cost hopping clockwise from Humber estuary to Solent?

[Robin]

Grimsby has an easily accessible refuelling berth. Wells it tricky for refuelling in that it needs to be done at high tide.
15 knots is uneconomical in a planing motorboat.

I meant more for planning purposes than actual as it might be some at 8kts, some at spells at 20kts. As a lifetime rag and sticker, 8kts average is fast, but point taken! We cruised a SD trawler here economically in the ICW at 7.5/8kts at15kts the tanker would have to keep up behind!