Developing and Implementing Methods to determine the Hydrostatic properties of

Aeoliscus strigatus

Jeremy KeifenheimAdvisor: Dr. Thomas Consi

Figure 1: Side and front view of Aeoliscus strigatus, common name shrimpfish

Hydrostatic Properties and Methods

• Stability determined by the center of gravity and center of buoyancy.Center of Gravity (CG)• Utilized the plumb line method

• Finds 2D CG location• Fish was suspended from a pivot

point and allowed to rotate until equilibrium is achieved.

• Once at equilibrium, a plumb line is struck through the pivot point.

• Process repeated with new pivot point.

• The intersection of the plumb lines is the center of gravity on the corresponding two planes.

• Took images and superimposed to find intersection point.

Center of Buoyancy (CB)• Measured buoyant force of specific fish.

• Filled cylinder to known level.• Submerged fish in cylinder.• Removed water until at initial level.• Weighed removed water to find

buoyant force. • Hung fish from balance in rigid

orientation. • Raised a tank of water from below fish.

• Continued to raise tank until balance showed ½ buoyant force.

• Imaged fish.• Repeated with fish in different

orientation.• Superimposed images to find intersection

point.

Results and ConclusionsCenter of Gravity (CG)

Red horizontal line represents the level at which all three plumb lines intersect. The CG is shown to be located closely to the pectoral fin base.

Figure 2: Three superimposed plumb line images.

Center of Buoyancy (CB)• Due to the small stature of the fish,

precise measuring tools are needed and small forces can have a detrimental effect on the measurement results. For example, capillary action causes water to “climb” the fish as the tank is raised and small buoyant forces are offset by the additional weight of the water. Methods, such as chemical wetting agents, are currently being explored to counteract this effect.