Steel Sailboat - deep bilge

[Briarpatch]

I have a Roberts 36 Cutter that has a very deep (all the way to the bottom of keel) bilge. The bilge space is between two frames (about 30in apart). Running lengthwise along the top of the 1/2" thk. keel plate is a 3/8" x 3" flat bar strong back. This strong back splits the bottom of the bilge into 2 longitudinal sections (port and starboard). If I install a bilge pump on the port (or stb side for that matter), the bilge pump will never pump out the 3" of water on the other side of the strong back.

I really don't want to install bilge pumps on both side of the strong back (unless it is necessary).

Has anyone out there filled up a space (3" high x 5" wide x 12" long - don't ask, the keel ballast area takes up about 18" of the bilge length) like this with a grout, epoxy or any other pourable product that will set up hard, bond well with steel and prevent sea water from contact with the true keel bottom? If so, what kind of pretreatment is required of the bottom?

[boden36]

Many years ago when we put the ballast in our yacht's keel we poured molten tar around it. It never goes rock hard and is still excellent after 30 yrs. A dangerous process though.
From memory we abrasive blasted and primed the plates first.


Regards,
Richard.

[coopec43]

In my yacht (which is under construction) I have suspended my expensive Rule bilge pumps 6 inches above the bottom of the bilge. (Doing that I hope they will never get wet!!)

To get rid of any water the large bilge pump cannot pump I will install diaphragm pumps which can pump 5 lpm and cost only about $25 ea on eBay. These pumps will be switched on manually.

Clive

[hpeer]

Similar situation in a Brewer “Murray 33”. I ended up turning that void into a fuel tank. I had a hell of a time trying to prep it properly, it woul always rust. So I made it a fuel tank. Two actually as I had 2 bilge sections.

So here is what I would consider. Use aircraft fuel tank sealant. It’s available from either Boat Life (the caulk people) or much cheaper from aircraft stores. 3M and Flamemater and others make it. It comes in a variety of dispenser containers, is a two part goo. It comes in a “flowable” or “vertical” consistency. The vertical consistency will close a 1/4” crack!

https://www.skygeek.com/flamemaster-...k-sealant.html

So read up on this stuff. Or call Flamemaster and ask if you can pour it 3” thick.

If you turn your keel into a fuel tank you may want to make sure you have no communication between the good sections and the adjacent ballast sections. If you do have communication or are not sure you may want to seal the bottom of the tank with this too to assure separation. Or not and let the diesel permeate the ballast.

As always pros and cons.

[txg]

Originally Posted by Briarpatch

I really don't want to install bilge pumps on both side of the strong back (unless it is necessary).

This is a setup you should be happy about! Install two pumps, with separate outlets that you can see while in the cockpit. If one of the pumps starts to run, you have instantly cut the area where you need to search for a leak cut in half, which is worth A LOT. On the other hand, if one of the pumps fails it is no big deal as the second one will still work.

[boatman61]

A Bruce Roberts 54 I delivered dealt with the bilge depth by prepping the steel then coating it.. with what I dont know.. they then poured in liquid foam to the level required and topped it with an epoxied ply laying on top sealed round the edges with 5200.
This was the centre section which stayed dry.. fore and aft they left a section deep to act as collectors with auto bilge pumps

[Russ]

Agree twin bilges do help identfy leak area. Does arrangement not allow for limber holes between the two halves. Just need a drill. Russ

[Scorpius]

Originally Posted by Russ

Agree twin bilges do help identfy leak area. Does arrangement not allow for limber holes between the two halves. Just need a drill. Russ

Or a cutting torch - which is what we did for a similar situation on Scorpius.

[Donald Bryden]

In building my steel boat I was faced with the same problem. I didn't want voids that were almost impossible to drain and maintain. My solution was pour in-place-foam. If the sides of the space are clean, the foam will adhere to them. At the top, it was easy to shape with a knife and by sanding. After shaping, I covered the foam with West Systems epoxy. After 20 plus years this system has remained trouble free. Another method used by a builder friend was to fill the void with cement. I'm not sure how this turned out as he went into the charter business and I went cruising.

[kapnd]

Originally Posted by boatman61

. fore and aft they left a section deep to act as collectors with auto bilge pumps

This is important!
Even if it’s just a pipe to the bottom, you should always have a way to know what’s going on in a closed compartment.

[qwert]

Faced with a similar problem I sandblasted and epoxy painted the steel sides then coated the side with 1/4 inch of sikaflex (here in aust there is an identical product parfix much cheaper). Then I filled the hole with epoxy bog. The theory of the sikaflex was to give a flexible permanent seal so there wouldn't be cracking between the steel and the bog letting water into the microgap.
Seems to be working.........

[roland stockham]

You should always fit pumps in pairs anyway. They fail on a regular basis. With a deep bilge min 1500gph. anything less will just stall due to too much head. Don't care what the advertising says on the dinky little 1000gph jobs all the ones I have had burn out within 12 months!

Ideally I size bilge pumps so that with a sea-cock open they will keep the bilge dry. That way if you do get a leak you can find it, if it is under a couple of feet of water by the time you get there you have no chance of seeing whats happening.
So I would fit 1500gph pumps in each section plus 4000gph on top of the strong-back as a crash pump. Fit this with a loud alarm to wake you if it ever comes on!

[Mike Banks]

Concrete.


Or--you could close almost all of it by welding or bolting a tank top plate with an in-built bilge sump built in to the tank top. Place this almost at the top of the keel, making it an extra emergency fuel tank.


Which would be my option. It is just trouble waiting to happen the way it is now.

[MicHughV]

Here is what I did on my steel Roberts 38......the back portion of the keel cavity was not meant to have ballast, but I had no idea how I could get in there and apply any kind of sealant.
So, I filled the void full with a concrete mix....you buy a bag of pre-mix concrete at Home depot..mix with water and in it went.
I filled to near the top inline with the other ballasted voids.
After the concrete hardened, I coated it with coal tax epoxy ( as per the rest of my interior) to seal it all in and prevent any water from dripping down the sides.
After many years of sailing it never leaked.
Alternately, you can go to Home Depot and buy several cartridges of foam sealant, you can can also get this 2 part foam sealant, you just place the cartridge in a regular cartridge sealant gun and squirt the foam in there. Follow immediately behind with a trowel to flatten it out.
If you get the 2 part foam, let it expand to the top and trim it after with a saw blade. It will cut real easily. Then seal it with the coal tar epoxy.
Hope these suggestions guide you.

[MicHughV]

oh, I should note...in the keel frames in the keel cavity I had drilled some holes, right on top of the ballast line, so that any water that came into the boat and found its way down to the keel could move between the frames.
One cavity I poured the ballast at a little lower elevation as the other voids.
This became the low point of the bilge or sump and it was the place where i mounted a bilge pump.
I had two pumps in there. An electric pump with float switch and also the tube from a larger hand operated bilge pump. The end of the hose I had fitted with some chicken wire to prevent any large detritus from getting sucked into the hose and blocking the pipe.
Finally, at the time, I had an fridge system that ran off ice. The ice would melt and the melted water would find its way to the bilge via a small hose fitted to the bottom of the icebox. I placed an empty one gallon milk jug in the bilge and ran this small hose to the jug. About once a day, I would reach into the bilge, retrieve the milk jug, empty it and return it.
I never wanted to see water in the bilge. Ever. Seeing water in the bilge to my eye represented a serious problem somewhere.
By and large, I had a dry bilge for a very long time.
On that note, my prop shaft at first had one of those packing glands that allowed a small drip into the bilge. This irked me no end, so I got one of those carbon collar packing glands and the rubber accordion tube, it has a name, but I forget what. Once that was mounted ( at my first haul out) I never had water dripping into the bilge again.
Once in a blue moon, some rain water from an open hatch would find it's way to the bilge, but this I would mop up with a sponge.
A dry bilge is a happy bilge !!