# Calculations for designing a propeller?

Discussion in 'Propulsion' started by Bharat Kandpal, May 1, 2020.

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1. Joined: May 2020
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Location: India

### Bharat KandpalNew Member

Good Evening.
I am having problem deciding the specifications of my propeller, I have already obtained the curves for Resistance and Power vs speed.

My ship has a Length of 91m, beam of 10.5m and a Draught of 4.5m.
It is presently run using a 5 bladed 2.8m dia two in number propeller and with a engine capacity of 7200Hp connected to each shaft. The length of shaft line is 18.77m.

I aim to replace the engine with a motor, the work for which is already in progress.
The problem comes with the propeller as the Propeller was a N series propeller of which I have no data available.

Request any help on this.

2. Joined: Aug 2002
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Location: Milwaukee, WI

### gonzoSenior Member

An engine and a motor are the same thing. Can you explain what the change is?

3. Joined: May 2020
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Location: India

### Bharat KandpalNew Member

I have varying requirement as far as my engine goes and the control parameters for a motor are completely different.
I require the Torque characteristics of both motor and propeller to match them thereby I have to start from zero.

4. Joined: Aug 2002
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Location: Milwaukee, WI

### gonzoSenior Member

In English engine and motor are synonyms. I don't understand what you are talking about as if they are different. Can you explain what you call an engine and a motor?

5. Joined: May 2020
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### Bharat KandpalNew Member

Oh sorry my bad, when talking of an engine I was talking of a 18PA6V280MPC , Internal combustion engine, that runs on diesel as fuel.

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Location: Milwaukee, WI

### gonzoSenior Member

What do you call a motor?

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