This Article was created by Doug Jorgensen
With the ongoing concerns regarding staining of floorboards and pending corrective action, outlined below are some modifications that have been made to Hot Tamale to help minimize water in the bilge in the first place.
Water in a flat bilged boat (are there any other kind?) always presents a drainage problem. The flatness of the bilge, the fact that boats heel and the presence of both fore and aft as well as athwartship hull stringers pretty much prevents the possibility of complete drainage to the keel sump where it then be pumped overboard. On Hot Tamale we have taken 3 or so specific steps that maintain the bilge in a dry condition and are as described below, along with some additional comments/ observations:
Drainage from stuffing box and ice box to the keel sump: Stuffing boxes drip by design. They are “stuffed” with grease impregnated flax or synthetic material and need to drip something on the order of once every minute to provide proper water lubrication and to insure that the material is not so tightly packed that friction and heat do not become excessive. The rates at which they drip increase when the engine is running and after the engine is turned off the stuffing box can drip at a higher rate for a period of time. The boats as they are delivered from the factory depend on draining forward from the stuffing box thru about 5 athwartship stringer limber holes on its way to the keel sump. The ice box drains into the bilge as well at a point closer to the keel sump but it presents the same drainage issue. We installed a 3/8 dia plastic tube that runs from the first limber hole forward of the stuffing box thru all the other limber holes forward the keel sump. The tube is sealed around its perimeter at that first limber hole. We also “picked up” the ice box drain line by connecting it in with a fitting along the way. The result is a much dryer bilge in the flat sections aft of the keel as it picks up these known sources of water that ends up in the bilge. This is an area that can’t drain well no matter what, so preventing water from accumulating in the first place works very well. Replacing the stuffing box with a dripless face seal design can eliminate this as a source of water as well, which is an additional mod. that we did at a later date.
The keel sump: The bilge pump set up works well with an “auto” position that keeps the water level in the sump down to a few inches. The float switch can’t be set up to remove any more than this as it would risk running continuously dry if misadjusted even slightly. Some additional water can be removed by running the pump in “manual” position until the pump loses suction, about 10 or 15 seconds, but there is still about a gallon or 2 of water remaining. The problem with getting more complete drainage is mainly related to the size of the bilge pump hose, the height of the anti-siphon loop and the volume of water that drains back after the bilge pump stops. We passed on using a check valve as hair and debris might either clog it or at a minimum cause leak-back which would would drain the contents of the hose back into the bilge in short order anyway. Our fix: We installed a small ½” 3 way selector valve from the shower sump that selects suction from either the shower sump or from a ½” plastic tube that is routed to the valve from the lowest part of the bilge sump. This arrangement fits nicely and is accessible from the forward most removable floorboard cover in the main cabin. Turning the valve to the bilge position and then activating the sump pump from its button in the head pulls just about all the water out of the bilge sump with about zero flowback. In addition, we blanked off the drain fitting in the head sink and routed to a tee fitting installed into the drain line under the sink. I’m not sure about the compatibility of the shower sump pump with seawater, but this has worked perfectly for 3+ years. The existing strainer is kept in the common line to the pump and needs to be cleaned periodically for either service.
Water tanks: When filled completely the height of the water from the deck fill creates pressure and a lot of distortion of the plastic water tanks, especially the unsupported flat top. Ours leaked from 3” dia threaded access plugs. The access plugs are molded plastic and the threads have a pronounced amount of flash or raised plastic that prevents a good seal. I removed the plugs P & S, sanded down the raised part in the vee of the thread carefully and reinstalled using 3M 5200 on the thread. I did this recently so I don’t know if this should do the trick. 5200 takes a long time to cure so allow about a week before filling the tanks to the max.
I often remove the 2 aft floorboard covers when I leave the boat to promote air circulation and I sponge or towel out any water in the flat of the bilge.
Forward of the bilge sump drainage seems to be less of an issue. When we get a lot of water thru the forward hatch or pull the speed transducer water more or less seems to drain ok. We leave the drain valve to the sealed compartment under the anchor locker forward open and this area is tight so water it does not leak from this area. Some boats report that this area leaks and water draining from this area is a problem. It sounds like steps need to be taken to locate and properly seal any water leaks into this area. One thing that we have noticed is that the compartment under the drawers, forward cabin starboard side, does not drain. Any water that gets here has to be sponged out. The same is true for the compartment under the seat opposite the head. This is not really a problem as its rare that much water would enter the boat thru the forward hatch.
Additional topic: Galley sink drains: The drainage of the sinks the way they come from the factory allows water to drain from the high side sink into the low side sink rather than overboard when the boat is heeled. This bit of annoyance can be fixed by lowering the point at which the drain lines from each of the sinks connect. Picture 005 below shows rearrangement of sink drain plumbing that accomplishes this.
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This section includes pictures and descriptions associated with this article. The attached pictures may be expanded by double clicking them.:
Shows plastic drain line that runs thru limber holes adjacent to
sink area and the connection of ice box drain into drain line.
Picture taken
port side of table.
Shows plastic drain
line
entering
sump
area
on right,
shows extra
suction line
from bilge sump area going forward on left.
Engine compartment. Dripless shaft seal on right.
Underneath the
rusty
shaft connection
to the transmission on the
left is the
athwartship engine support stringer. This is the point at
which the
½” drain tube starts. It is sealed in
place around
its
OD
as it passes
through the drain hole.
The end of the
drain tube
is flush to the
face of the
stringer.
I could not get a picture of this.
Close-up of dripless shaft seal.
Just aft of main
cabin forward bulkhead. Shows selector valve for pump for
shower pan
to pull from
either shower sump or from bilge sump. This arrangement allows
almost complete
removal of water from the bilge sump.
Under galley
sink. The point at which the sink drain lines connect to the
common drain
overboard has been lowered. Water in the high sink no longer
finds its way into the low sink when the boat is heeled.
Comments:
A dry bilge is a happy bilge. What I described above will keep a boat from having any bilge water related problems for most types of use that the boat sees. However, on a wet distance race water through the hatch, soaked people and sails below, water will find its way to the bilge in a heeled boat where it will stand and create problems with the floorboards from underneath unless they are properly sealed.