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About iurie

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  1. I do not expect the batteries to be charged at anchor at all, but either during boat transfer (decrease in boat speed is expected) or during long regatta (day and night) when the batteries need to be charged without using propeller. Otherwise batteries are charged at shore. Proposed engine Volvo Penta D1-30 with 130S sail drive Proposed alternator: Mastervolt alfa 12/130 (48612130) Batteries to be charged 2 or 3 Mastervolt MLI 12/2750 Any considerations?
  2. That's a good hint. Would be nice to put an ”oh sheet 50%” and ”oh big sheet” label on top of the two switches .
  3. @Zonker I think that in between the two curves is the power that is spent in the saildrive 130S due to friction and the efficiency of transformation between rotation of the propeller and the movement of the boat. Higher the RPM -> higher the efficiency. But maybe I'm wrong. I compare with a car. If a car has a small engine I can travel with 150 km/h maximum speed. But if I turn on the Air conditioning I am able to travel with a maximum of 130 km/h. However if the car has a big engine, I can travel with 200 km/h with or without air conditioning as it does not count at all. I am nev
  4. That's why I asked. Thank you for clarification. However is still not clear how to use the prop & engine curves by adding also the the alternator, but is good to know that even a 7500 kg catamaran could have an engine of 27 HP. Engine is not for speed, but I want to be sure that is safe enough during storm and that also the batteries can be charged (faster or slower, it is not important)
  5. That's a good point. Thank you for clarification. It means that actually the electrical system should be monitored before and during storm. I am thinking in acquiring: Category Brand Item p/n Details Main battery Mastervolt MLI 12/5500 66012750 2 batteries x 27kg
  6. So I just understand that is is just a meter of more fuel consumption actually and the alternator will charge the batteries on a longer time. Sorry for these questions but I am not familiar with LiFePo batteries systems, so I am on the learning curve.
  7. I agree that 40 feet boat could be at 4.5 tons. However there is a big difference between 40 and 44 boats.As someone already mentioned on this thread the difference it with cubic factor, not just linear.So it is not just 10%. As an example Swan 42 that is competing at ORC has approx 7 tones. So a 44 fiber glass boat at 7.5 tones will be actually not heavy at all. Probably I forgot to mention that the boat is fiber glass, not carbon.
  8. I computed with Gori propeller calculator and there are warnings Of course I am not expecting to achieve hull speed by motoring, but this is computed by the software, I have no choice to change it: https://gori-propeller.com/en/calculate-propeller/ Waterline Length (feet): 44 Beam: 14 Draft: 9.1 Displacement (tons): 7.5 Displacement w/full tanks (tons): 7,55 Estimated Hull Speed: 8,89 Suggested Minimum Engine Horsepower: 30 Number of Engines: 1 Engine Details Manufacturer: Volvo Penta Engine: D1-30 Max. Horsepower: 28,4
  9. I did not said that it should be operated at 2200 RPM, but I said that if the batteries will be charging, then the alternator will consume something around 4-5 HP (which I understand is not fully correct and can be regulated trough alfa pro III regulator). I just assume that if the batteries are discharged (80%) than they should be charged and if they will be charged normally than it will be a drop of 4-5HP. This means that if the engine will be running at 3000 rpm, then the power will be 27-4=23 HP, that correspond to the engine running at 2200 rpm, for which the power at propeller will be
  10. Here it is the info from 2017: https://www.cruisersforum.com/forums/f136/volvo-penta-d1-30-and-d2-40-engine-recall-188024.html Here is information for the new D2-40 being EPA tier 3 compliant (sold 2017-2018 - http://verdemotors.ro/fisiere/RepoweringCampaign.pdf) https://www.navaboats.com/pdf/D2-40_EPATier3.pdf However this engine is not anymore found on Volvo Penta website, where its start from D2-50. https://www.volvopenta.com/marine/products/saildrive/saildrive-engine-range/d2/
  11. I really appreciate the feedback. The problem is somehow related to the fact that the choice of the engines is quite limited. By looking on the internet O understand that the cause is due to environmental directives in E and EPA regulation in the USA, so some engines that were available till few years ago, are not possible to installed on a new boat by the constructor due to this regulations. For an unknown reason, probably it can be changed, there are only two alternatives provided: Volvo Penta and Yanmar. Probably only some models of the engines can be fitted to the boat. So I made
  12. It is a 44 foot performance yacht equipped for racing. Is this drawing correct?
  13. Can a Volvo Penta D1-30 (max 28.4 HP at crankshaft) with an 130S saildrive (max 26 HP propeller shaft power) be used on a racing boat with a 7500 kg displacement, that will also have attached an Mastervolt alternator alfa 12/130 for charging Mastervolt LiFePo batteries MLI 12/5500? The alternator seems to use also about 3-4 HP (130Ax14.25V = 1,85kW = 2,5 HP) Max 26 HP at propeller would be at 3200 rpm, but in normal conditions at 2200 rpm would be 8 HP at propeller. Is that such a rule of thumb is that race boats should have 1 HP per thousand pounds of displacement? So for
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