Sun protection is vital and I have seen many paddlers get in strife, because they failed to have a proper plan. My plan is as follows:
If you look at the picture of me below you can see my red sunshade which is made out of Ripstop nylon which you can buy at Spotlight. It is easy to make. Place some shock cord around the coaming to keep the fabric taught and mark the outer edge of the coaming with a pencil. The length of the fabric should be approximately from the front of the coaming to 15 cm from the back. Sew in a hem and thread the shock cord in. Tie a knot in it so it fits firmly inside the coaming.
When it is pushed forward it takes up very little space. When you are in the boat pull the fabric back towards you until it reaches your waist . The great thing about this item is that it keeps the sun out, most of the spray just evaporates in the heat and as it is reasonably loose at the waist it ventilates. Conventional spray decks can be very hot and clammy.
[There is a Ready-made alternative - Sea To Summit Solution Gear Sun Deck - ECK]
I recommend the legionnaire type of hat that I am wearing in the photograph. This provides by far the best protection for you face and the back of your neck. A very popular and good hat is the Adapt-a-Cap which is also of the same design and you can get very bright fluoro colours which are excellent for visibility. Nearly every experienced paddler in the event wears this style of hat.
Use a good SPF 30+ sunscreen on your face and also on the back of your hands if you are not wearing gloves (Get your land crew to do this as you do not want to have a greasy hand on the paddle —- it can play havoc with your wrist)
I strongly suggest using zinc cream on your lower lip as you can get some spectacular burns there. Either carry some in the boat or pace a blob of it on your foredeck, so you can re apply it several times during the day.
A pair of polarised sunglasses is essential.
[Make sure you do not loseyour sunglasses when you are on the water - secure them with Hides H2O Floating Sunglass Strap - ECK]