Re: Resistance calculation

DELFTship forum Hydrostatics and stability Resistance calculation Re: Resistance calculation


Well, you can always try to turn your boat 180 degrees around. The algorithms used however are based upon a specific type of ship. You cannot used the Delft series, which is based upon sailing yachts, to predict resistance for planing motr boats for example. And of course the methods are also based on ships sailing with the pointy end in front;)

In short, it’s possible to fool the software by rotating your vessel, but the results will be useless.

Hmmm… That raises a question.

I had not until recently and then not again until reading this realized that calculations are (in my mind, crippled) in that someone, somewhere, deciced that Naval Architecture shall measure from the right, pointy end on the right, and that “tradition” flowed henceforth through time.

Given the computer age, I personally, strongly feel that modeling software in any industry should ask the user the USER’s prefered model orgin and then calculate from there. One Nav Arch I asked a couple of years ago had no specific on why it is that way, but posited that rudders were drawn first and therefore the architect or drafter started from the left and rolled the drawing scrolls up from the left.

Regretfully (wryly/snidely), I learned to draw ships (space ships) from the left to right, bow to the left, sine it seemed logical to them that since we typically use rulers and measuring aids numbered lowest at left, the art would follow function. Some real-world naval architects follow suit, but “tradition” has crept its head into the computer world and I suppose there is “resistance” to most firms providing calcs that work with the USER orientation, not implacable tradition.

So, now, I that while I could (and did) rotate my models 180, because my paper drawings are that way and because transferring information would be less insane, all the resistance calcs are worthless (not just because my hull is far, far larger than yachts, and later it finally was strongly impressed upon me that Delft series results are not applicable to frigate-type hulls), or rather, meaningless. (This makes me wonder and tempted to rotate the model again, bow to right, and running calcs on both. I thought I had checked just before committing myself to doing so, back in 08, but now I cannot recall, hehehhe…)

Thing is is that I don’t recall the manual stating the bow must be on the right. The calcs didn’t display a preamble of such a requirement, either. However, I am not a Naval Architect, and naturally would not expect to be constrained by programming or tradition. I generally thought it was something traditional, not that it was convenient for titleblocks to be read easier.