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Old 06-01-2015, 09:36   #1
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Join Date: Nov 2011
Location: Verona
Boat: Lagoon 440
Posts: 25
Keel construction

Hi 440 owners,

I have just discovered something interesting on my Lagoon 440 and would like some opinions.
Initially when I looked into the bilges it seemed to me that the internal shape is the same as the external shape i.e. the keels are empty and openly connected to the hulls. This worried me a bit because if I ever hit bottom with a keel the hull will fill up immediately.

Today while inspecting the bilge area just under the aft end of the forward cabin bed I found a 5 cm hole, just under the bulkhead, where the front of the keel connects with the hull. Putting a finger in the hole it seems there is a hollow space between the internal keel wall and - I guess - an external wall.

Do you think the whole keel has a double wall?
If so, in my case the whole hollow space is full of water (not sure where it came from) so I guess I'd better find a way to pump it out.
Has anyone considered putting an automatic bilge pump in order to keep the hollow empty of water?

I am happy to have a double wall for safety, but in case the outer wall gets holed the 5cm hole I discovered would still fill the hull pretty quickly, so what is the point? In particular considering that the bulkhead blocks easy access to the hole, so there is no way it could be plugged in an emergency.

Should I instead empty it of water and plug the hole now?

Any other thought is very much appreciated!
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Old 06-01-2015, 09:53   #2
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Location: Presently on US East Coast
Boat: Manta 40 "Reach"
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Re: Keel construction

I am assuming that your Lagoon does not have sacrificial keels.

It is common in bilge keel designs to have fore and aft watertight bulkheads built into the keel. So the inside dimensions of your sump should be less than the outside.

These bulkheads have two functions: 1) prevent water ingress to the hull if you hit and breach the leading or trailing edge of the keel 2) provide strength for standing the boat on the keels on the hard.

I don't know how water got in yours - could it come from the 5cm hole you have? It also could come from an incomplete glass seal around the bulkheads in the keel.

Is there water in the other keel also?

Can you drain it out through the hole? If so, fill the bilge with water and see if it goes down over time.

Normally, there would not be any holes or way into these crash compartments. You might consider installing a sealed access port where the hole is.


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Old 06-01-2015, 10:37   #3
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Join Date: Jul 2009
Location: in the world
Boat: csy 44 tall rig.
Posts: 3,108
Re: Keel construction

If i remember well they are foam filled.. Inner and out layers of glass with a foam core in between..
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Old 08-01-2015, 05:18   #4
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Join Date: Jan 2013
Posts: 312
Re: Keel construction

I'm not sure from your description exactly where this hole is located, but..
1. Directly below the inspection cover that lies underneath the large drawer under the forward berth is where generally the speed depth and temp sensors are accessed. They are located externally just forward of the keel/hull junction.
2. I assume the hole lies slightly more aft of this and would be seen when lifting the floor panel in the forward cabin?
3. I would be of the view that you need to inspect the hole and define its size, clarify that the water is sea water or otherwise, drain it and dry (perhaps vac bagging) and then repair. For $20 so so you can buy an LED lit flexible USB camera that has a cross sectional diameter of 1cm that would be ideal for inspecting the hole. Mine has been invaluable.
4. I'm sure it is not good and needs to be repaired.
5. Salt water could only get there either from a breach in the external layer or perhaps trickle in from the forward bilge when you insert and remove the speed unit at the thru hull fitting, or perhaps from the drain from the forward collision compartment depending on where you have the pipe and ball valve positioned in relationship to the hole.
A photograph would be good.

Good luck
"Second Wind"
Lagoon 440 Hull #30
Brisbane, Australia.
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