Propeller Nuts

The propeller fits onto the tapered shaft tip and is tightened into place by two nuts that thread onto the end of the propeller shaft. One nut is small, the other nut is big. This brings up the question of which order should the nuts be placed?

You could either place the big one on first, tighten it all the way, and then place and tighten the smaller one. Or you could place the smaller one first and tighten it all the way, and then place and tighten the bigger one. So many options on such a tiny part of the boat that is instantly forgotten the moment the boat goes into the water.

The proper order is the small nut first and the big nut second.

When you tighten the small nut against the propeller, the force of the propeller is then pushed onto the threads of the nut and shaft. When you tighten the big nut, the lateral pressure from the small nut is transferred to the big nut which has more threads and transmits the force more evenly to the threads of the shaft tip.

The reason to have two nuts is simple, when they are tightened against each other, they will apply lateral pressure away from each other and seize to the threads that they are pushing against. When the two nuts are tightened into each other, they will not come loose as the entire assembly spins furiously without any inspection. As a safety precaution, the end of the shaft will have a cotter pin just in case the nuts come loose. A loose propeller is a problem that can quickly be remedied. A lost propeller is an expensive problem that is not easy to fix when out at sea!

Next time you are on the hard, take a look at the nuts at the end of the propeller shaft and make sure that the small one is next to the propeller, followed by the big one. 

Cutting Planks Around a Knot

When resawing lumber to make planking stock, you have a few goals in mind:

• You want to create clear planks with no flaws or knots
• You want to convert as much wood into planks
• You want to minimize waste

When you buy a massive 2x12, there will be flaws scattered throughout the piece. This is the price you pay when the price you are paying is low. If you opt to splurg, you can easily purchase perfect clear grain wood for an astronomical fee. If you are budget conscious, you will find yourself picking up your Douglass Fir at Home Depot or Lowes, where a 16 foot board only costs $25!

This flatsawn board has a few checks and a few knots, but the majority of the board is clear with very tight rings. Ripping the board into three will yeild one flatsawn section and two quarter sawn sections with tight and close annual rings.

After the board was ripped and cut, it was time to resaw the smaller boards to create the 1/4 inch thick planking stock for the dinghy. It is easy to discard boards that have major flaws such as knots or checks, but this would be wasteful. Yes, a flaw will always be a flaw, but it can be worked around!

Remember, when planking the hull, there is always a section of the plank that overhangs and will be cut off. If the flaw is towards an end, placing it in the cutoff section will make the flaw disappear while making that plank usable!

What if the flaw is smack in the center of the board? Is that whole piece lost? Nonsense! We just need to work around that problem to extract as much usable wood as we can.

This gorgeous quarter sawn board had a big old knot right in the middle! To get as much clear stock out of this board as I could, I selectively resawed this board, carefully taking planks out of the board without involving the knot.

The top cut moves the knot over a bit, allowing the bandsaw blade to glide by in clear wood. This means that the first plank will be full height while no involving the only flaw in the board.

The process of cutting the top off to expose more clear wood on the side continues as you move across the board. The result is similar to the cut pattern when a log is quartersawn, where you form an alternating step pattern in the boards. The planks aligned vertically are all the planks that I was able to extract from this board without any sign of the flaw while the planks aligned horizontally are the scrap pieces that include the flaw.

Here, the board is reassembled, showing all the cut wood that came from it. You can see the off cuts that are flawed or not fair as they rest on top or on the side of the stack.

The good planking material extracted from this board will serve us very well as it is without flaws. If this board had been discarded, all of this material would have been lost! If the knotted section were to have been cut off, all the wood higher than the front plank would also have been lost. It is a bit more time consuming to orient the board in such a way as to extract as much clear wood as possible, but the cost savings are substantial and should not be overlooked.

Backstay Adjuster

Split or twin backstays offer a unique opportunity to setup a backstay adjuster: A backstay pincher.

Using three Antal frictionless rings, you can easily fabricate your own backstay adjuster that will pinch your backstays together and add the needed tension to the headstay on the otherside of the mast.

The three rings are spliced together into a Y shape with the two rings on the backstays tied together in a close shape. The third ring is used for the control line. 

Above the Y, a block was attached to the backstay which allows us to easily raise the adjuster to ease the backstay. Pulling the adjuster down, the backstay adjuster slides down the stays and pinches the two stays together which will add tension to the headstay. Frictionless rings slide easily over dyneema stays, removing the need for any mechanical advantage from a block and tackle system.

Shrink Wrap in the Spring

It's been getting warmer and warmer outside, but I'm still working on a few projects in the cockpit! It's too hot to keep the shrink wrap on but I don't really have time to take down the shrink wrap. What to do?

Windows! We cut holes in the shrink wrap that allow air to flow through the canopy in a very time efficient manner. We are still wrapped up, so I can complete my projects without fear of parts falling overboard all the while enjoying the fresh air as it flows through the cockpit.

Rainwater Plumbing: Tank to Destination

Now that the water is in your tank, how do you get it out so you can use it? 

We could hook the tank up to the regular water tanks pump, but what if something we don't like got into the rain water tank? How would we get rid of it without contaminating the rest of the tanks?

The simple idea of having a tank full of rain water quickly became a concern about damaging the rest of our water supply. The decision was made that the rain water tank needs to have a purge hose that we can drain its contents should we decide that it has become compromised. I thought about making a very complicated valving system where water from the rain tank could be tested and purged if desired without going into the main tanks or, by opening some valves, used in conjunction with the rest of the water tanks. This idea, while complicated, seemed like an adequate solution.

The only caveat with this plan has to do with the flexible water tank and its durability. Flexible water tanks are a great way to get water tankage into small nooks in the boat where a regular tank would be difficult to install or fit. The problem with flexible water tanks stems directly from this flexibility. 

As the yacht bounces around in the seas, the water inside the tank will slosh around. In a rigid tank, the contents move while the tank remains un-phased. In a flexible tank, the contents of the tank move along with the tank. This constant sloshing will wear on the seams of the tank and lead to the eventual death of the flexible water tank. It is best to use flexible water tanks only for a short period of time and then store them drained and empty while underway.

If we use the rain water tank as part of our water tanks, it will suffer greatly from constantly flexing as it is the lowest tank and would stay full the longest. The alternative is to fill the tank with rain water and drain the tank instantly into the other water tanks through a hose with its own pump.

This would satisfy all the needs we have placed upon the flexible water tank. It would allow us to test the water, purge if undesirable, and maintain the tank empty for as long as possible. We also don't have to worry about accidental contamination from the flexible tank to the other tanks because there would be no direct plumbing fitting that could be left open and cause a disaster.

The flexible tank drains via a small 1/2 inch water hose that is led to a high powered water pump. This pump will flow 4 gallons per minute at 60 psi through a hose that will allow us to test the water, and if we like it, dump it into the main tanks. If we don't like it, we can purge it overboard or use it for showering and laundry. Best of all, it keeps us actively watching where and how much the water is going into the different tanks.

The dedicated water pump was mounted under the galley sink on a bulkhead where the hose to feed the tanks could easily be stowed.

The long hose is able to reach all the tanks in the boat, even the tanks located under the V berth in the bow. The ball valve makes it easy to turn the water flow on or off to facilitate filling each tank to capacity without getting your hands in the tank. The pump can flow 4 gallons per minute at 60 psi. This would take 40 minutes to fill up all the tanks (160 gallons) at a fuel dock, but we anticipate that it will run much faster since there is no resistance in the system; hopefully decreasing the time we spend tied up to a pier as we refill our water supply.

The long hose tucks up neatly under the galley sink area, allowing us to carry this convenient length of hose without impinging on our daily life aboard.

The plumbing is complete, but we still need to power the pump. This is where my less favorite part of boat projects comes into play. As you may have noticed, I don't particularly care for electronic devices. Mechanical devices have all their parts on display while electrical devices have all their parts tucked away behind insulative barriers, hiding their corrosion and problems as you wonder why it's not working when you need it. 

Nonetheless, the water pump is electric and needs to be wired into the boats electrical system. This involves running a new positive and negative wire from the breaker panel down through all the inaccessible crevices to lead the wire to the pump. The first step is to open the panel up and start fishing wires through the backs of the interior joinery. 

While it may look like a spider web of wires, it actually isn't that confusing. All the positive (red) wires are on the left side, all the negative wires (black) are on the right side. It may be tempting to wire the negative onto another passing negative wire near the water pump, but this is not advisable. Each electrical component should have its own negative wire that runs back to a central negative buss bar.

Now that the pump is plumbed and wired, the rain water collection and distribution system can now be considered complete. All we have to do is wait for our next rain storm to give it a test!