Bad leak in sailboat

[openseas]

Hi All,
I have a 30" Siedlemann sailboat, that I had problems with leak since I bought it 4 years ago. The marina did many repairs, but I believe they didn't find the source of the leak.
One say they told me me that it was the prop shaft, and changed it with the housing at a cost of $3000+.
Last year I was sleeping on the bought in the marina, and at night I turned on the water pulp to empty any water in the bottom of the boat, I let it run for 2-3 minutes, and then turned of and went to sleep.
Ten minutes later the boat was taking water at a scary rate, which I believe that within 5 minutes or so, the boat took over 100 gallons or more.
I frantically let the bilge pump run for over ten minutes before it controlled and stopped the water that was coming in.
I am so frustrated from expensive repairs that didn't do anything to the leak, also I don't want to sell the boat to anyone knowing that it still has this problem.
I have two questions for you the experts out there:
1- It is possible that the water is coming through the hose of the bilge pump, which means a reverse flow of the water ( by the way, the hose of the bilge pump opens 2-3 inches below the water level). And also the boat doesn't have any hull cracks at all.
2- If there is a chance that the water flow is happening in the siphoning system ( I am not sure if this is the name for the bilge pump hose system) and I want to correct it, do I need to do it when the boat is on land or in the water.?
Thanks a lot,
Andy

[DeepFrz]

I bet it is siphoning back in the bilge pump hose. The through hull for a bilge pump should never be below the water line, IMO, for just this reason.

[Captain Bligh]

X2

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[DumnMad]

Blocked or stuffed syphon break.

[DeepFrz]

I do believe that the bilge pump outlet should include a siphon break, but the through hull should not be below the waterline on an even keel. The siphon break should be needed only when heeled if the outlet is then below the waterline, which is still a bad design, IMO.

[HopCar]

I think Deepfrz nailed it.

Here is a link to the Rule bilge pump instructions.
Scroll down to page 14. That is what yours should look like.

The vented loop should be well above the heeled waterline and the outlet should be well above the level waterline.

The vent in the high point of the loop lets air into the hose which breaks any siphon that might develop.
http://www.xylemflowcontrol.com/files/950-0518.pdf

[Jim Cate]

Hmmm...

Do you even have a vented loop in the discharge line? Don't think that you said anything about one...

Jim

[DumnMad]

Even if sump pump through-hull is above the waterline on an even keel, it may not be when you are sailing.
With through-hull below the even keel waterline you are more likely to find the siphon fault at the berth than when on deck sailing and not so aware of pumps going on and off.

[stevec195]

Also, if you have a PSS shaft seal check the cooling line that supplies water it should have a vented loop. Also look at the stainless rotating collar that seals at the graphite block on the shaft itself for proper adjustment.

[Terra Nova]

Hire a professional.

[Badsanta]

You need to look around. Check all hoses, thru hulls and valves. Does your bilge pump start
automatically? I have seen the bilge backfill if installed wrong. One almost sank because there were more people in the cockpit than normal and it lowered the boat enough to reverse flow. Any similarities to each flood?
Even if you cant fix it, try to narrow the causes down.

[onestepcsy37]

sounds like you already got ripped off on the prop shaft. i just had mine done by my yard in titusville; new shaft, new cutlass bearing, new tranny adapter, all labor in and out, $900. this on a 37 foot boat with a 50hp engine.

bilge pump should be easy to check. reroute the outlet to higher up on the hull. maybe a temporary hose that just dumps into the self draining cockpit or even over the side of the cockpit. block off the existing through hull. this is not an expensive procedure and definitely does not require a 'professional' to look at.

[openseas]

Does the boat have to be on land, to take care of this job?

Andry

[onestepcsy37]

if you're going to remove a hose from an underwater through hull fitting, you can insert a wooden plug in the through hull from the outside, then remove the hose from the inside. then i would try to plug the through hull from the inside too.

once the underwater fittings are well sealed you can go to work on the rest of the system.

[Jim Cate]

Originally Posted by onestepcsy37

if you're going to remove a hose from an underwater through hull fitting, you can insert a wooden plug in the through hull from the outside, then remove the hose from the inside. then i would try to plug the through hull from the inside too.

once the underwater fittings are well sealed you can go to work on the rest of the system.

But surely there is a seacock on the throughhull... isn't there? If so, no need for all that strife, just close the valve and disconnect whatever needs disconnecting.

Cheers,

Jim