Possible Clues:

• Able to be comprehended
• Able to be got?
• Easy enough to grasp, like umbrella during shower?
• Inferior base given to sailor by the French is to be expected
• Making sense, like an umbrella when it's raining?
• Powerless to take over the German base, it's clear
• Lacking capacity to accept the German attitude? That's to be expected
• Realise expert can be taken in
• Can be appreciated that it is reasonable