Learn Arabic (Modern Standard): ستستمر الغواصة في الغوص، وإن كان الماء باردا جدا. - The submarine will continue diving, even if the water is very cold.

Yes, literally it means 'and if.' However, in Arabic, adding the conjunction و (and) before the conditional إن (if) creates a concessive conditional meaning 'even if.' You will also see حتى لو used for the exact same meaning.

The main clause is in the future tense (ستستمر - will continue). Why is the verb after وإن in the past tense (كان - was)?

In Arabic conditional sentences, the verb immediately following the 'if' particle (إن or لو) is generally in the past tense, even when talking about the present or future. Since the main clause is future (ستستمر), we translate كان as 'is' (even if the water is cold) rather than 'was.'

Why does باردا (cold) have an extra alif at the end?

It is in the accusative case (mansub) because it is the predicate of كان (the descriptive information about the water). The subject of كان is الماء, which takes the nominative case, so its predicate must be accusative, written here with the fatha tanween on the alif: بارداً.

Are the words for 'submarine' (الغواصة) and 'diving' (الغوص) related?

Yes! They both come from the root غ و ص, which relates to plunging or submerging. الغوص is the verbal noun (masdar), meaning the act of diving. غواصة uses a common structural pattern (fa'aala) frequently used to name machines and tools, making it literally 'a diving machine.'