Thanks for your comment - I appreciate it. Yes, there are specialized bulkers for the great lakes. Mostly carrying iron ore, or now taconite a processed ore, from the upper lakes to the lower lakes and coal from the lower lakes all over. At one time there were hundreds and hundreds of lakers. Today there are just a few dozen. Each year one or two gets retired and often is replaced or is cut down by a tug barge combo as they can operate with a much smaller crew.
On this site there are numerous photos of lakers. The site administrators just put them in a separate sub category so if you click on the bulk cargo category you will see a variety of categories including Great Lakes bulker and if you click on that you will get a good representation of the lakers both current and some older ones. Most lakers now have self unloading booms and conveyors; a handful are still "straightdeckers" without self unloading equiipment. There is an excellent web site dedicated to Great Lakes shipping called "www.boatnerd.com" which has latest news posted daily, photos posted daily (except this weekend for some reason) and a photo gallery, message board and a variety of other features. There is also a few sites dealing with the Welland Canal a 7 lock canal over the Niagara Escarpment that connects Lake Erie and Lake Ontario.
The lakers can be found all the way down the St Lawrence Seaway to the St Lawrence River to places like Montreal and Quebec City and a few lakers are designed to be ocean going ships -- most have fairly flat bottoms and are not designed to sail on the open seas.
There are a handful of lakers that are 1,000 feet long and were built on the upper lakes and are so large they cannot go through the Welland Canal so are found from Lake Erie on up. They were designed for iron ore hauling but also haul coal, especially since Montana and Wyoming coal that is low in sulfur content has been transported down lakes from Duluth, Minnesota since the Clean Air Act was passed in 1970.
It has always amazed me that Duluth, Minnesota is one of the more active ports -- it is very close to the geographic center of North America, about 1,500 or more miles from the open ocean.
Hope this info is helpful. There are about a dozen of us who post photos of the Great Lakes and the St. Lawrence. The most prolific are Canadians along the St Lawrence like March Piche who posts under the name Photoships. He just posted his 6,000 photo and all of them are excellent, both salt water and lakers.
Also, the St Lawrence Seaway, Welland Canal and Sault Ste Marie (Soo) Locks close normally by January for the winter so it is not a year round activity and we are really climbing the walls when the lakes open again in the spring.
I have not posted much in the way of lakers recently as I have seen much of them and dedicate my very limited time on the water to photographing salt water vessels I have not seen before.
If you have any other questions let me know.