Re: Shrinkwrap, tarp or, custom cover?
Since I do shrinkwrap as a side job, I am going to suggest shrinkwrap.
Now for the why.
Unless I was going to go with a fisher cover, I would not consider a tarp. Getting a tarp to fit right with no sagging or pooling on a large boat is next to impossible. Also a tarp will flap and scratch your boat.
I wish I could find the picture I took last year, of a large sport fisher that had used a tarp. the entire cockpit looked like a skating rink. It had snowed, I can only assume that the tarp collapsed, the snow melted then froze again. It looked bad.
A properly installed shrinkwrap job, will have the boat looking just like the day it was wrapped. You can have a door installed so you can work onthe baot all winter long.
As far as reusing the shrinkwrap from year to year. I will not reinstall shrinkwrap. There are three parts to shrink wrapping. The first is to install the frame work using 3/4" woven strapping and 2x4's. This frame work has to be very tight, including the strap around the perimiter of the boat. The second is placing the shrinkwrap material over the frame. The third is shrinking the material. This makes a tight snug cover.
Reusing an old shrinkwrap cover makes steps 1 and 3 tough to do. If you do not get the supports in the same spot, the cover will not fit right. it is also very hard to get the perimiter band tight a second time. Third you can not reshrink the material. If a customer wants to do this, I will not help them. Not to say it con not be done, but I do not want the responsibility of it.
As far as mold and mildew in the boat. I would never wrap a wet boat. It does not matter tarp, shrinkwrap or canvas, a wet boat is an invitation for mold. Also the cover needs to be properly vented. If that is done, there is no reason a boat should get mold over the winter.