There are different types of cribs (look different). Dock cribs look like the one RobA posted (good link RobA). There are also fish cribs (I will find some pics). Both dock and fish cribs are great structure.
Here is a link. Crib is another name for fish structure and has many forms. Here are some. Most use logs or pallets. Some have rocks some brush some are open.
http://www.chetek.com/clpa/cribs.htmHabitat Manual for Use of Artificial
Structures in Lakes and Reservoirs
Compiled by the Southern Division AFS Reservoir Committee
Log Cribs
Log cribs consist of square log structures and may contain several layers of brush (e.g., Wisconsin log crib).
Click here for map of states that used this method.
Main reasons used:
- availability of materials
- low cost
- preference for natural materials
- longevity
- ease of construction and installation
- interest of anglers
Reported advantages:
none reported
Reported disadvantages:
none reported
Recommendations:
none reported
Mean reported time to create/place one structure/unit: 17 hrs (range 0.25 - 60, n=4)
Mean reported life of structure/unit: 25 yrs (range 15 - 50, n=4)
Degrees of Satisfaction:
**average ratings on a scale of 1 - 5 with 1 being very satisfied and 5 being very dissatisfied.
- fish attractor to increase angler catch and harvest 1.0 (n=2)
- recruitment 1.0 (n=2)
- adult habitat/sanctuary 1.5 (n=2)