Autohydro help

[Leron]

Hello everyone,

As the title said i need help with Autohydro...I have the manual but is very basic ( I have .gf model to practice) and i can`t find in the web anything more.

I would appreciate if anyone have some papers or a detailed procedure (.run) that can send me to lecon1313@hotmail.com.

Thanks.

[YoYoKamara]

what version of autohydro you use? try to use newer version to solve many problems.
manual is enough for it to learn

thanks
Trinh
Danang

[Leron]

I have v5.1.
Yes, maybe the manual could be enough...but a little more info will accelerate the learning.

thanks for the answer yoyokamara.

[ABoatGuy]

Check the GHSPORT.COM web site. Click "SUPPORT" in the upper left box on the home page and then "RUNFILES" on the next page. There are numerous examples of RUN files for all sorts of applications. This is GHS's website, but both programs have the same heritage and can read GF and Run files.

They tend to use macros a lot more than I've seen most users do, but you can easily see what is going on.

[Paul Kotzebue]

I've run into a couple of problems with AutoHydro vs. GHS. A few years ago I was getting some discrepancies using the AutoHydro floodable length command. To check it, I made up a flooded compartment with the watertight bulkheads spaced at the maximum floodable length for that location. Flooding the compartment and solving for that condition should bring the waterline right to the margin line. AutoHydro wasn't even close. GHS was spot on. However, the AutoHydro flooded condition matched the GHS flooded condition, so I concluded the problem was with the floodable length command.

More recently, I made a stability submittal to ABS with a MAXVCG curve generated by AutoHydro. I included my AutoHydro RUN file with the submittal. When ABS ran my RUN file using GHS, they got different results. I had to re-submit my calculations using GHS.

I haven't encountered any other problems with AutoHydro, but I'm still wary of using it. The Coast Guard and ABS use GHS to review submittals, so any calculations done with AutoHydro need to match GHS to be acceptable to them.

Naturally, bringing the aforementioned issues to the attention of the people at AutoHydro is futile.

[ABoatGuy]

Really interesting and a little troubling. Did ABS have your model?

Having a MAXVCG calc screwed up could get really expensive. Do you remember if it was high or low?

[Paul Kotzebue]

Yes, ABS had the same GF file I was using. The AutoHydro MAXVCG's were higher then the GHS MAXVCG's. We did not have as much stability as we were expecting. When I ran my RUN file in GHS, my results matched what ABS was getting.

AutoHydro has been consitent with GHS in producing righting arm curves and evaluating stability limits. After the ABS debacle I tried running righting arm curves with the VCG set at MAXVCG in both AutoHydro and GHS. GHS hit the stability criteria limits as expected, but AutoHydro did not. Because the AutoHydro righting arm curve matched the GHS righting arm curve, I suspect the problem is in the AutoHydro MAXVCG command.

[Leron]

thanks aboatguy i checked GHSPORT.COM web site and found interesting run files...