I had one in my old cuddy and the threaded portion is no where near the pump.......mine was a pump to a spigot in the stern of my boat. The pump was located about 5 feet from the stern and offset from the keel. I had a ball valve to the opening.
If you install a larger diameter hose you will still only have 3.5 gpm but your pressure will decrease since you are not restricting the flow.
I have one lacated in my anchor locker and use it to rinse the anchor and chain as it comes back in on the windlass it has plenty of pressure but since I boat in salt water I don't use it for cleaning the decks.
I read one of your post from last year about the physics..and one gentlemen said 15' of hose 3/4" really was the ticket...thats what i want.
I will have no livewell on the boat..I have a cooler with a plug on the bottom on my "leaning post" seat. I really want to be able to wash fish guts/ dirt off the deck with a wash down..and if need be I can run that water in my Large Coleman marine cooler that will store my catch.
whatever diameter fitting is on the pump will give you the rated pressure. if you incresae diameter you will decrease pressure, conversely if you decrease diameter you will increase pressure and decrease flow.
mine works fine for what i use it for. I did replace the nozzle though. I need to got to the boat in a few I will see if I can get a couple pics for you.
here are the pics sorry about the quality I took them with my cell.
The pump is mounted in the engine room about 28ft from the anchor locker.
where it mounts to a quick disconnect with smaller diameter hose.
