Notching the Frames

The chine log needs to be set into the frames at the turn of the bilge. This means that the corner needs to have a section cut out of it which will hold the chine log. If you a building a large craft where proper lofting was carried out, the chine log notch would have been cut when the futtocks were being cut out and assembled.  

Since we are building a small dinghy, we do not have a full set of plans and proper lofting was not carried out. The futtocks were cut out and shaped with no regards for bevels or future stringers, and simple assembled onto the keel where they await further fabrication. 

They say the beauty of building a dinghy is you can make up your mind about the finished product as you go! This statement could not be more true. You start off with a set plan in mind and then modify this plan based on materials you have access to and ease of building. 

The depth of the chine log was cut into the corner using a handsaw. Once the cuts were made, the retained wood was chiseled out in small quantities. The end result was a rather well fitting notch that will retain the chine log and tie the frames together, offering loads of rigidity to the hull of our dinghy. 

Once all the frames were notched, the chines could be test fitted to ensure that they will lay fair and flush with the curves of the hull. 

One important point that does require some forethought is the fasteners that connect the futtocks need to be set in a way that they won't interfere with the chine log. I set the lower screw more inboard and the upper screw outboard. The upper screw and lower screw were set outside the imaginary area that would become the chine notch. This allowed me to simply cut out the notch without needed to relocate any fasteners. 

When Do You Have to Shut Down the Reverse Cycle

As the temperature drops well below freezing, your reverse cycle heater will be forced to work even harder. This will keep you very comfortable while inside your yacht, but can you keep this up all winter long?

It depends on the water temperature where you are moored. The reverse cycle heater works by extracting heat from the water you are floating in, and by default, cooling the water that is pumped out the side of your boat. As the water temperature gets colder, the unit will have to work even harder to cool the water and extract all the heat available.

If the water is too cold, the unit can cause the water to freeze while inside the tubing. When the water freezes, a few things happen: The water stops flowing through the tubing; and the water in the tubing will expand.

When the water stops flowing, there is no more new water flushing through the unit and it will not be able to continue to produce heat. You will notice this when cooler air starts to flow out of the air ducts and the boat will begin to cool down.

When the water freezes, it expands. The problem is most reverse cycle units have metal tubing that does not take kindly to any expansion. Freezing water will usually crack the tubing and wreck the entire unit!

As you can see, running your reverse cycle into the winter months may sound like a good plan for heating your yacht until you factor in the limitations of the reverse cycle unit. 

A good friend of mine who installs and services marine refrigeration and air conditioners gave me some insight on the matter. He recommends shutting them down when the water temperature drops below 40F to play it safe, and an absolute minimum operating water temperature of 38F.

Excellent, now you know that when the water temperature gets below 40F, it's time to shut it down, and if you feel lucky, you can wait until the water temperature gets down to 38F before shutting it down. But how can you tell how cold the water is?

The simplest method is to pull up a bucket of water and stick a thermometer in it. This will tell you what the water temperature is right by your yacht without much involved. If you do not want to play around with buckets of water on frigid days, the other method is to look up the buoy data in your area. 

If you are in the Baltimore, MD area this winter, you can find the water temperature by clicking on the link below

All other buoys operated by NOAA can be found here, and you can search the list to find the weather station nearest your yacht. 

Keeping an eye on the water temperatures can give you plenty of warning when "shut down time" comes. The good thing about water temperatures is they don't change too quickly. If the temperature was acceptable this morning, it will be about the same this afternoon. Things that can make the water temperature fluctuate quickly are rain and snow. If you have a rain or snow storm, the water temperature where you float will change as the new water and its temperature flush out the old standing water where you are.

Shutting down your reverse cycle heater at the appropriate time this winter will keep you warm and the machinery in your boat operational for as long as possible.

Chines

Boats come in a variety of different shapes and styles, but one very simple distinction is denoted in the way the hull connects to the topsides. This area is called the "Turn of the Bilge" and can either be a soft turn or a hard corner. Soft turns are called soft chines while hard corners are called hard chines. Each has its own tendencies and characteristics.

Soft chines are easier to tip and roll around. Sailboats tend to have soft chines since they are designed to heel over and sail on one side of their hull.

Hard chines are considered more stable and are less easy to tip and roll. Powerboats tend to have hard chines as they offer more stability in a boat that is designed to stay upright all the time.

From a construction standpoint, chines offer another advantage: they offer a lot of strength and rigidity to the hull.

The chine itself is called a "chine log" and is one of the structural stringers that run the length of a craft. This stringer is the turn of the bilge and is set into the frames so that the planks can lay flush against it.

This stringer really stiffens up the frames of a wooden boat and transmits considerable amounts of load amongst the frames in the area on that side of the hull. Since the frames work more in unison, the frames can actually be spaced further apart and be made considerably smaller than if the hull had soft chines.

Less weight in frames translates into less weight overall. This is yet another reason hard chines are favored on powerboats where speed is the priority and keeping weight down is imperative.

Hard chines also make initial construction and later repairs much simpler. On a hard chine vessel, there are very few curves and the curves that are present tend to be very subtle. This means that the planks follow relatively straight paths and require very little twisting or bending to get into place. Not having to custom contour each plank means that fabrication can proceed much quicker. If you have to replace a rotten strake, fitting the new plank will also be a much easier endeavor, as it will pretty much be a straight strake that runs its length in a flat manner.

The simplicity in construction is all thanks to the chine. The topsides run down straight and meet the chine log where they end. The bottom planks run from the garboard up to the chine where they also end. There is no rounded section that needs to be fitted with scrubbed planks and corners to fair off as you try to blend a curvature into the turn of the bilge. The planks run along until they get to the corner where they simply stop and start again in a new direction without any effort on the part of the builder.

Ease of construction, ease of repair, and greater stability all make hard chine boats desirable powerboats and dinghies for your sailboats.

A Better Way to Cut Battens

One way to make battens is to rip them with a skill saw. This works quickly and will produce a nice set of battens out of a 2x4, but a lot of wood will be lost due to the blades kerf. 

A better way to rip battens is to use a blade with a a narrower kerf, as this will reduce the amount of wood that is turned into saw dust which translates into more wood that gets turned into battens.

To do this, I used a bandsaw setup with a very thin blade with a rip fence. My bandsaw doesn't have a built in rip fence, but this is easily managed by clamping a block of wood to the table at a measured distance from the blade. I chose to rip these battens to 4mm in thickness, yielding many more battens than I could have gotten with a skillsaw.

The distance to the blade is the most important point to measure, as it will determine the width of the batten. The second block was just to help me keep oriented as I was pulling the board after it had been cut on the other side of the bandsaw.

In the end, I was able to get a lot more battens out of an already used 2x4 with the bandsaw. The thicknesses were much more consistent and the waste was minimal. This resulted in more battens and less saw dust!

Tools to Build a Wooden Dinghy

Construction of a wooden dinghy only requires a few tools, some are rather specialized but the rest are general tools that any competent craftsman would have.

In the most basic sense, the tools needed are a drill, saw, wood planer, screw driver, hammer, and clamps.

These very basic tools will let you build a boat with a very basic layout and design. Any intricate cuts or features would be rather difficult to carry out. If you want to build a more sophisticated design, you will need some more sophisticated tools.

The tools I am using to build the dinghy are rather limited, as space and funds are equally limited. I am using:

• Drill Press
• Cordless Drill
• Handsaw
• Circular Saw
• Bandsaw
• Jointer
• Sledge Hammer
• Claw Hammer
• Ball Peen Hammer
• C Clamps
• Screw Driver
• No 4 Plane
• Rabbet Plane
• Jack Plane
• Low Angle Block Plane
• Block Plane
• Wood Chisels
• Rasp File
• Coarse File
• Bastard File
• Fine File
• Squares

This might seem like a rather long list, but with these tools you will be able to build a wooden dinghy with relative ease. The list provided is by no means a complete list, as there are tools I wish I had but am working without. 

A table saw would be a wonderful addition which would make partial thickness cuts easy to complete. A thickness planer would also help make the boards uniform in thickness across their length. A router would also be very useful for removing wood and reducing weight of the components in the dinghy. Lastly a bevel gauge would make it much easier to transfer angles from one area to another.

While these tools would make construction easier, they are by no means mandatory. Knowing how to use the tools you have well is more valuable than having many tools. A lot of the work can be carried out and completed with a limited armamentarium if proper experience is available to fill in the voids in missing tools.

I have seen carpenters resaw planks perfectly with a handsaw and no guides! I need a bandsaw to complete the same cut. It all depends on your skill and comfort level while working with the materials at hand.