: ...who once said that there was no need to use the 500 over the 400?

Sounds like me, doesn't it?

I still say there is no 'need' as far as pumping capacity is concerned, as the difference isn't that big a deal for me.

It has more to do with the availability. When I walk into a boat supplier these days, I'm much more likely to find a 500 on the shelf these days than a 400. Who knows why? Placing a special order with West Marine adds at least $5 to $10 to the price, so I'm just taking the easy and cheaper way.

Also, having found an easy way to adapt the large 500 outlet down to a reasonable 1" diameter outlet was a factor.

By the way, Hawaii's Kauai is still as beautiful as ever. Too late in the year for anyone to rent me a kayak for ocean paddling, though, as it's getting on into what passes for 'winter' down there.

Pete,
in Snohomish, WA