Flat-head flat-bottomed internal water sailboats do not require ballast. The sides are usually straight and the hull appears relatively flat. This causes their roll righting torque to be similar to that of a catamaran: a small inclination angle can provide a large initial angle. Stabilize the torque. In this case, even if ballast is installed on the bottom of the bilge, it is of little use. Another reason is that the wind in the internal water is relatively small, so there is no need to worry about the ship being blown over.
If you intend to use this type of ship at sea, you should deepen the hull draft and increase the freeboard height, and increase the ballast. Traditionally, ballast is usually rocks on the bottom of the ship (fixed with some cement-like glue). Chinese sailing boats do not place ballast outside the hull (such as fin keel), but there are temporary ballasts to deal with storms: some cages filled with rocks are lowered from the side with ropes, which can increase the resistance to storms. ability. We must realize that this is just a way to deal with storms, not as a structure of a boat.
Cargo ships usually fix heavy cargo in the silo to achieve ballast without reducing the cargo load.
Some wooden fishing boats in modern China still use the ancient ballast method, but the improvement is to pour concrete into the bottom of the boat. A large number of steel fishing boats do the same. This ballast method is very cheap, only a few tenths of the price of lead ballast, and does not require heating. In addition, the strength of the bottom of the ship is greatly enhanced by pouring concrete. The cost is only a few centimeters higher than the lead and the cabin height will be lowered by a few centimeters. These are completely acceptable.
Because of the flat and wide bottom of these boats, only a thin ballast thickness is required to obtain a sufficiently large ballast weight.
In terms of books, I don't have anything to recommend. There are very few books in this area. Many foreign books are about sail rig, but very little about hulls. They collected a lot of information about the shape of the JUNK, but it didn't help us much. I think the real objects and drawings can provide more help.
A traditional flat-head flat-bottomed inner water hull is like this. This ship is about 5 meters long, you can zoom in and out proportionally. The boat is made of galvanized steel, but the line type is the same as the traditional wooden boat.
It may be a little bit difficult to make this shape with plywood. Because plywood is more difficult to make bow and stern bottom bends, unless you use very thin plywood to finish it in multiple layers.
There is a sealed cabin at the bow and stern, which can ensure that the boat will not sink even if it capsizes. Traditional wooden boats also look like they are on the outside, but they are not hermetically sealed. This change may be made in the 1970s when a large number of ferro-cement boats appeared in China. In order to ensure safety, sealed cabins were made. Then this design was continued.
The way they are floating on the water. You can notice that this is a boat with outboard engines. Oh, there are almost no sailboats in China now.
This boat is actually very close in shape, that is, the place where the bow and the bottom of the boat meet need to be rounded.
A few years ago, I designed a narrow boat with a Chinese hull that could be used to navigate the narrow British canals. This is just a sketch, but it is a more accurate representation of the shape of the hull, with only a slight change: the bow is more upright on the waterline, which is a change to shorten the length of the hull.
I put this drawing here and you can use it. I don't know what version of the software you are using, so I exported it to the earlier Rhino 4.0. hope it is of help to you.
