Paddleducks
General => Chat & Off Topic Stuff => Topic started by: Markds on September 20, 2013, 05:47:16 PM
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I realize this is a touch off track but, are there any magazines past or present dealing with things like how to calculate displacement, proper buoyancy, HP requirements for a specific model? I am grasping at straws but I hope you can fill me in. Thank you.
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Hi PD's......Mark....without knowing the model you are considering .......there are a few basic principals for displacement to ponder upon
1. consider a hull 1000mm long x 200mm wide and has an actual draft of 50mm
2. if this hull was a plain shoebox, 1000x200x50 = 10,000mm ...converted = 10 kg ...........& this is termed as a block coefficient
3. this means the box shaped hull will displace 10 kg to get it to the 50 mm draft level in water
4. now consider the bow & stern are not cubic blocks but are tapered
5. from here you must assume the % of taper which reduces the block coefficient
6. from here you may assume the original 10 kg [of the original box] is now reduced by that same %
A medieval sailing ship could be 80% block.........a naval cutter say 60% of block.......
I hope this helps........Derek
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Thank you Derek, you are pointing me in the right direction. I am a tool & die maker however, basic calculations and other vital things worth considering I am oblivious to. This is a new hobby for me and I have all the time in the world to learn it. I am having the time of my life with this so, you cannot dump too much on me. I am soaking it up! Anything else you want to bring to my attention you need not wait for me to ask. Perhaps in the future we will see a Beginners 101 just for newbies like myself. 8)
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A good book dealing with the topics mentioned is:
"Model Power Boats" by Edward W. Hobbs.
It is an old book which occasionally is listed on Ebay.
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Hi Mark
As I`m relativlry new to this Forum I just found your request right now. As derek mentioned before, it is important, what kind of ship you have in mind.
So here I have one link, that can help you to find out, what weight the boat will carry. Hope your german speaking is better than my english!! :16
http://www.rc-boote.at/opn/system/anypage/index.php?opnparams=A25dOVdhAmc
Greetings from Vienna
Gerhard