The original design the C&C Landfall 38 came with a total fresh water tank capacity of 104 gallons. The total capacity was comprised of 3 tanks. There are two 32 gallon tanks, one each under the port and starboard settees, and a 40 gallon tank under the v-berth. At present, S/V Johanna Rose has only two water tanks limiting the water capacity to 64 gallon. The v-berth tank was removed to provide additional storage space.
Checking Water Tanks for Leaks
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| Port settee water tank. |
As part of the fresh water system restoration, the two settee water tanks were tested for leaks. It turned out the tank on the port side suffered from a large leak due to a long crack along the narrow side along the hull. The photo below shows water flowing out past a bulkhead due to the tank failure. The test of the starboard settee water tank revealed that the starboard tank has no leaks at present.
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| Port settee water tank leakage during water leak test. |
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| Starboard settee water tank during water leak test. |
Water Tank Repair #1 (UPDATE: failed attempt)
[ Using G/flex epoxy and 5200 may work for minor leaks is stress free places ]
[ For a more robust repair see section on welding below]
The water tanks are made from polyethylene. Historically, it is said that nothing sticks to polyethylene. A somewhat new epoxy from West System, G/flex 655 epoxy, claims to be able to adhere to polyethylene. West Systems folks have a great online video of a kayak they cut in half and epoxied back to together. If you have not seen it, it is a must see.
The following is the procedure used to repair the water tank with G/flex. It is based on useful information found on the West System website. I finished the job by covering the G/flex repair with a thick layer of 3M 5200. I had about 3/4 of an old tube of 5200 stored for some time in a freezer, and while the 5200 is most likely not needed, the 5200 will provide some extra stiffening and a bit of insulation from thermal stresses.
- First, holes were drilled at the ends of the cracks to stop the crack from getting any larger.
- The area above and below the crack was cleaned by sanding with 80 grit sand paper.
- A Bahco tungsten carbide scraper was used to bevel a vee and open up the crack to increase the bonding surface area and to reduces concentration of stress on the joint.
- Using 80 grit paper, sand and round the crack opening and crack underside so that the crack has rounded edges.
- Clean area with alcohol wipes.
- Flame treat a plastic surface.
- Hold a propane torch so the flame just touches the surface and move it across the surface at a rate of 12 or 16 inches per second. Keep the torch moving and overlap the previous pass slightly. When done correctly, the surface will not discolor or burn in any obvious way. This technique oxidizes the surface and improves adhesion. For best adhesion, bond to the surface within 30 minutes of treatment.
- Mix G/flex epoxy and apply to crack throughly over filling the bevel area.
- Let epoxy set.
- Clean and wash with alcohol.
- Apply a thick layer of 3M 5200 and smooth out slightly wetted with alcohol.
- Let cure, flush clean interior volume, and leak test.
- Reinstall tank and reconnect water lines
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| Underside of port water tank. |
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| Port settee with water tank removed. |
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| The tank crack in the port water tank. |
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| Drill hole to arrest crack. |
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| Drill hole to arrest crack. |
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| Crack grooved, sanded, torched, and cleaned with alcohol. |
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| Preparing the crack for epoxy. |
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| Preparing G/flex epoxy. |
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| Applying G/flex epoxy to repair port water tank. |
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| Port water tank repaired with G/flex epoxy. |
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| The completed repair |
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| The job was finished by covering the G/flex repair with a thick layer of 3M 5200. |
UPDATE!!!
Repair #1 quickly failed. I did some more research and found the the best solution was get a hot air plastic welder and weld repair the tank.
Water Tank Repair Using a Plastic Welder [Recommended Repair]
[UPDATE: As of Oct 2016, the repair tanks are still leak free. This included a 580 NM trip most of which was offshore with much of that beating into wind and waves]
This is the fix that has lasted. The tank was repaired using a plastic welder. The welder has a nozzle with an electric heating element that is connected to an air supply. In this case, the air supply was provided by the output of a small vacuum pump. The air must be constantly flowing otherwise the heating element will burn out. I was able to borrow this hot air welder, but the unit is not much different that the hot air plastic welder sold at Harbor Freight Tools (See their 1300 Watt Plastic Welding Kit with Air Motor and Temperature Adjustment). Since the water tank is made from LDPE, LDPE welding rod 1/8" thick were purchased for the task (Grainger Supply #4VDA6). To provide added strength to the welded repair, reinforcing stainless steel mesh was added and welded onto the tank surface. The wire mesh was purchased at Grainger (#3AMD7).
All I can say is that practice welding on scape material first, and before long anyone can be an expert.
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| Section of plastic weld completely filling the crack in the tank. On top of the weld, reinforcing stainless steel mesh was added and welded onto the tank surface. |
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| Plastic welder: The device is a electric heating tip with hot air blowing through. The propane torch is also useful for filling a bulk void with welding rods, but otherwise it was not used. The photo also show the package of 1/8" LDPE welding rods purchased from Grainger Supply (#4VDA6). |
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| Close up view of repaired tank with reinforcing stainless steel mesh. |
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| Repaired water tank ready for installation. |
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