if you look into how to build a raft i posted an answer there

where do you find the rope?

To get across the lake (which is actually a volcano) you must build a raft on the beach
using logs and rope. Rope can be made from vines. Find the vines take them to the north
west basket of you cave. Than talk to Skye, request that she make you some rope. You will
need lots of rope and lots of logs. One vine will make one yard of rope. You can only
build the raft a little at a time. In fact, I think you need to have 12 logs and 12 yards
of rope. But I dont' really remember, its been a while since I made the raft :]

Hope this helps :]

If you need anymore info just contact me. Or you can look up
my answers on other questions :]

stop going:]ok!