I am helping get a 7 metre catamaran back in the water. It will be doing river and coastal cruising, but will be sitting on a mooring year-round. I'd appreciate your advice on fitting bilge pumps.

There was a good thread elsewhere on considering what the aim of the pumps will be so I'm under no illusion that they will be much help if it is seriously damaged - more trying to make sure that the rainwater and spray that inevitably get in are reduced while sitting on the hook.

There are lots of tutorials on YouTube but they seem to all be for little powerboats that go back on the trailer at the end of the day.

My questions are:

1. Skin fittings: does anyone have any data or stories with regard to material (nylon/bronze/stainless) for an above-water drain?

2. Seacocks: none of the videos show fitting a seacocks, but I'm not sure this is wise for a boat permanently in the water. Am I being too paranoid?

3. Drain location: trying to keep the opening above the heeling angle, which I know is not huge on a catamaran anyway, it seems to me to be better to place the drains on the inward aspect of the hulls (under the trampoline) than outward. Plus this way a wave hitting the side is less likely to send water back down the drain. But it's harder to see them and check them this way. Any thoughts?

I'm trying to talk myself out of just using a float switch and instead having a manual override option as well, but mounting a switch is a bit of a pain so I'm not sure that will be worth it.

Thanks for your input!

The main killer to effectiveness of bilge pumps is head/height as they are mostly centrifical pumps. So, good news is that with little draft on Cat hulls, you don't need to achieve a high head.
you can put the outlets on inner hulls. Less likely yo be hit/damaged but they still will get wave impact (ask me how I know!) so you will need to fit seacocks. Make them easily accessible Tru-Design composite skill fittings and seacocks are good quality.
The wiring will be a pain as you need two separate switches so you can over-ride n test each pump/hull.
Id go with Rule or similar with enclosed switch. Just test em every time you are on the boat - easily done. They do fail over time but you'll get years of reliable service.
The main killers for centrifical pumps are foreign bodies. Cable ties will slide an edge past the grille, or hair from a poorly designed shower sump will cover the pump vanes. Keep 'em clean!

My yacht has the usual two manual pumps and a 12v pump as a back up. For sitting on a mooring and clearing any rainwater etc from the boat while I'm away I have a completely separate system. This has it's own solar panel and controller and a lead acid car battery, Waterwitch electronic switch and an 800 Rule pump with an extra mesh covering. No switches and completely separate from the ships 12v system. All the pumps are plumbed into the same pipe which exits the hull at the transom which on an SS34 with wheel steering means you can easily see when the 800 rule pump is on.

We had a 30 ft flybridge cruiser not long ago. ( June )
Three auto bilge pumps...one manual.
On a mooring.
Exy VSR electrical system. ( 6K )
Three batteries....2 740CCA. Start batteries,
one 1000 CCA deep cycle house battery

Sank in a gale force storm at night...gusts of 45 knots...4 metre swell.

Once water started coming over the bow it was only a matter of time till the batteries or the bilge pumps failed.
Thats a guess.

If your mate can find a pov pack berth consider taking that instead of a mooring.
Moorings are a pita at the best of times.

If l had kept the $25 a week poverty pack marina berth l would still have my boat now.

At the moment there is another boat sitting on the bottom, after another fierce storm.
No berthed boats have sunk in the same time frame, whereas l know of 5/6 moored boats either sink or broken their moorings...l actually got one on video as it broke away in really, really strong winds.
It ended up on its side.

Something to consider

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tired said..
We had a 30 ft flybridge cruiser not long ago. ( June )
Three auto bilge pumps...one manual.
On a mooring.
Exy VSR electrical system. ( 6K )
Three batteries....2 740CCA. Start batteries,
one 1000 CCA deep cycle house battery

Sank in a gale force storm at night...gusts of 45 knots...4 metre swell.

Once water started coming over the bow it was only a matter of time till the batteries or the bilge pumps failed.
Thats a guess.

If your mate can find a pov pack berth consider taking that instead of a mooring.
Moorings are a pita at the best of times.

If l had kept the $25 a week poverty pack marina berth l would still have my boat now.

At the moment there is another boat sitting on the bottom, after another fierce storm.
No berthed boats have sunk in the same time frame, whereas l know of 5/6 moored boats either sink or broken their moorings...l actually got one on video as it broke away in really, really strong winds.
It ended up on its side.

Something to consider

That sounds like one hell of an exposed mooring field ! May I ask where ?

Tasmania, east coast
No good in north or north westerlys

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tired said..
Tasmania, east coast
No good in north or north westerlys

My money is on a failed float switch.

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Ramona said..

tired said..
Tasmania, east coast
No good in north or north westerlys

My money is on a failed float switch.

Dosen't matter now but the boat had THREE automatic bilge pumps, which were all working prior to the event.

There was two new unopened bilge pumps on board as well, just in case.
LOL
My money is on the battery failing after hours of cycling in extremely heavy weather...at night.

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tired said..

Ramona said..

LOL
My money is on the battery failing after hours of cycling in extremely heavy weather...at night.

The battery drains from the constant restarts. The Waterwitch switch only switches on when it is needed.

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The battery drains from the constant restarts. The Waterwitch switch only switches on when it is needed.

The battery went flat from constant use...apparently.

The insurance company seemed happy with that probability.
Specially after talking to marine professionals who knew and had worked on the boat over the years of our ownership.

**** does happen...specially on moorings in storms.

Thanks Bushdog, I hadn't figured on the need to have the inlets closed while underway but especially once out of the river it is probably worthwhile.

Any thoughts on the Tru-Design check valves? I don't think it lets us skip the seacocks but might let us keep them open more often?

tired, interesting to hear, luckily the mooring is fairly sheltered, we have seen a boat sink in the pen in the club although it's fairly exposed to the prevailing weather.