Ah, but when you install the scoop strainer, which direction does it point? So water is pushed in by the forward motion of the vessel, or with the streamlined section forward? I install them "backwards" on sailboats and "forwards" on power boats (like the Dyer 29 I'm finishing off). "Backwards" because I don't want a water column pushed into my engine sailing hard - and I don't have to be concerned about closing the raw water thru hull to avoid that. "Forwards" on the Dyer with the Cummins to "scoop" water and push it into the system. Unfortunately, we're loaded with sargassum weed here at 18N, and sure, you can close your valve and clean out your inboard sea strainer (daily) if you don't have a hull strainer. But I came to the conclusion to keep the hull strainer (properly oriented). I think it may depend on your cruising grounds to an extent and the type of flotsam you're dealing with. Barnacles are another thing altogether, and I've seen the perforated strainers absolutely stuffed with them. At least the grooved strainers you can get a screwdriver up in there.