Originally Posted by Ziggy
That's interesting. I'm surprised the manual pump can suck through the electric
... What kind of electric
do you have?
Most leisure craft submersible bilge pump
are of a basic centrifugal type see Google
Properly sized when not operating they offer little resistance to the flow of water
feeding a manual pump. They are equipped with a strainer so there is no need for, and it will save the weight, of a nice bronze strum box. The electric pump
is sized for the full load not half load, the second electrical
pump is of the same size and work as an instant back up working together they pump a greater volume of water
. An electrical current
reading of each pump give an indication of how well they share the load and of the amount of water pumped. Non return valves are part of the pumps and are included in the rating capacity of the pump if properly maintained they are reliable and do not leak sufficiently to impair on the capacity of the pump. I use a manual pump to vacuum my water tanks
for a quick fill. Whale pump do hold a vacuum other brand do not, good to check at the chandlery
. The regulation for my region says that I should have a manual pump able to pump 100 l/min. The pump that I can purchase
is only rated at 80 l/min by having two pump in series I create a double acting pump and easily satisfies the regulation. Other regulation demand that a manual bilge pump
should be able to be operated from the cockpit
and also, should discharge into the cockpit
witch is good. I like to be able to see easily how much water is getting pumped out. Interestingly the regulations
say nothing about having the manpower on board to operate the pumps. I doubt that a mobile bilge
pump would be suitable in heavy weather
. It can be estimated that a 51mm sounding transducer 1 meter below the water line popping out can let up to 300 l/min into the boat. Test conducted by a boating
magazine came up with the figure of 220 l/min, as the boat think the water inside the boat slow the ingress of water. Trying to pump that amount of water with a manual pump would by hopeless. As pointed out.
Originally Posted by Ziggy
If the electric pump
is functioning and water is flooding in, I'm better off occupying myself with damage control than sitting at the manual pump. Even with adrenaline flowing, I could only operate the manual pump for a limited time anyway.
When using the electric pump, the manual pump in the cockpit can be easily bypassed by the use of a ball valve easing the flow of water. Like many cruisers in this forum I do have the possibility of pumping the bilge
with the Main and or the Generator engine
so starting one engine
would be one of the priority with the advantage of getting a higher voltage to the electrics pumps.
At 220 l/min my boat would sink at the rate of 8.5mm /min after 70min of doing nothing it will be time to get the life raft ready.
Originally Posted by bewitched
The important thing is that you are comfortable with what ever system you go with.