I only recently purchased a 4.8m fibreglass runabout with 80hpmerc, with a skid and centre roller trailer .... i have found it is easier to drive boat on as in video ... but i ensure trailer glides are just submerged. As a rule of thumb i only drive on the trailer if i was able to drive off easily. I normally only launch from ramp 3 at Patterson river Carrum vic ... perfect depth for my setup ..nice pontoon, moorings .... ramp 4 is too shallow and ramps 1&2 are cross tide entries.
To make things easier i will replace current straight centre rollers with self centring rollers and check out the latch system at Melb boat show early june
As a new chum to boating i have spent a lot of time observing others launching and retrieving boats of all sizes ....and have seen quite a few .mis launches ......one of note was a guy in a flash dual cab ute.. with a new jetski ...he got his jetski close to the water undid ties..his girlfriend offered to reverse his ute so he could launch jet ski and she could park ute ..seemed like a good idea to me ....but our macho man says ...no way a womans driving my ute so he starts to reverse down ramp hits brakes and his new jetski is dumped onto the concrete ramp ....macho man ...had taken off safety chain before he got in the water ... he brokes into a colorful display of language and arm waving before dropping to his knees and trying to get his baby in the water. deeply scarred his jetski floated but i'll bet she was back in the shop for repairs next day