Edit History

7.Mai.2018

Har en liten beregning under, men den er sikkert ikke helt rett da jeg ikke er helt sikker på vekt og om skroget er halvplaner.

Data Input

Waterline length in feet:	28 feet
Beam at the waterline in feet:	9 feet
Hull draft in feet (excluding keel):	3 feet
Vessel weight in pounds:	6100 lbs
Engine Horsepower:	96 HP
Number of engines:	1
Total Engine Horsepower:	96 HP

Engine R.P.M. (max):	3600 RPM
Gear Ratio:	2.6:1
Shaft R.P.M. (max):	1385 RPM

Number of shaft bearings (per shaft):	1
Desired speed in Knots:	15 knots

This will calculate the maximum horsepower and torque available at the prop(s).

Total available horsepower at the engine(s):	96 HP
Total available torque ft/lbs at the engine(s):	140 ft/lbs
Horsepower loss of 3% per gearbox:	- 2.9 HP
Horsepower loss of 1.5% per shaft bearing:	- 1.4 HP

Total horsepower available at the propeller(s):	91.7 HP
Total torque ft/lbs available at the propeller(s):	348 ft/lbs

Basic displacement speed and horsepower required
Displacement hull speed (1.34 X sqrt of waterline length):	7.09 Knots
Minimum horsepower required at propeller(s) for Hull speed:	13.3 HP

Calculations based on desired speed and available HP
HP required at propeller(s) for desired 15 knots speed:	115 HP
Estimated maximum speed with existing 96 horsepower: This is the speed we will use for the propeller size.	13.89 Knots

At this point it is important to note that all of the calculations above are based on full RPM and HP. Most engines are rated to run at a percentage of thier full RPM. This is what will determine your maximum cruising speed. The propeller sizing calculations below are based on 90% of full RPM. This gives the engine some reserve power to allow for variable loading in the vessel.

7.Mai.2018

Har en liten beregning under:

Waterline length in feet:	28 feet
Beam at the waterline in feet:	9 feet
Hull draft in feet (excluding keel):	3 feet
Vessel weight in pounds:	6100 lbs
Engine Horsepower:	96 HP
Number of engines:	1
Total Engine Horsepower:	96 HP

Engine R.P.M. (max):	3600 RPM
Gear Ratio:	2.6:1
Shaft R.P.M. (max):	1385 RPM

Number of shaft bearings (per shaft):	1
Desired speed in Knots:	15 knots

This will calculate the maximum horsepower and torque available at the prop(s).

Total available horsepower at the engine(s):	96 HP
Total available torque ft/lbs at the engine(s):	140 ft/lbs
Horsepower loss of 3% per gearbox:	- 2.9 HP
Horsepower loss of 1.5% per shaft bearing:	- 1.4 HP

Total horsepower available at the propeller(s):	91.7 HP
Total torque ft/lbs available at the propeller(s):	348 ft/lbs

Basic displacement speed and horsepower required
Displacement hull speed (1.34 X sqrt of waterline length):	7.09 Knots
Minimum horsepower required at propeller(s) for Hull speed:	13.3 HP

Calculations based on desired speed and available HP
HP required at propeller(s) for desired 15 knots speed:	115 HP
Estimated maximum speed with existing 96 horsepower: This is the speed we will use for the propeller size.	13.89 Knots

At this point it is important to note that all of the calculations above are based on full RPM and HP. Most engines are rated to run at a percentage of thier full RPM. This is what will determine your maximum cruising speed. The propeller sizing calculations below are based on 90% of full RPM. This gives the engine some reserve power to allow for variable loading in the vessel.

7.Mai.2018

Har en liten beregning under:

Waterline length in feet:	28 feet
Beam at the waterline in feet:	9 feet
Hull draft in feet (excluding keel):	3 feet
Vessel weight in pounds:	6100 lbs
Engine Horsepower:	96 HP
Number of engines:	1
Total Engine Horsepower:	96 HP

Engine R.P.M. (max):	3600 RPM
Gear Ratio:	2.6:1
Shaft R.P.M. (max):	1385 RPM

Number of shaft bearings (per shaft):	1
Desired speed in Knots:	15 knots

This will calculate the maximum horsepower and torque available at the prop(s).

Total available horsepower at the engine(s):	96 HP
Total available torque ft/lbs at the engine(s):	140 ft/lbs
Horsepower loss of 3% per gearbox:	- 2.9 HP
Horsepower loss of 1.5% per shaft bearing:	- 1.4 HP

Total horsepower available at the propeller(s):	91.7 HP
Total torque ft/lbs available at the propeller(s):	348 ft/lbs

Basic displacement speed and horsepower required
Displacement hull speed (1.34 X sqrt of waterline length):	7.09 Knots
Minimum horsepower required at propeller(s) for Hull speed:	13.3 HP

Calculations based on desired speed and available HP
HP required at propeller(s) for desired 15 knots speed:	115 HP
Estimated maximum speed with existing 96 horsepower: This is the speed we will use for the propeller size.	13.89 Knots

At this point it is important to note that all of the calculations above are based on full RPM and HP. Most engines are rated to run at a percentage of thier full RPM. This is what will determine your maximum cruising speed. The propeller sizing calculations below are based on 90% of full RPM. This gives the engine some reserve power to allow for variable loading in the vessel.