Hope this helps you
The motor that typically comes on a 23.5 is a 5hp long shaft. Mine came equiped with a 5 hp Tohatsu. If I had to do it all over again I would have chosen an 8 hp long shaft motor (probably a 4 stroke) with a charging system and remote throttle and electric start. No where in the owners manual does it state the recommended size of engine. This might sound kind of crazy but I have seen a lot of good used smaller engines on eBay for sale at some really good prices.Not sure where to acquire a mast crutch you might try calling hunter and see if a 240 mast crutch would work with a 23.5. The crutch that comes with the 240 is much nicer than the one provided standard with a 23.5.Grounding the hull to the trailer is typicall done using a rope tied from the bow eye to the trailer. I do like the recomendation of the chain maybe with an eye on each end. Then there is a strap across the back connected to both sides of rear of the trailer.