Is it worth diving the Madeira? Or are there better wrecks in Superior for divers like us with not a lot of experience?
The Madeira is one of the few wrecks anywhere that is readily accessible from shore; the Hesper, just up the road a piece in Silver Bay, is another. I think they are fun dives -- the water is clear and cold, and the wrecks are well preserved for their age. There is little if any aquatic life, so the attraction is the wrecks themselves.
While it is possible to visit both these and the many other shipwrecks in Lake Superior via boat, it is difficult to arrange. There are no established dive boats that serve this area on a scheduled basis as there are in typical tropical destinations. There are liveaboards that visit Isle Royal, and it is possible to schedule charters in advance if you are willing to organize something with your friends and pay to charter the entire boat for a day. Either of these are costly alternatives and require you to have a sizeable group of diving friends with compatible interests and skills. It is also possible to use your own boat (a step I am now taking) but Lake Superior places considerable demands on the skipper and vessel; there's a reason there are hundreds of wrecks to see.
Therefore, the attraction of these dives is that they are a unique opportunity for a local wreck dive from shore.
And what caused the fatality at the Madeira?
There is a thread in A&I that includes an eyewitness narrative.
The decedent was an inexperienced, young diver who was there as part of a group. He was new to drysuit diving and was taking the dive as part of his drysuit speciality class. There were so many things that went wrong that it is difficult to identify a primary cause. The main lesson that I would take away from it is that he was not comfortable enough with diving in general and his drysuit in particular to deal with the considerable demands of the site.
People dive the site in different ways. My approach is to dive it with a twinset, from shore, and swim out to the wreck underwater. Other people swim out on the surface and make a relatively short dive with just an AL80. Others use a boat.