diff --git a/controller/common/constants.py b/controller/common/constants.py
index 3dc5c4f..4a32289 100644
--- a/controller/common/constants.py
+++ b/controller/common/constants.py
@@ -1 +1,7 @@
 """Constants used across the controller package."""
+
+# meters, trim tab chord width is not included
+CHORD_WIDTH_MAIN_SAIL = 0.23
+
+# {m^2 / s at 10degC} and air density at 1.225 {kg / m^3}
+KINEMATIC_VISCOSITY = 0.000014207
diff --git a/controller/wingsail/controllers.py b/controller/wingsail/controllers.py
new file mode 100644
index 0000000..619f174
--- /dev/null
+++ b/controller/wingsail/controllers.py
@@ -0,0 +1,76 @@
+import math
+
+from controller.common.lut import LUT
+
+
+class WingsailController:
+    """
+    The controller class for computing trim tab angles for controlling the mainsail.
+
+    Args:
+    - chord_width_main_sail (float): The chord width of the main sail.
+    - kinematic_viscosity (float): The kinematic viscosity of the fluid.
+    - lut (LUT): A lookup table containing Reynolds numbers and corresponding desired angles of
+      attack.
+    """
+
+    def __init__(self, chord_width_main_sail: float, kinematic_viscosity: float, lut: LUT):
+        self.chord_width_main_sail = chord_width_main_sail
+        self.kinematic_viscosity = kinematic_viscosity
+        self.lut: LUT = lut
+
+    def _compute_reynolds_number(self, apparent_wind_speed: float) -> float:
+        """
+        Computes the Reynolds number for the main sail.
+
+        Args:
+        - apparent_wind_speed (float): The apparent wind speed in meters per second.
+
+        Returns:
+        - reynolds_number (float): The computed Reynolds number for the main sail.
+        """
+        reynolds_number: float = (
+            apparent_wind_speed * self.chord_width_main_sail
+        ) / self.kinematic_viscosity
+        return reynolds_number
+
+    def _compute_trim_tab_angle(
+        self, reynolds_number: float, apparent_wind_direction: float
+    ) -> float:
+        """
+        Computes the trim tab angle based on Reynolds number and apparent wind direction.
+
+        Args:
+        - reynolds_number (float): The Reynolds number.
+        - apparent_wind_direction (float): The absolute bearing (true heading) of the wind.
+        Degrees, 0° means the apparent wind is blowing from the bow to the stern of the boat,
+        increase CW
+        Range: -180 < direction <= 180 for symmetry
+
+        Returns:
+        - trim_tab_angle (float): The computed trim tab angle based on the provided
+        Reynolds number and apparent wind direction.
+        """
+        desired_alpha: float = self.lut(reynolds_number)  # Using __call__ method
+        return math.copysign(desired_alpha, apparent_wind_direction)
+
+    def get_trim_tab_angle(
+        self, apparent_wind_speed: float, apparent_wind_direction: float
+    ) -> float:
+        """
+        Computes and returns the final trim tab angle.
+
+        Range: -180 < direction <= 180 for symmetry
+
+        Args:
+        - apparent_wind_speed (float): The apparent wind speed in meters per second.
+        - apparent_wind_direction (float): The apparent wind direction in degrees.
+
+        Returns:
+        - trim_tab_angle (float): The computed trim tab angle.
+        """
+        reynolds_number: float = self._compute_reynolds_number(apparent_wind_speed)
+        trim_tab_angle: float = self._compute_trim_tab_angle(
+            reynolds_number, apparent_wind_direction
+        )
+        return trim_tab_angle
diff --git a/tests/unit/wingsail/test_controllers.py b/tests/unit/wingsail/test_controllers.py
new file mode 100644
index 0000000..d2e2b65
--- /dev/null
+++ b/tests/unit/wingsail/test_controllers.py
@@ -0,0 +1,107 @@
+import numpy as np
+import pytest
+
+from controller.common.constants import CHORD_WIDTH_MAIN_SAIL, KINEMATIC_VISCOSITY
+from controller.common.lut import LUT
+from controller.wingsail.controllers import WingsailController
+
+# Define test data
+test_lut_data = np.array(
+    [[50000, 5.75], [100000, 6.75], [200000, 7], [500000, 9.25], [1000000, 10]]
+)
+test_lut = LUT(test_lut_data)
+test_chord_width = CHORD_WIDTH_MAIN_SAIL
+test_kinematic_viscosity = KINEMATIC_VISCOSITY
+
+
+class TestWingsailController:
+    """
+    Tests the functionality of the WingsailController class.
+    """
+
+    @pytest.fixture
+    def wingsail_controller(self):
+        """
+        Fixture to create an instance of WingsailController for testing.
+        """
+        return WingsailController(test_chord_width, test_kinematic_viscosity, test_lut)
+
+    @pytest.mark.parametrize(
+        "apparent_wind_speed, expected_reynolds_number",
+        [
+            (0, 0),
+            (3, 3 * CHORD_WIDTH_MAIN_SAIL / KINEMATIC_VISCOSITY),
+            (5, 5 * CHORD_WIDTH_MAIN_SAIL / KINEMATIC_VISCOSITY),
+            (10, 10 * CHORD_WIDTH_MAIN_SAIL / KINEMATIC_VISCOSITY),
+            (20, 20 * CHORD_WIDTH_MAIN_SAIL / KINEMATIC_VISCOSITY),
+        ],
+    )
+    def test_compute_reynolds_number(
+        self, wingsail_controller, apparent_wind_speed, expected_reynolds_number
+    ):
+        """
+        Tests the computation of Reynolds number.
+
+        Args:
+            wingsail_controller: Instance of WingsailController.
+        """
+        computed_reynolds_number = wingsail_controller._compute_reynolds_number(
+            apparent_wind_speed
+        )
+        assert np.isclose(computed_reynolds_number, expected_reynolds_number)
+
+    @pytest.mark.parametrize(
+        "reynolds_number, apparent_wind_direction, expected_trim_tab_angle",
+        [
+            (1250, 45.0, 5.75),
+            (15388, -90.0, -5.75),
+            (210945, 170.0, 7.0820875),
+            (824000, -120.0, -9.736),
+            (2000000, 0, 10.0),
+        ],
+    )
+    def test_compute_trim_tab_angle(
+        self,
+        wingsail_controller,
+        reynolds_number,
+        apparent_wind_direction,
+        expected_trim_tab_angle,
+    ):
+        """
+        Tests the computation of trim tab angle.
+
+        Args:
+            wingsail_controller: Instance of WingsailController.
+        """
+        computed_trim_tab_angle = wingsail_controller._compute_trim_tab_angle(
+            reynolds_number, apparent_wind_direction
+        )
+        assert np.isclose(computed_trim_tab_angle, expected_trim_tab_angle)
+
+    @pytest.mark.parametrize(
+        "apparent_wind_speed, apparent_wind_direction, expected_trim_tab_angle",
+        [
+            (10.0, 0, 6.720859435489),
+            (4.0, 90.0, 5.75),
+            (10.0, 180.0, 6.720859435489),
+            (15.0, -50.0, -6.869536144),
+            (20.0, -120.0, -6.99271485887),
+        ],
+    )
+    def test_get_trim_tab_angle(
+        self,
+        wingsail_controller,
+        apparent_wind_speed,
+        apparent_wind_direction,
+        expected_trim_tab_angle,
+    ):
+        """
+        Tests the computation of final trim tab angle.
+
+        Args:
+            wingsail_controller: Instance of WingsailController.
+        """
+        computed_trim_tab_angle = wingsail_controller.get_trim_tab_angle(
+            apparent_wind_speed, apparent_wind_direction
+        )
+        assert np.isclose(computed_trim_tab_angle, expected_trim_tab_angle)