Try a bar of soap (yes, bath tub soap) rubbed on the centerboard and the lips of the gasket
as well as the sides/flanks of the centerboard where the pivot point is.
Not sure which Starboard design your board has, so maybe have a look in the cassette
and see it the side shims are too tight.
Silicone attracts sand, sand increases the friction between the centerboard components.
Do not use silicones!
Sailkote works pretty good on masts and camber inducers, but it also attracts and holds
Soap is the absolute best lubricant for windsurfing equipment!
If all else fails, maybe find a way to thin out the lips of the gasket at the rear of the
For sure open them up and run a file along the sharp edge on the top side (up in the CB
The gasket will seal just as well, but a sharp edge on the upper longitudinal corner of the
gasket will for sure hang up on the center board when fully retracted.