The plan for the rudder sink weight has become just a little bit more complicated than I expected. I have some steel bar that I can use to make the two weights but this has number of problems that make using steel bar impractical. The first is that the size of the required bar, even in two parts, is too big. The second is that the rudder blade is not flat but curved and thick steel bar is difficult to bend to conform to the curvature. The third is that steel bar on the blade is going to make the rudder less effective due to turbulence. The fourth is that steel rusts and even with a protective coating rust is going to form. The fifth is that chunky great steel bars on the blade is bound to snag when sailing. All in all, steel bar was discarded as a means for weighting the blade.
Instead I decided to use some lead. After all, I have plenty of it. This is where it started getting complicated. The lead would have to be melted and cast into a suitable shape. That being the case it seemed to be reasonable to make that shape as hydrodynamic as possible. To cast lead you need to have a suitable mould and although you can use wood, it chars easily and if the lead is too hot, it burns.
That leaves proper casting sand which is easy to get hold of and for melting the lead I can either use the forge or the gas stove. An empty tin can will do for a heating pot but I'll need something to make the correct shape. I decided that the weight should be round and domed. Think of a round disc that has one surface shaped so that the edges are thinner than the centre.
The only thing that I have that is even close to being suitable is the cast iron lid to a small dutch oven that I have, but it is marred by having a handle.
So,I shall try to use a piece of plywood.
It's difficult to explain how I intend to do this, but will be much easier to show it is use. I'll photograph the process and we shall see what happens.
The weights will be bolted to the blade necessitating two holes in the blade and these will be drilled over-size, filled with epoxy and the epoxy drilled to the correct size so that the edges of the wood of the blade are not exposed to water.
Should be a nice project.
But I think you see what I mean by "getting complicated".
Incredibly, I have owned Naiad for six years as of today (Monday). Time to look back and reflection what I have done.
This last year, for fairly obvious reasons, has been pretty dire in terms of sailing but in terms of owning Naiad, I am just as pleased to own her as before. Over the past 17 months I have worked on Naiad and all that is left to do is to repair the slight ding in the forefoot where I banged her on the trailer getting her out of the waterless year, to paint the coachroof, deck and topsides, dress the spars and finish the sink weight on the rudder blade. Then she will be ready to go back in the water.
One task that also needs to be done is to make a trailer guide so that when she is next taken out of the water, the guide will assist in locating her on the trailer. Not having this doesn't stop her from going back in the water, but I will make life difficult when she next comes out if I use a slipway.
There are only four weeks left before our Broads holiday so I will aim to get her ready to go back in the water after we return from that. Trying to get her in before then is going to be difficult given all the other things that occupy our time.
Frankly, I can't wait to get her sailing again despite the geographical difficulties in this area. I will consider putting her on the Boards for a few months next year, I think, just to get some open water sailing done, I may even investigate doing this every year. This river sailing is all very well but the high banks make it less than ideal and I really wish to be able to sail her on open water for a change.
One of the things that I find irritating when sailing Naiad is her rudder. It works fine and looks good, but getting it down is a pain as the blade is so buoyant. Now, the standard way to deal with this is to weight the rudder blade so that it is either neutrally buoyant or negatively buoyant. In the first case the rudder blade does not sink or float in the water whereas in the second case the rudder blade sinks.
The negatively buoyant rudder blade tends to be used for self-setting rudders in waters where the rudder is in danger of snagging in shallow water. If, for example, the boat sails close to a sandbank, the the rudder pivots up as it slides over the sandbank and when the boat is back in shallow water, the blade sinks back down to the working position. For this to work, the blade is often made quite a lot heavier than water so there is always sufficient force downwards to set the rudder blade.
In the first case, that of neutral buoyancy, the rudder is raised and lowered by means of lines but the lines are not cleated or tied off so that if the rudder snags, it can lift. Then, when back in deeper water, the downhaul line is used to lower the rudder blade back down.
It is the second of these that I want for Naiad. The rudder is currently so buoyant that I cannot lower it using the downhaul and have to use the paddle to push it down and this is the bit that is really irritating. If the rudder snags and lifts for any reason whilst we are sailing, it is a right pain in the neck to use the paddle to lower the blade whist still moving.
So, the new task is to add a sink-weight to Naiad's rudder blade so that the blade may be easily raised and lowered using the up and down hauls.
Now it the right time to do this since the next task on my list is to sand and paint the rudder blade and stock, so adding a sink-weight should be done before that.
But how much weight should be used?
One method is to put the boat into the water and mount the rudder. Then weights are tied to the rudder until the desired buoyancy is achieved. The rudder can be dismounted, brought back to the workshop and the correct weight mounted permanently on the blade.
However, that is not the way I am going to do this. Instead I shall remove the rudder blade and take it to the water trough in the field that the horses use for drinking water and put the blade in the water. I can then add weights on the blade until it just sinks. Or, even better, I can use a digital luggage scale and a stick to push the rudder under the water and the reading on the scale will shown me exactly what weight is required.
Having sorted that out I then need to decide how to fix the weight to the blade. There are three main ways to do this. The first is to encapsulate the weight inside the blade. You'd do this if you were making the rudder blade from scratch. The second method is to cut a hole in the lower part of the blade the same shape as the weight and fix it in the hole. You can also melt lead and pour it into the hole. The third was is to bolt the weight on the outside of the blade and this will be the method I'll use, at least initially. I shall divide the weight in two and bolt the weights to the lower part of the blade with bolts passing through the weights and the blade.
The reason for using this method is that I can experiment with different weights by adding or subtracting metal during the season to achieve the best result for this rudder. I don't want it so weighted at the tip that the up haul cannot pull the blade up. Once I have the weight set correctly, I can set the weight into the blade permanently the next time Naiad is out of the water.
The rudder blade didn't quite fit into the water trough but it did float once the trough was filled up a bit more. The scale read 480g (17 oz) of weight required to sink the blade, but this is only is only very approximate due to the lack of space in the trough. The solution is to take the rudder blade down to the mooring with a number of weights, I used all my spanners and two vice grips, put them into a net bag and tied that to the blade. Then put the blade into deep water and see what happens. With a rope tied to the blade, of course.
The river test shows that 1.68 kg (59 oz) just allows the blade to float and 2.25 kg (79 oz) allows it to just sink. This also shows that there wan't enough water in the trough for the first test to work.
So, I shall just an initial weight of 1.5 kg (53 oz) including the bolts holding the weights to the blade and see how that works when Naiad is back in the water.
Today's task was to complete the repair for the traveller. With most of the work completed yesterday I didn't expect this to take too long, so I carried out a couple of other small tasks as well since I have the time.
The first thing to do was to coat the other side of the pads with epoxy and fill the screw holes. Here you can see the pads over the Rayburn in order to make the epoxy cure faster.
Whilst the epoxy was curing I lifted the spars back up in the hat barn. During the application of the last coat of varnish, the fourth as I recall, I noticed that some parts of the varnish were showing a tendency to creep, so I decided that this was the last coat for this season and now the spars are hanging up out of the ways to allow access to the bay and to allow the varnish to harden.
They rusty ends of the traveller were coated with rust converter and here you can see the converter at work turning any rust to a purple colour.
Butyl tape was put around the stops on the horse...
...and on the lower side of the upper pads.
The pads were then pressed lightly onto the after deck, the traveller mounted in the holes and the washer and nut, and the new starboard pad, were fixed on the underside and gradually tightened up.
The idea is to apply some pressure to the butyl tape so that it spreads out thinly filling the gaps but not too tight so as to crack the wooden pads.
The tape under the pad hasn't quite squeezed out in one place just yet, but give it a few hours and it will. Then the nuts will be tightened up a little more and left a while and this repeated until a really good seal is achieved. However, you don't want to go too far and squeeze all the tape out of the joint. when the nuts are tight enough I'll remove the excess tape and return it to the workshop as it can be used for something else.
The finish on the spars is remarkably good considering that the varnish was applied in less than ideal circumstances.
There are one or two dead insects in the varnish and a few drips, but nothing that is a concern.
Another task on the list was continued, that of washing the ropes. It is usual to wash the ropes at least once a season when sailing on the sea since the salt water gets into the ropes and evaporates leaving salt crystals behind which are surprisingly sharp. This damages the ropes from the inside if they are used too much when salty, so the ropes are regular washed in fresh water to remove the salt.
It's not so necessary when sailing in fresh water, but it is still a good idea anyway. The trick is to wash the ropes loosely coiled and placed into a laundry bag and to ensure that the washing machine is set with no spin. Heavy ropes like these can really unbalance the machine if it spins, so it is best to turn this off.
It is also needful to ensure that the washing machine is not overloaded. Ours has a maximum laundry weight of 8kg and you'd be surprised at just how few ropes that turns out to be.
Once the ropes have been washed they are taken out of the bag, recoiled and placed on a drying rack to drain and then dry. Here I have the last four wash loads of ropes drying. These were done a few days ago and are still a little damp as the weather hasn't been that warm. The next few days should sort that out as the forecast is for between 16 and 20 Celsius over the next three days.
Summer has come early for 2021. Make the most of it, by Wednesday we're back to Winter until next year.
Time for a fresh cup of tea.
The main task for today is to repair the mainsheet horse, or traveller. The backing pads have started to delaminate, as I mentioned in a previous post, and need to be replaced.
The first thing to do is to remove the horse itself.
This should be a simple job since, as you can see from the photo, the nut is still in good condition despite the water ingress.
I simply unscrewed the nut until it reached the end of the horse both sides and then used a lump hammer to gently tap on the nut and the end of the metal horse. The horse came out without any difficulty. This photo shows the top half of the upper pad separating form the lower half as the horse is lifted.
This is the starboard side, notice how half of the pad has stayed on the horse and half has stayed on the deck.
Likewise for the port side. Notice that on the starboard side the thread shows signs of rusting whereas the port side does not. This indicates that whilst the water did get inside the boat through the delaminated pad and down through the hole in the deck on the starboard side, it did not get this far on the port side.
Here is a photo of the pad on the underside of the starboard side clearing showing the water damage. The port side is undamaged.
The rust on the thread isn't too bad, I'l use a wire brush to remove any loose rust and then either just liberally coat it in grease or see if I have any rust converter left that chemically changes Iron Oxide (rust) to Iron Phosphate or something like that and use that first.
Here I have three new pads cut from marine plywood the same dimensions as the old ones.
Two if these were screwed together and then run over a round-over router bit on the router table. The two needed to be screwed together as individually they are too thin for the router bit to work.
So these are the new pads almost ready for installation.
First, however, I need to remove the remains of the old pads. Now I made a mistake when I installed the original ones as I epoxied them to the deck. This meant that I needed to use my nice sharp chisels to remove the pads and epoxy.
This photo is of the port side pad partially removed and you see that the water did not penetrate as far as the hole. The black areas show how far the water penetrated.
Careful inspection of the hole through the deck shows that I did coat this in epoxy before mounting the horse, so although water has destroyed both the inner and outer pads, it has not damaged the deck since the exposed wood through the hole was sealed. I can only surmise that I omitted this epoxy coating on the pads before mounting them.
Once the pads were removed I gave them a light sanding in preparation for the next phase.
I wasn't too aggressive with the chisel so there is a little wood left form the pad still on the deck, but I don't think this will be a problem.
The pad of the underside of the starboard side was also removed with a chisel. This was a bit more difficult to achieve since I had to reach under the deck with both hands and use the chisel and mallet with my head over the afterdeck working blind. Still, with care I managed to remove the pad without and damage to the deck or my fingers.
One face of each pad and the sides were then coated with un-thickened epoxy and left or cure.
The cleaned up pads on the after deck were also coated with epoxy as was the underside pad.
However, the new pads will not be epoxied in place as were the originals, instead I shall seal the joint with a sealant. If the pads delaminate agin in the future I shall not have such a task to remove the pads as I have this time.
Of course, doing it this way pretty much ensures that this won't happen again, but if it does I am prepared.
That's as far as I can get for today. Later this afternoon I will apply another coat of varnish to the spars and continue work on the mainsheet horse tomorrow with more epoxy work.
Time for a fresh cup of tea.