Did Oostende last year on a 35ft, first time ever at sea other than the ferry, did it again this year but on a 40ft, both times with highly experienced skippers. First time it was flat calm until we were within sight of Oostende, then it kicked up a bit and I was bouncing around the foredeck trying to sort out fenders while three heavies came out of the harbour. Rough, but nowhere near as rough as it got on the second crossing. Return journey first time, weather forced the decision to head for Ramsgate instead of the Crouch.
Second time, this year, set off at night into a lumpy sea but this soon settled down and we ended up motoring most of the way. Return trip was brought forward a day the same as MoodySabre, we left and headed out into a calm sea, crossed the main TSS before the weather changed and we had a F7 touching F8, which stayed with us until we were in the shelter of Landguard. Thankfully this time there wasn't much rain, just plenty of spray.
Doing it again next year on my old 21ft Debutante, in company with CentaurPipedream. Plan is to allow plenty of time either side of departure and return so we don't have to head out into rough weather. If it turns we'll live with it, but I see no point in putting myself or wife through rough stuff when there are other options, vital thing to consider on a small boat with almost novice skipper and crew.
Have plenty of dry clothes to change into when you get wet, if you don't get wet it's a bonus.
Both take regular breaks even if it just means a rest below, or even putting your feet up and closing your eyes for a while to relax.
No alcohol during the trip, and avoid excess the night before, especially for the return, you'll need to be switched on for the TSS crossings which start almost as soon as you leave Oostende.
Prepare plenty of hot drinks before you set off, making a hot brew even on a larger boat when the weather kicks up can be interesting, and not something I want to be doing on a small boat.
Food and nibbles will be readily available on Sixpence. When it gets boring the extra boost you get from carbohydrates helps keep your mind focussed
This was taken on the last return trip from the cockpit of a 40ft, looking up
Crossing a TSS is nothing like as scary as some try to make out though, but stay switched on and keep your eyes open. Allow plenty of time and make sure your boat is kitted out, and you, and crew, are rested and prepared for the crossing. Then do it and enjoy every minute of it, if lucky, you'll even see the dolphins, they came to play with us the first time.
Be prepared for the worst, but avoid going out into it if you don't have to.
Hope that helps ?