Explain the meaning of the underlined phrases in your own words. Check in the Word List. before I got to the shore, guessing that it was about eight o'clock in the evening.

We therefore trusted ourselves to the mercy of the waves: We allowed the waves to take us wherever they wanted (Мы позволили волнам нести нас куда им угодно)
I swam as fortune directed me: I swam in the direction of the waves (Я плыл по направлению волн)
I was in the utmost astonishment: I was very surprised (Я был очень удивлен)
Ran back in fright: moved away because of (their) fear (Двинуться назад из-за страха)
Ventured so far: brave enough to get (Достаточно храбрый, чтобы получить)
By way of admiration: in amazement (В удивлении)
At length: after a while, eventually (Спустя какое-то время, в конце концов)
The methods they had taken to bind me: the ways they had used to tie me (Способы, которые они использовали, чтобы связать меня)