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Dalslandia

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About Dalslandia

  • Birthday 23/02/1959

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  • Website URL
    http://www.dalslandia.com

Profile Information

  • Gender
    Male
  • Location
    Dalsland, Sweden
  • Occupation
    Captain
  • Boat Name
    M/S Dalslandia, Olivia II
  • Boat Location
    Dalslands canal, Sweden

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  4. If I remember it correct PayPal only send out email with your name on it, and even so if they do, and something have to be changed or read, I go into the account and read it there. never klick on any links in the mail. Read about one Swed. that pranked someone that sent out a "nigerian" letter, and made an appoinment with them, and had them to buy him lunch.
  5. Saw some where, (Off T) that a narrow beam is, if it was British, EU or other standard, something like 14 or 16 feet wide, but cant remember where I saw that. Before now, a Swedish ship was longer then 12 meter and wider then 4 meter, but now if it is more then 24 meter it is a ship, not a boat. but it still say if it is a privat boat longer then 12 AND wider then 4 meter the PIC need naval licence.
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  9. correct if the efficiency would be constant, at zero speed the efficiency is zero if we see to the work of moving the boat and not the mass of water. What I meant is that there is so many variables that in practis it will not workout to give an correct number of the mass of the boat. We can also use the THP, Thrust HP instead of shaft HP*eff. THP is thrust*V, so if thrust is held constant, THP goes up with speed, or if THP is constant, thrust is going down with speed.
  10. Yes, V is speed or velocity, thrust is Power * efficiency / speed and you see that thrust is reduced with speed if Power and efficiency is held constant. efficiency is increased slightly with speed normaly untill cavitation come in. efficiency is the result of boat speed not the water. propellers have there openwater efficiency and hull its hull efficincy, with the propeller doing its job at the back. Imperial Power is a horse lifting 550 lb-ft/sec or 33000 lb-ft/min (76,04 kg-m/sec) metric horse lift 75 kg one meter in one sec. 5 hp will then make 5*75*0,5/1,8= 104 kg of thrust at 3.5 kts (4 MPH) with an efficiency of 50% thats for theory. in that case of have 50 kg of thrust at zero speed, then let go. in practise the prop will let the Engine rev more at higher speed, if perfectly governend (sp) the rpm will be held constant but fuel and Power will be reduced with higher speed due to unloaded prop, and the prop will probably have a better bite at some speed then static. to make that test correctly to get the mass of the boat, the thrust need to be monitored and held constant. Ps, I do calculate propellers for airplanes.
  11. The Thrust is not constant either, can't use static thrust to calculate dynamic thrust, and the dynamic thrust is reduced with speed, T=P*Eff/V
  12. https://en.wikipedia.org/wiki/Long_ton short ton too
  13. and ships in tons, volume that is, register ton, netto, brutto ... that is 100 cubic foot, 2.83 m^2 and feet fot and inch, lb's pint gallon ... as long as it stated what unit the numbers is in, I don't care. but you are right metric system is coming to the imperial countrys also, inch by inch.
  14. Mike, the tach suggested was a hand held optical, a mechanical will work as you suggest
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