Enter any 4 variables and the 5th variable will be calculated. Boat, Sell A However, we thinking knowing the basics behind how and why the calculator works is important, too. The Quicksilver Black Diamond is the best all around boat prop you're going to find. That equals 746 watts of energy. Re: Can you calculate boat speed from prop pitch and rpm? Accurate data is important when using this calculator. Multiply mph by 0.85 to determine final boat speed. Speed = square root of ( 50 hp/800 lb) X 150. Step up in performance with a prop thats hand finished and fine tuned from a raw stainless steel casting with perfectly matching cup heights and a custom blade thickness profile. If it is the later, then you likely have room to improve your top speed. Knowing the theoretical speed for your boat can help you select the proper pitch. Engines that have a smaller horsepower will have a higher ratio in the region of 2.33:1. Step 2: Select the Manufacturer of your Engine. Even if you never need to write it out by hand. Plumbing, Fresh Water Boat SPEED, a positive number; the boat speed in various units of measurement. The constant is applicable to a wide variety of boats, from runabouts to high-speed racing boats. This weight is usually measured in tonnes or pounds. Visit our Outboard Propeller Manufacturers and Propeller Industry Market Research Page SLIP, a percentage, 0.1 to 99.9; index of propeller performance. Boat Propeller Calculator You can use this boat propeller calculator to determine one of five variables: boat speed, propeller slip, propeller pitch, engine gear ratio, or engine revs. Calculate Slip % Get the Latest News from . Storage Systems, Lowrance Hook2-4 GPS Boat Gel Coat - Spectrum Color, Pumps and Here are a boat speed and prop slip calculator if anyone is interested: Thanks man. Enter Gear Ratio. for Sale, Buy A google_color_border = "000000"; Prop Calculator" from Continuous Wave. We offer the most-complete line of outboard power, for fishing boats and speed boats, for pontoons and tenders, for work and for play. I didn't see downeast on any of them and there wasn't an option that fit my boat either (19' fiberglass flat bottom "downeast style skiff" I guess you'd call it?). Too little is a struggle that can burn your engine. Please note: It should only be used to confirm predictions. Be aware that the factory Tachometers read 150 rpm high at 3,000 rpm. It's not too expensive, but it's built to last and to perform. Too little horsepower and you can burn your engine out far too quickly. PFDs, Roof Racks, Carriers, ! (Overall Rating: 10), Excellent high-end Pontoon Boat with a 400hp R Mercury outboard Racing motor. Insurance, Boat This one does not require as many numbers but also doesnt give you the most accurate answer. (a 15 inch pitch prop theoretically propels the boat 15 inches in one revolution). Even if you could put in accurate details, the prop calculator cannot deal with all of the unknown factors. I hope you find the calculator useful. Taking into accout the pitch, gear ratio, and using about 15% slip, I came up with 43 mph at 4500 rpm, which is about what my speedo says. Units The calculator will automatically compute the 5 th variable. Maximum "hull speed", in knots, is equal to about 1.3 X the square root of the waterline length of the hull in feet. Finding the correct propeller is as easy as 4 steps. This useful calculator computes an estimate of boat speed for a modern planing monohull using inputs of the power at the propeller shaft, the total boat weight, and a coefficient called the hull factor. The ultimate performance propeller for light-weight boats running over 75 mph. & Dock, Anchor Chains & To use the calculator, input four of the five variables. Trying to squeeze out the last bit of speed and efficiency is all about trial and error for that boat. At the very least youll want to research it further to make sure its not a problem. boatspeedcalculator.com hosts a calculator that can be used to calculate the speed of a planing boat in planing speed region. Drink Holders, http://www.rbbi.com/folders/prop/propcalc.htm, http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=009536#000000, http://www.go-fast.com/Prop_Slip_Calculator.htm. The volume is then converted to weight. You may well ask what happened to the other 8.97 MPH. Optimum Slip Percent (For max top speed), Low drive height, cabin, side by side engines, High Drives, boxes, notched transom, good bottom.