How much rope do you have? The advantage to the boat anchor is that you might be able to wedge it in this brush or even the other entrance. Peut-etre?
Well I didn't think of using the boat anchor as an anchor.
I jus thave 10 meters of rope.
I might be able to wedge it in the grass, throw the rope above the block and climb from the other side.
Not sure if it would hold ...