Inspiration:
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Top-down Raglan Cardigan
Paton's SWS (3 balls)
5.5mm
5st=1"
Photos incl:
CDGibson, Pookie at the Seaside, Granny, and Ferry Cake Sweater at Alderney Landing.