Freeship help

[ConcreteCanoe10]

Hi,
I am a third year civil engineer and co-caption of this years UMaine concrete canoe team. I am looking for some help with freeship. I have been using it for almost a year now and I have successfully drawn many canoes. However, I still do not understand a lot of the information FreeShip gives me about my boat, nor do I understand how to get the information I want.

I would really like to be able to put in a wall thickness and a density. I am also interested in drag, top speed, and anything else that might be useful.

Thanks!

[Guest625101138]

Thickness - enter the data in the "Layer" information window.

Drag - Freeship does not provide meaningful information on drag for a narrow craft like this. Better to use Michlet.

Top Speed - how many paddlers and what power can they produce? You can assume a paddling efficiency of 60% if average. Maybe 70% if they have good technique.

Rick W.

[ConcreteCanoe10]

thanks!

[verbertus]

Hi Rick,

Are you saying that the Kaper resistance calc ( John Winters), which is one of the drag calculations in Freeship+, is giving no meaningful information?

[Guest625101138]

Originally Posted by verbertus

Hi Rick,

Are you saying that the Kaper resistance calc ( John Winters), which is one of the drag calculations in Freeship+, is giving no meaningful information?

The version of Freeship that I have does not give any results for certain block coefficients that can be found with very efficient slender hulls. Where I have got results they do not compare well with Michlet and I have found Michlet gives very reliable results for efficient hulls.

I now have Delftship Pro and it has two empirical methods. They do work for high block coefficients. The results vary by 30% or more between the two methods in some situations. I am designing to within 3% using Michlet. The great benefit with Michlet is the in-built hull optimising routine Godzilla.

The wave drag in Michlet is determined using an analytical method whereas the others use empirical method.

Rick W.