High water Bilge pumps

[b-rad]

I'm installing 2 additional bilge pumps for a emergency situation. Boat is a 43 foot sailboat with a very deep bilge, (5.5 feet deep) if it was full before you caught it your sunk.
The boat has 2 bilge pumps already. A 1200 and a 2000 mounted in the sump.

Here's my plan if anyone wants to give input or advice I'm open.

Wired direct from battery to bus bar.

2 rule 3700 pumps with 2 seperate enclosed auto switchs each wired to bus bar seperatly.
I'm thinking of mounting all this inside a plastic tote and drilling 2 inch holes around the tote for water flow.
The box would be mounted to a shelf in the bilge about 8 inches above the sump where the other pumps are. I don't have a manual pump and don't want to argue about that here. But I do have a 2 inch throughhull outlet where the manual pump once discharged. I'm thinking of a Y here and exiting both 3700s. I know that the 3700s will be lucky to push 3000 once you account for the 6 ft of lift and 6000 gph pumps use a 2 inch through hull, thoughts on this plan?

I also have a separate high water alarm with its own float swich. I'm torn between putting this in the box attached to the bus bar or wiring it on it's own.

[Steadman Uhlich]

I think you are smart to add more bilge pumps.

What follows is written in a friendly tone of voice, and with the sole intent to help you with a different POV.

If your goal is redundancy for the sake of safety and emergency response, in case of failures (a good goal for mission critical systems), as general principles I would:

1. focus on keeping the system as simple as possible

2. would not "bunch" things together.

I would have separate power sources (which is why manual pumps are so often recommended in addition to electric) and I would NOT co-locate or depend on a single input or output or a joined (y valve) point of failure (electrical or plumbing or switch).

3. I would test the system. I would test in a marina (easy) and while underway, with the boat heeling on both tacks.

I hope these comments help you.