Nitebell & Roemer
Gentlemen; this is a forum to seek help and offer well intended advice.
If the mfgs specifications were not followed, it really does not matter how the damage occurred, ultimately it is the boat mfg's job to roll the cost of this back up to the subcontractor who goofed up.
Yes the grit that did the damage may very well have gone thru a strainer, but absent the strainer, if it was required by the mfgs. specs. it is irrelevant to the repairs now. going forward this damage may very well repeat itself even with the addition of the strainer, but for now the relevant issue is to get Regal involved in the solution give them the opportunity to fix this in current production and at the very least provide the strainers and water pump at no cost to NiteBell.
Nitebell, if it is any consolation, i had to replace both raw water pumps on my boat at about 2 1/2 years and 200 hours. the list price on each was $1,200.00. two things i have learned to prevent this repeating on my engine; use the boat more frequently and change the impellers annually. (My boat sat quite a bit before i bought it) no problems like that since.
if you have not done so already, i suggest writting a kind letter to regal and cc your dealer and explain in detail with supporting documentation how regal and its subcontractor failed to follow the manufacturers specifications on installing a sea strainer and request a specific course of reasonable action from them that you feel would make you a continued satisfied regal customer. I would be surprised if they don't do anything if the specifications are current and have not been changed by Yanmar.
look forward to hearing how you fare.