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# Freeware Propeller Calculator - Chelsea Coach Works - engine displacement calculator

PropCalcPlus Propeller Calculator
Enter your data in the blue boxes below.
Computed values will display in the yellow boxes.
BHP 325 (1)
Max RPM 5600 (2)
Peak Torque 230 ft-lbs 32 kg-m (3) Not used
Peak Torque RPM 4800 (4) Not used
Gear ratio 1 (5)
Displacement 2400 lbs 1089 kg (6)
Waterline length 16 feet (7)
Desired cruise 25 knots 29 MPH (8)
Desired max speed 40 knots 46 MPH (9)
325 Engine Horsepower
5600 Engine R.P.M. (max)
305 Engine Torque ft/lb
315 SHP - Shaft Horsepower at gearbox output
1 Number of bearings between gearbox output and propeller
1.00 Gearbox reduction ratio
1.50% Percentage power loss due to shaft bearings.
315 Shaft Horsepower at propeller.
5600 Propeller RPM
296 Propeller Torque ft/lb
Summary
54.4 Approx maximum speed attainable (knots) 63 MPH
315 Shaft Horsepower available at propeller
171 Shaft HP required to attain required speed of 40 knots
13 Required pitch for top speed
Propeller diameter (inches) 11 Pitch 13 (10)
Max speed diameter (inches) 10 Pitch 15 (11)
See Power Required and 3 Bladed Prop worksheets for more details.
Approximate Speed
Propeller pitch 13 Enter value for propeller pitch (See Lines 10 & 11) (12)
Gear Ratio 1
Shaft Teoretical 10%
RPM RPM MPH Slip
1000 1000 12.31 11
2000 2000 24.62 22
3000 3000 36.93 33
4000 4000 49.24 44
5000 5000 61.55 55
6000 6000 73.86 66
See Speed Table worksheet for more details.
Crouch's Planing Speed Formula
Kts = C / (LB/SHP)0.5
Where :
Kts = Speed in knots = Boat speed, V
C = Constant chosen for the type of vessel being considered
LB = Displacement in pounds
SHP = Horsepower at the propeller shaft. SHP = ( BHP * 0.97 ) * ( 100 - (0.015 * number of bearings) / 100)
Kts = C / ( LB / SHP ) 0.5
= 150 / ( 2400 / 315 ) 0.5
= 150 / ( 7.614147673 ) 0.5
= 150 / 2.759374508
= 54.3601456
= 55 Knots ( 63 MPH )
Spreadsheet prepared by Pauk Kane, Kane Custom Boats Ltd., Chelsea, Quebec 08 Apr 2013 14:27
Building the Glen-L Hot Rod : http://www.KaneCustomBoats.com
This will calculate the Displacement Speed Formula for the hull.
Speed:Length Ratio up to 1.6=displacement, from 1.6 to 2.8=semi-displacement, over 2.8=planing.
2,400 Maximum Displacement of vessel in pounds.
16 Waterline Length of vessel in feet.
40 Required maximum speed in knots.
10.000 Speed:Length Ratio.
Suggested max practical displacement hull speed for LWL input ---> 6.00 Knots
315 Shaft Horsepower available at propeller from "Torque & Shaft Horsepower" sheet
8 Pounds per Shaft Horsepower available (power/weight ratio)
1978 Shaft Horsepower required at propeller
1 Pounds per shaft horsepower required.
For planing hulls , where C= 150 for runabout, 190 for fast, 210 for race.
150 Enter "C" for your hull.
54.4 Approx maximum speed attainable with motor data from "Torque & Shaft HP" sheet.
171 Shaft HP required for speed required at top of page.

What is engine displacement and how is It measured? How is CID calculated? c.i.d. = 0.7854 x Bore2 (in.) x Stroke (in.) x Number of Cylinders. cc = (0.7854 x Bore2 (mm) x Stroke (mm) x Number of Cylinders) Ă· 1,000. 0.7854 x 3.7802 x 3.622 x 8 = 325 c.i.d. (0.7854 x 962 x 92 x 8) Ă· 1,000 = 5,327cc.

#### Pdf INFO

Title: Freeware Propeller Calculator
Subject: Marine Engineering
Author: J Bunt
Creator: Microsoft® Office Excel® 2007
Producer: Microsoft® Office Excel® 2007
CreationDate: Wed Apr 10 12:10:59 2013
ModDate: Wed Apr 10 12:10:59 2013
Tagged: yes
Form: none
Pages: 11
Encrypted: no
Page size: 612 x 792 pts (letter) (rotated 0 degrees)
File size: 579005 bytes
Optimized: no