With regards to the terms …

With regards to the terms "houseboat" or "other floating structure":
Just what is meant by the term "floating structure"? If this term is in reference to what are normally referred to as cruising boats, as in sailboats and powerboats that are equipped with a galley, head and sleeping quarters, you have managed to effectively remove the reason for owning such a vessel from tens of thousands of Ontarians and out of province tourists.
Many of us own and use these vessels for the express purpose of anchoring out - I will NOT use your derogatory and insulting term "camping on the water", that is not what we do - and enjoying the towns, cities and remote wilderness areas of our province.
There is a reference within the proposal claiming that marinas would benefit from this change. That is not the case at all, for three reasons.
One, a great many of us would simply sell our boats, there being no way to enjoy them under the proposed rules and two, there is not enough marina space vacant to accommodate all the vessels moving about and most importantly, most of us do not wish to spend our weekends at a marina.
Go look at any marina in the Georgian Bay or North Channel on any weekend. They're empty, because the owners are out enjoying the beautiful waters, islands and shorelines of these bodies of water. And to point two, does this mean there is space for those who do want to go to a marina? No, because the boaters return Sunday night to their marinas to reclaim their docks for the week.
Frankly, whoever thought up that idea is clearly not a boater, and/or has no exposure to the realities of boating in Ontario.

With regards to the proposal that there be a 300 metre setoff from developed structures, shorelines or docks:
There are a great many reasons that this proposal is deficient.
First of all, the proposal effectively takes control and de facto ownership of the submerged lands from the public at large (including the boating public) and gives it to the owners of said structures, shorelines or docks. Docks of course means cottagers, so these landowners will now have an increased area of land to their sole enjoyment to the detriment of boaters who would otherwise be free to use these submerged lands.
I can assure you, there are many boating groups that would very swiftly take the province to court for such a regulation. I and thousands of other boaters would gladly help finance such a court action.
Secondly, a great many of the anchorages used by boaters would effectively be put off limits by such a proposal. This has several ramifications.
As referenced above, the proposal will remove the reason for owning a cruising boat for a great many people who enjoy anchoring out. This will have a significant negative effect on the boating industry at all levels, as well as boating industry infrastructure, and on boating tourism. Each of these generates significant economic activity and income in Ontario.
Secondly, in times of inclement weather, boaters choose to anchor in sheltered bays and coves for safety reasons - precisely the locations in which a great many cottages with docks, boat ramps, etc., are to be found. So there is a distinct safety element in play here, and this 300 m rule puts boaters at risk of being unable to wait out bad weather in a secure harbour.
Note: I am aware of the legal meaning of the term "safe harbour", which is my reason for using the term "secure" harbour above.
Your proposal appears to make it illegal to anchor at any time within 300 metres of docks, etc. Such a proposal would find great opposition from fishermen, a very large population of boaters in Ontario, again with the above noted negative effects.

In conclusion, your proposals have no benefits that I can see, to include any supposed protection of the "environmental integrity of each camp site".
Further, your proposals are the antithesis of "fairness" in that they remove rights from a significant portion of Ontarians who would typically use these submerged lands.
Lastly, they completely and illegally strip access to these lands from that group.
These proposals in fact appear to be a response to owners of waterfront properties who object to vessels at anchor within their view. Since these landowners do not own the land over which these vessels are anchored, this would be a de facto illegal taking of the public's right of access to these lands. These landowners have rights to their property lines, and not beyond them by a single centimetre.
This proposal is eminently and imminently actionable in a court of law, and I predict that if it is enacted as I've seen discussed, the ERO will very rapidly find itself in court to defend its meritless proposal.

I work as a professional in the boating industry, have extensive boating experience in the Georgian Bay and North Channel areas, and am actively involved in boaters' rights issues. I am also a writer for several major boating publications, and a regular speaker and presenter at the Toronto Boat Show, as well as other boating forums.
I trust that the ERO will see the error in creating a 300 metre setoff and discard this idea. If not, rest assured, the ERO will find itself in court quite rapidly as boaters and their various organizations react to these proposals.
Note - this letter has been copied to those MPPs whose constituencies would be affected by these proposals.