Hi Grags and welcome to the site. Your question about the boat incident is easily explained.
The Bible includes some of the variable writings found in many contemporary handwritten documents which were circulating in the early centuries of our calendar. Many of them refer to a particular but fictitious event. These documents were in the nature of stories to teach a moral tale or illustrate the miraculous power of the hero in question. Remember that Dionysus (who was crucified and turned water into wine) and Mithra (the Great Shepherd) were also "christs" with each cult lauding their own 'saviour'.
The earliest Christian writings did not contain the name Jesus such as in the Shepherd of Hermas which was the most popular Christian text for two centuries but never got put into the Bible canon (the approved books). The Bible books were only later selected by the Roman Church mainly around the early fourth century but the canon was not determined for at least another century and even today it is not universal.
Do ask your study conductor what happens to a JW who has got baptised and then changes his mind about his choice of religion.
Out of genuine regard for your peace of mind, please believe me when I say that membership to Jehovah's Witnesses in about 50% of cases brings about appalling family rifts and turmoil. Unfortunately I know from personal experience.