Can anyone tell me the dimensions of the large when closed? I need to see if it will fit in my anchor box.

I have a large in my shop and will measure it.

Which type is better for a mud bottom: box or fortress? Thanks.

IMHO th Box. I have the small that I use on my 30 cat, and its never failed to set on first throw and always holds. usually comes up covered in mud when I pull it in.

I would also agree, go with the large. There isn't a whole lot of difference in weight between the two. So far our large has been great with a 36 Outlaw.

I have the large for my Top Gun. Holds many boats rafted up with me. Great holding power. fits in the supplied bag in my back seat.