Border Patrol boat that patrols western Lake Erie. They're not sayin'.
Four 300 Mercs.
Note gun mounts fore and aft!

My educated guess - mid-60's.

But the bullets are going a hell of a lot faster.

that boat was up here for a few years on lake ontario they had little sassquatch decals on the windows their moto was" you might see us but you don,t know who we are" ....their mission was looking for drug running subs and would run all night using a 1000 in fuel each night they would show up and act like navy seals and had a huge attitude issue they pretty much did not get along with anyone it was a branch of customs. the boat is not fast and broke often but the 20,000 grand seats were cool

Yeah, they're big bullets too! I would have thought faster than mid 60s.

FL coast guard uses similar boats but only seen triples not any quad boats. I would guess mid-upper 60's is the limit on those.

They are made to be stable not fast.

Back in my Jet Ski days we were sitting in the locks with a Coast guard boat like that and they asked us to race them. I thought it was some kind of trick to bust us but the locks opened and it was game on.
None of our skis were stock of course and on a calm river they had no chance.
Since then I can always say I outran the Coast Guard

I know for fact 60+ not sure on top end. Ran into one of those all blacked out up on the St. Lawrence one day when I was the only boat on the river....came up a LOT quicker than I expected.

Came up and ran next to a triple Honda engined one in Galveston Bay. He seemed to be maxed out around 60.

OK, not as fast as I thought. I figured at least 75. I'm gonna defend these guys. I see them a lot and they have never bothered me. On this day we were taking a beer break at the Detroit River Light on our way to PIB. We went over to them to talk to them. They asked if I wanted to trade boats. I said sure, as long as they include the weapons.They asked how fast I was. I said mid 80s. They said I could outrun them then. I'm like, yeah, right, until the choppers show up. Saw them again at PIB that day and went over to say Hi. They are good people. At least they have been to me.