3 DC 15 checks (actually it says "A series of checks" and I figured 3 would be enough). However climbing IMO would have been more dangerous because the nearest low tide is during noon-3pm which is the hottest part of the day. Also requiring fortitude saves vs hot weather or facing heat exhaustion. Failed checks of more then 5 put you into the sea, letting you cool down but potentially giving you a rougher time<br/><br/>With Baroks rope I think its fair to say even if you fail you can still pull yourself aboard. Unless you get a critical miss