We have done from Bracklesham to Brighton marina but not all in one trip.
As already stated watch out if you go in shore of the Mixon Hole at low tide, water there get less than 0.4 of a metre. The next thing to look out for is the all the divers in Pagham bay on the outer mulberry, this will be easy to spot because of all the dive boats tied up or just plodding around. The next thing is the Bognor rocks, these can break the surface at low tide approx 2 miles off shore. These are straight out from the pier but cover a large area. Apart from these, there will be loads of pot buoys and lines to try and negotiate.
If you need fuel on route it can be got at Littlehampton which would be about half way.