How collapse resistant is that flexible PVC. Of course, it also depends on what type of pump and where the pump is located.
This is the flexible schedule 40 PVC. It's is vacuum rated for 28" of Hg (381", or, 31.8 feet
of water), and has a working PSI of 65, with a burst pressure of 200 @ 68ºF. This should be more
than adequate for the manual pump, which is in the cockpit. The smaller of the two ribbed hoses that you see in my pictures above is for the electric pump, and the larger is for the manual pump.
The electric bilge pump is in the bilge (surprise!
- Shown here before I bought the boat, and before the keel bolts were replaced.
You would need to get an adapter to change the diameter using a short pigtail. However, be aware that such adapters generally restrict the inner diameter of the hose a bit and can become a source of clogs. Just clamping down on the hose isn't going to work very well and the setup will generally leak.
I am actually considering using a smaller diameter hose for intake
of the manual pump.I would step it up to 1½" hose just before the pump. Assuming that I don't change the manual pump, decreasing the diameter of the hose would increase the velocity of the water flowing through the hose, and increase the amount of room that I would have to work in the bilge.
If I increase
the diameter of the hose from the electric bilge pump, from 1-1/8 to 1½, I would expect that I would also decrease the likely hood of obstruction. I guess that I will also need to change the size of the through hull.
I'd stick with all hose and run it continuously if you can. Additional joins and piece all become another place for leaks and failure.
Again, this is schedule 40 PVC. I have never had an issue with joints breaking, assuming that they are primed and cemented properly.
However, I think that I could change the routing of the hose, and not need them. Both hoses run down the center of the bilge, until they reach the engine bulkhead. There they turn 90º to starboard for about a foot, then they turn 90º and run aft toward the transom under the rear quarter berth. The electric bilge pump's hose runs directly out the transom, and the manual pump's hose rises to the cockpit, where it connects to the pump.
Regarding the cable runs:
Agreed... I don't like cables in the bilge at all, but there are some cables that must run into the bilge; like the (keel stepped) mast wiring (VHF & nav. lights) and the bilge pump wiring. Bangor Punta put the current holes in the stringers 24 years ago.
Why were the other wires snaked through the bilge, you ask? Because, I believe that the PO paid a yard to install a vacuflush head. The yard ran the wire the easiest and fastest way that they could (cheap, shoddy workmanship - by "professionals")