Predict flow lines along hull

Ok, interesting test, though a little "invasive" !

 

Dear Brother.... Can anyone help me to find the Load line for flat barge having the length of 19.90m, Braedth as 10.00m and depth as 2.00m

 

Best ask in another forum. This thread is about flow lines along a hull.

 

Smear

What kind of smear is the most suitable which is easy to remove after the experiment and do not discolor the hull?

js

 

I used artists' oil colour, e.g. Titanium white.
It can be thinned with turpentine oil.
After the test remove the paint with white spirit.
Uli

 

All in all I think that eyeballing, common sense and a little good luck is the preferred way to go whit my little ship. I was most interested if there where any rule of thumb when attaching bilge keels to a hull when taking flow lines in consideration. But when reading all posts I understand that the matter is to complex to solve in a simple way.
The most important thing that I'm trying to accomplish is roll dampening, if the flow along the keels creates more or less turbulense is of less importance. My mighty 24' ship is anyway only topping 6 knots at full speed so the turbulence created will not have much impact anyway.

 

You can draw a bilge diagonal in the body lines plan. That will allow you to get the points for which it will pass a flat bar, your bilge keel.

 

Does that apply to a fiberglass, "lapstrake", double-ended motorsailer without a parallel mid-body such as the Saga 24 which the original poster is interested in modifying?

 

Why not ?. Having said that turbulence does not care, could you tell us why not ?. Surely you have a compelling reason but I am not able to guess.

 

Of course I care about turbulence, but as the complexity to get the flow lines right is above my math skills I have to settel for something easier. Almost right is enough for me in this case and to mount them alog the hull following a slight curve will do the job just fine! It's at family boat after all, not a racer.
The case would be a lot easier if there was existing drawings available, but when I asked Saga boats, their answer was that they only have the mould left.

 

Janne Enlund, I understand you perfectly. You will not despise the turbulence but you don't want to take them into account given the complexity of determining water flow lines.
The method which I propose has been used by many large ships, before the tank test or software with 3D models allow determining those lines. But if you have no body lines plan, you can not use it. Maybe you could draw 4 or 5 cross sections and, with that, I could give you some guidelines to draw the line.

 

That would be much appreciated. I'll just have to wait until the snow has melted around the hull so I can make the measurements. Still winter in Finland...