Translation of Implikation

I need to write you one more sentence. This is what my teacher told me and the German language is so difficult. So please, as a last favor, would you please write the sentence for me in German?
I am happy that you are satisfied with your results! Of course I will come again. However, next time I would like to speak to each of the professors in advance to see what their need is.
We had to be careful of not falling into the water. We rowed for about an hour and we got tired pretty easily. Especially the other man and woman looked devastated, at the limit of their physical capabilities.