So I called my insurance company (Markel) last night. I was asking the representative questions as best I could about coverage for these different scenarios. Not to anyone's surprise, but a lot of her answers were the standard (it is up to the adjuster after an incident occurs). However here is what I could ascertain.
At least with my policy (and please forgive me if I am using the wrong terminology) There are 2-3 categories they put claims under. 1 or 2 of them are covered under damage less than hull value and "full total" (hull coverage) i.e. lightning strike, collision, sinking, fire, etc....
The other category is towing/assistance services coverage. My policy had a coverage of up to $750 for towing/assistance, I asked how much I could up the coverage to and their limit for my boat was $5,000 towing/assistance coverage for an extra $83 per year. I had them add the extra coverage so 5k is my new limit. Figure for 80 bucks I will feel more comfortable about getting assistance from a non-contracted provider.
I also asked about if they worked with any company in particular and they explicitly stated they do not endorse or work with anyone, hence forth the towing coverage part of the policy. If I were to need assistance from someone just contact them and submit the bill/report after everything is done.