Jump to content
fishordie79

Center of Buoyancy. How to Find It?

Recommended Posts

Hey there TU community! 

 I made a glide bait body tonight that I am really happy about and I was thinking about the best way to weight it so that it sinks parallel and relatively slowly. I see a lot of people talking about "center of buoyancy" and I was wondering if you guys could give me some suggestions on some good methods of finding this. What I have done until this point is just kind of eye the bait, drill holes where I think they need to be, pour some lead and then do a swim test. Then I just add or reduce weight how I see fit until I achieve the sink rate/position I am looking for. This has worked fairly well thus far but there has to be a more scientific approach to this. What do you guys suggest?
 

Glider.jpeg

Link to comment
Share on other sites

You can move lead ballast around mounted externally outside the body of a prototype to get an idea how much weight you need and where to place it first for a particular design . Once you arrive at the weight required and drill into the lure body you will be losing a slight amount of buoyancy and slightly altering the center of gravity you had previously  established with the weight on the outside and may have to make slight adjustments . I have taken a drill and slowly removed lead from a weight I had glued in for ballast after testing to get the balance back after moving the ballast inside the body .

Not the scientific answer you were looking for but that's how I have done it …….

Edited by jigmeister
omission
  • Like 1
Link to comment
Share on other sites

When a lure is floating stationary, the CoB is ALWAYS directly above the CoG. This relationship determines whether the lure is nose up or down depending on where you fit your weights.

To find the CoB you can find the balance point of the plain, unweighted blank, over a knife edge or just your finger.

Dave

  • Like 1
Link to comment
Share on other sites

Before hardware is added (plain blank) it is the centre of buoyancy (CoB). After adding all the ballast and hardware it is the centre of gravity (CoG). If the two are the same distance from the nose then the lure will float level.

I use this information when designing a lure on CAD, arranging the ballast locations so that the lure is predicted to float in the attitude that I want.

Dave

  • Like 1
Link to comment
Share on other sites

On ‎11‎/‎10‎/‎2019 at 10:01 PM, Vodkaman said:

When a lure is floating stationary, the CoB is ALWAYS directly above the CoG. This relationship determines whether the lure is nose up or down depending on where you fit your weights.

To find the CoB you can find the balance point of the plain, unweighted blank, over a knife edge or just your finger.

Dave

well stated.

  • Thanks 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...


×
×
  • Create New...
Top