# Seakeeper Question

Discussion in 'Software' started by squivo, Mar 29, 2006.

1. Joined: Mar 2006
Posts: 7
Likes: 0, Points: 0, Legacy Rep: 10
Location: Brazil

### squivoJunior Member

Hi everyone!

Is it possible do find out the hull natural frequency through the use of Maxsurf Seakeeper? If it is possible, how can I do that?

Thanks and Regards,

Luiz

2. Joined: Jul 2004
Posts: 4
Likes: 0, Points: 0, Legacy Rep: 10
Location: Australia

### GooeyNew Member

Seakeeper analysis produces roll, pitch and heave RAO graphs for different user specified seastates, speeds and headings. It also does Roll decay simulation. All output from Seakeeper is both in a graph and in tabular format as well as on screen animations (you can see the ship going through waves).

Seakeeper is used to calculate motion response spectra and from that do statistical analysis (eg slamming or green water probability). My seakeeping knowledge is a bit rusty, but I am sure that from all the output in Seakeeper you can get the natural frequency. Isn't the peak of the RAO graph the natural frequency? Also the roll decay animation: the ship will oscillate back to equilibrium at its natural frequency.

3. Joined: Mar 2006
Posts: 7
Likes: 0, Points: 0, Legacy Rep: 10
Location: Brazil

### squivoJunior Member

Thanks Gooey....I was wondering about it and I think you are right, in fact the unity in RAO represents that, because if the response goes more than an unity it means resonance ocurred...
By the way, I have a wave spectrum with wave probabilities in %, is there some way that I can insert this information on seakeeper?
Thanks

4. Joined: Apr 2006
Posts: 2
Likes: 0, Points: 0, Legacy Rep: 10
Location: iran

### moeedNew Member

seakeeper error!!

:!: hi dear,
i design a catamaran with L=18,B=6.5, at T=1, in auto cad, then translated in Rhino, and cover it with multisurface(loft, edge surf, rail surf,...) then save in iges format, and read in maxsurf pro.!!
i can calculated this model in hydromax, but when i try to evaluate the ROA in seakeeper, one message finished the calculation and error say to me " the hydrostatic calculation failed" !! :!:
thanks
best regard,
moeed.

5. Joined: Jul 2004
Posts: 4
Likes: 0, Points: 0, Legacy Rep: 10
Location: Australia

### GooeyNew Member

Hi Moeed,

I would recommend you contact Formation Design Systems technical support at support@formsys.com. They are known to provide excellent support within 24 hrs for users that pay their annual maintenance fees.

Cheers,

Gooey

Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.