JimH wrote:

These marina's on the Great Lakes are not set up to handle sudden and large
fluctuations in the water level as we obviously do not have tides.

Yes you do. Just not enough to bother, or even hardly notice! I looked
it up because your statement made me think *why not*?!

http://www.great-lakes.net/teach/cha...100_tides.html

According to the Canadian Hydrologic/Hydrographic Service, the Great
Lakes experience tides from 1 to 4 cm, the strongest being on Lakes
Superior and Erie. These tides are often masked out by meteorologically
induced phenomena, such as a seiche (pronounced "sayshe"). When wind
pushes down on one part of a lake, the water surface rises in another
part, producing waves (most noticeable on Lake Erie because the lake is
so shallow).