raw water blockage

[Administrator]

A one-inch hole 12 inches below the waterline will flood the boat at a rate of 19 gallons per minute. For a two-inch hole, it's 78 gallons per minute.

Reference here, with some interesting links to info on bilge pumps at the bottom.

Bill

[Ando]

Thought about going to get an air compressor to blow it out but then it occurred to me to try connecting the bilge pump outlet to the hose and pumping water back through it. Had to dump a few pails of water in the bilge but it did the trick. A large jelly fish came up once it cleared

No diving required

Hope that helps

Peter

What’s the size of your pump?

[Peter]

Pump is a Rule LP900S LoPro 900 GPH

Which seems like a pretty small gph if a “ A one-inch hole 12 inches below the waterline will flood the boat at a rate of 19 gallons per minute”

However it did the trick for clearing the thru hull

Had to flood the bilge about three times to fully clear the jellyfish though.

Peter

[Administrator]

Pump is a Rule LP900S LoPro 900 GPH

Which seems like a pretty small gph if a “ A one-inch hole 12 inches below the waterline will flood the boat at a rate of 19 gallons per minute”

However it did the trick for clearing the thru hull

Had to flood the bilge about three times to fully clear the jellyfish though.

Peter

I think the success here may have had more to do with pressure than volume.

Bill

[Ando]

I think the success here may have had more to do with pressure than volume.

Bill

You think 750gph would do the trick?

[Administrator]

I think 10 GPH would do the trick at sufficient pressure.

Consider a "plumber's helper."

Bill

[Peter]

Indeed pressure was the answer in blowing that jellyfish out.

My comment about flow rate being inadequate was parenthetical - I simply had realised from the link Bill provided that one cannot rely on a bilge pump to stay afloat in the event of a hull puncture. From the site Bill referenced

All of these numbers allow us to plan for the unthinkable.

1. Few bilge pumps are suited for saving a boat that has a sizable hole below the waterline.

2. Hole size is the major determinate for how long your boat will float after being holed.

3. Your primary effort should be aimed at reducing the flow of water into the boat. Plugs and collision mats are your best bets and deserve to be aboard and part of your primary hull-hole toolkit.

Stay safe!

Peter