Normal electrical insulation tape along the blade edge so it goes half half around the edge, pulled tight as you go.
Around blade, around shaft, around blade etc, about 5 -10x
Lasts ages, dirt cheap and easy.
Insulation tape good you could also try ion rail savers tape available from some windsurf or surf retail stores.
The tape is applied along the rails of the board not paddle blade.l think mark has answered that for you.
Nitto electrical tape. Can be stretched around the curved bits without loosing its structural integrity.
The specialist Sup shop I got my Sup from don't recommend rail tape and don't even sell it I was told, they recommend the electrical tape on the paddle there opinion is that the rails on a sup are strong enough to handle a knock from a paddle.
Always had rail tape in the past so I will see how it goes.
Anyone else reckon its not necessary to tape rails?