# What is drag force for boats?

## What is drag force for boats?

Form drag is a force proportional to the square of the boat speed that depends on a drag coefficient which incorporates area of the shell and density of water. Skin friction is based on the friction between the water and the shell.

### How do you calculate hydrodynamic drag?

The hydrodynamic drag is X = cx(ρv2/2)S, where ρ is the density of the medium, v is the velocity, and S is the characteristic area for the given body.

**What is the drag coefficient of water?**

The experimental tests performed produced an estimation of the drag coefficient of the water rocket of Cd = 0.345 ± 0.004 within the Reynolds interval 103 < Re < 2×105. It was found that the magnitude of this coefficient fits reasonably well with that of an ellipsoid with a length/diameter ratio of 1.5.

**How do boats reduce drag?**

Weight Reduction and Balance. Reducing weight is a form of reducing drag. If you overload your boat with weight, you increase its displacement at lower speeds, and reduce lift at higher speeds. Removing unnecessary gear and objects is obviously the easiest way.

## What does dragging mean on a yacht?

A merchant vessel is said to be having a “dragging anchor” when the vessel drifts without holding power inspite of being anchored. Dragging anchor has been the reason for several accidents such as collision, grounding, or stranding.

### How do you calculate coefficient of lift?

The lift coefficient is defined as: CL = L/qS , where L is the lift force, S the area of the wing and q = (rU2/2) is the dynamic pressure with r the air density and U the airspeed. Similarly, the drag coefficient is written as: CD = D/qS , where D is the drag force and the other symbols have the same meaning.

**How is dragging anchor calculated?**

Swinging circle of the ship If the ship goes out of the swinging circle, the ship’s anchor is dragging. Compare this with a cow tethered to a post. The cow can only swing on a circle with radius equal to the length of the rope she is tied to. She can only go out of this circle when the rope has left the post.

**Why is it bad for an anchor to drag?**

A vessel dragging anchor is a threat to its own and also to other vessels in the vicinity, often leading to an emergency situation such as collision, grounding or stranding, depending on the manoeuvrable condition of the ship.

## What are the lift and drag coefficients?

The lift and drag coefficients, cL,D, are the rugs under which an awful lot of hard physics is swept. In practice these coefficients vary with speed and other physical attributes of the wind, and also with sail orientation Figure 4.1. (a) A fore-and-aft sail (gray) in an apparent wind velocity w%. The boat velocity is v.

### What is the drag coefficient of a ship hull?

However, for the drag coefficient of a ship hull I am confused. Page 7 of this paper shows drag coefficients for a ship hull between 0.0027 and 0.0032, while the figure on the Wikipedia page shows that for an optimally streamlined body, the coefficient is 0.04.

**What is the drag coefficient for AoA 0°?**

Note that for AoA = 0° (extreme left) drag is zero for the momentum flux curve (dashed line), since the sail is edge-on to the wind. In reality, some drag remains even for edge-on sails. Figure 4.4. (a) Lift/drag coefficients CL and CD vs. angle of attack (AoA).

**How does angle of attack affect aerodynamic lift coefficient?**

The aerodynamic data was compiled using a tool called xFoil for a Reynolds Number equal to 1 million. Increasing the angle of attack of the airfoil produces a corresponding increase in the lift coefficient up to a point (stall) before the lift coefficient begins to decrease once again.