Tractor Mode Marine Propulsion
A drive for a marine vessel may include a fully wetted propeller with a fixed drive shaft configuring the propeller in a tractor mode wherein the propeller pulls the water rearwardly relative to a bow of the marine vessel when traveling in a forward direction. The propeller is preferably mounted in a range of 10% to 60% of a length of the marine vessel toward the how from a transom and operates cavitation-free.
1 . A marine vessel comprising:
a hull including a bottom with at least one tunnel configured to accept a drive;
wherein the drive includes a fixed shaft and a tractor mode configured propeller mounted at least partially within the tunnel and configured to rotate such that a thrust is created pulling the marine vessel in a forward direction.
2 . The marine vessel of claim 1 , wherein the fixed shaft is joined to the propeller with a shaft angle of between 3-12 degrees to a horizontal plane when the marine vessel is stationary in the water, and producing an effective shaft angle of about 0 degrees when the marine vessel is in motion at a cruising running angle of attack.
3 . The marine vessel of claim 2 , wherein the shaft angle is about 6 degrees or less to the horizontal plane.
4 . The marine vessel of claim 1 , wherein the fixed shaft includes a positive shaft angle producing a lift in a bow region of the marine vessel when moving at cruising speed.
5 . The marine vessel of claim 1 , wherein the propeller is fully submerged in water and does not produce a vapor cavity when powering the marine vessel at a speed greater than 20 knots.
6 . The marine vessel of claim 5 , wherein the speed is greater than 50 knots.
7 . The marine vessel of claim 1 , wherein the propeller includes efficiency ratios of over 60%.
8 . The marine vessel of claim 1 , wherein the propeller includes a completely clean inflow condition.
9 . The marine vessel of claim 1 , wherein the propeller includes an overall propulsive coefficient of over 50%
10 . The marine vessel of claim 1 , further comprising an interceptor on a trailing edge of the tunnel providing the bow of the marine vessel with an adjustable positive and a negative lift when moving at cruising speed.
11 . The marine vessel of claim 1 , wherein when cruising at a speed greater than 20 knots, the marine vessel does not produce a roostertail.
12 . The marine vessel of claim 1 , further comprising a power source within the hull of the marine vessel mounted rearward of the propeller.
13 . A drive for a marine vessel comprising:
a fully wetted propeller when the marine vessel is floating in water;
a fixed drive shaft configuring the propeller in a tractor mode wherein the propeller pulls the water rearwardly relative to a bow of the marine vessel when traveling in a forward direction; and wherein
the propeller is mounted in a range of 10%-60% of a length of the marine vessel toward the bow from a transom.
14 . The drive for a marine vessel of claim 13 , further comprising a tunnel in a bottom of the hull, wherein at least a portion of the propeller is mounted within the tunnel.
15 . The drive for a marine vessel of claim 13 , wherein the propeller includes a diameter in the range of about 50% to 90% of a diameter of the tunnel.
16 . The drive for a marine vessel of claim 13 , wherein the propeller rotates to produce a thrust disc such that both an upper half and a lower half of the propeller produce the thrust.
17 . The drive for a marine vessel of claim 13 , wherein the propeller:
produces an effective shaft angle of 0 degrees when the marine vessel is in motion at a cruising running angle of attack; and
does not produce cavitation during operation powering the marine vessel at a speed greater than 20 knots.
18 . The drive for a marine vessel of claim 17 , wherein the speed is greater than 50 knots.
19 . The drive for a marine vessel of claim 13 , further comprising:
a v-drive unit within a hull of the marine vessel; and wherein
the drive shaft is substantially fully enclosed within the hull of the marine vessel.
20 . The drive for a marine vessel of claim 13 , further comprising:
an interceptor on a trailing edge of the tunnel providing the bow of the marine vessel with an adjustable positive and a negative lift when moving at cruising speed; and
wherein the propeller does not produce a rooster tail when the marine vessel is cruising at a speed greater than 20 knots.
21 . The drive for a marine vessel of claim 13 , further comprising:
a power source within a hull of the marine vessel and rearward of the propeller; or any position desired in the hull and
a v-drive unit within the hull of the marine vessel; and wherein
the fixed drive shaft is fully enclosed within the hull of the marine vessel.
22 . The drive for a marine vessel of claim 13 , wherein the propeller includes:
efficiency ratios of over 60%; and
an overall propulsive coefficient of over 50%.