It sounds to me like the Lavacs where not carefully installed in the charter boats. What a surprise! Another thing about a Lavac is that since it works differently than other marine heads, a small amount of user training is required. I would not put one on a charter boat for that reason.

However, once properly installed, you will not have wet seats or lids; and it will still be going strong long after you have done 10 rebuilds on the Raritan and then thrown it out.