I guess you could, if your neighbors are not grossed out by it. I also don't know if the typical shore side toilet can handle all that waste at once and what the owner of the shore side head
might think. The smell might be horrendous for anyone who walks into the restroom at the same time. Plus it seems like a huge unnecessary hassle to have to do this. Is there a portable MSD pump out boat in your area?
are required to have a pump out facility and it is supposed to be free as well.