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Ordering new seacocks

Now that the boat is on the hard, the first big project is to replace all the seacocks. Some are still originals (30 years old), others were replaced some time ago with brass and are in a bad shape. There are basically three materials that are considered appropriate for use as seacocks:
  • Bronze
  • DZR/CR brass
  • Composite plastic
After some research we came to the conclusion to use DZR (Dezincification Resistant) brass for the new seacocks. In some places it's also called CR (Corrosion Resistant) brass or labeled as CW602N. Sadly the Swedish chandleries don't sell those. We could only find CW617N, which has regular zinc content and is not corrosion resistant. It's suitable for freshwater systems only and in a salted environment will last only a few years before it becomes brittle and can break, so it's not an option for a bluewater boat. Some shops have bronze and composite plastic (from Tru-Design), but they are much more expensive than DZR brass and some of the fittings (like a T piece) needed on our boat are hard to find. The Tru-Design valves are also bigger than the others, so you need more space to fit them. We decided to go with Maestrini CR-brass seacocks. They are manufactured in Italy and can be found in several shops in the UK and Germany. We ordered most parts from SVB24 from Germany (they had the most competitive prices) and the rest, like lock nuts, a 38mm hose fitting and a T-piece from various places, making sure it's CR-brass and possibly Maestrini. In general ASAP-Supplies has the best selection of various sizes and pieces, but sadly their website was broken for weeks at the time we were ordering. Before ordering I measured all the hoses and hose fittings and the outer dimensions (OD) of the skin fitting threads. Then I used this table to identify the correct seasock sizes in inches (OD actual to pipe thread size). We have 6 skin fittings under the waterline (besides the depth/log transducers, but that's for a later project): Galley 1. seawater intake (1/2") 2. kitchen sink and bilge pump outlet (1 1/4") Head 3. sink outlet (1/2") 4. toilet flush water intake (1/2") 5. toilet waste outlet (1 1/4") 6. Cockpit drain (2") There is one more seacock on the Volvo Penta S-120 saildrive for the engine raw water intake, and it's still the original gate-valve with a plastic handle. It's stuck and difficult to close, so it's time to replace that too. It's going to be a non-genuine replacement from YachtBoatParts UK, with a 90 degree elbow fitting. Thanks Chris from @SailingBritaly for the tip! We decided to keep the existing plumbing layout and just replace the fittings and hoses with brand new. Drawings are helpful to see clearly which parts needs to be ordered. Here is the plan:


The toilet layout is rather unusual and was already like this, but it seemed to work so we will stick with it. With the T-piece and two ball valves it's possible to direct the waste towards the tank or overboard right at the toilet. The same hose and outlet can be used for draining the tank overboard if needed. The Y valve at the tank selects the direction between the deck pump-out or sending it overboard.


There is some unusualness in the galley too. The bilge pump connects to the siphon of the sink with a loop above the waterline and drains overboard in the sink water outlet. I think it's a good solution as the sink drain is quite large and there is no need for drilling one more hole. I plan to upgrade the bilge pump though. There is a separate hose for the manual bilge pump that exits above the water line. Hopefully the weather will stay warm enough to use the sealants, so the job can be completed before the winter.
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