The phrase "add fins" is correct and usable in written English.
It can be used in contexts related to design, engineering, or cooking, where fins are a relevant feature to be included or modified.
Example: "To improve the aerodynamics of the model, we need to add fins to the tail section."
Alternatives: "include fins" or "attach fins".
This is strange, because the argument that linguistic changes are just like changes in style and taste is a serious one; "there is no more reason for languages to change than there is for automobiles to add fins one year and remove them the next, for jackets to have three buttons one year and two the next" said Paul Postal in 1968.
If you don't want to add fins to your rocket, see Rocket Launcher below for design instructions.
You should add fins to your workout kit, along with the rest of your swimming toys and tools.
That modest improvement is achieved by adding fins to the condenser region of the heat pipes.
Shapers also introduced new construction techniques and materials, and added fins for stability and leg ropes to keep the surfer from losing the board.
On the whole, the formaldehyde removal performance in an annular PCO reactor can be obviously improved by adding fins to the reactor.
A significant conductivity enhancement can be achieved by adding fins, but this also leads to decrease the heat storage capacity of the accumulator by reducing the volume available for phase change materials.
In the meantime, airlines have continued to trim in search of smaller efficiency gains, charging for baggage and adding fins to the ends of airplanes' wings, for example.
Of course, the laptop equivalent of adding fins is to make them thinner and lighter than the previous generation.
They moved the center of gravity forward, put an optical sensor in the nose, and added fins to prevent the bullet from spinning — normally a stabilizing motion, but in this case it would make flight path adjustment difficult.
I remember the great days of design, the 1950s and 1960s, when we threw away the square corners and made cars longer, lower and wider, added fins, took out the center pillar between the front and rear doors and came up with the "hardtop convertible," chromed everything in sight, opened up the wheel wells and made them look fast.
