I was thinking about changing the 1 1/4" water hoses from my sea strainers to my water pumps from the thick hard to bend water hose to some silicone hoses. They appear to be more flexible and appear to be easier to use. Has anyone used these in this application or have any experience with them?

From sea strainer to raw water pump? If those silicone hoses are not reinforced the pump will collapse them when running. I collapsed a garden hose early in my boating life when breaking in a pair of engines not realizing how much water those pumps can flow. My thought process was to keep the hose from coming out of the 1-1/4" line by accident, so i duct taped it around....start engine and rev it up to 2K rpm....all going good till i start seeing steam instead of water coming out....look over thinking the hose somehow popped out...nope flat as a sheet of paper!!
It maybe easier but not necessarily better.....

pressure side yes suction side no

Not sure what hoses you are looking at but the ones I've seen were too flexible IMHO. When running in rough water, everything needs to be secure. Wiring hoses, batteries, everything. You don't want to loose a water hose, especially at speed. The bilge can fill up very quickly if one pops. You have enough potential disasters working against ya being a boat owner, don't need to add anything else.

If you use none marine rated hose and your chit goes to the bottom of the lake dont call your insurance guy...........

I tried to use silicone water lines on my pool pump many years ago and as others have said, had the same experience...just sucked it flat as a flitter.

I think Parker makes a reinforced but more flexible hose. Looks like it’s ribbed on the outside for our bending pleasure. Check that stuff out.

All the comments given was what I was worried about. I did run the boat for about 1 hour this weekend with the silicone hose on it with no issues. I will change it back out to the reinforced wire hose just to be safe.