Figure 136. Nonskid concrete ramp surface. 



pulled out just before the concrete has initially set. The sides of each stick should first be 

 planed to about a 0.062-inch taper before being nailed to the framing boards to facilitate 

 frame removal. A tap on the end of each stick before lifting will help to break any bond that 

 might form. 



Any part of the ramp that must be placed underwater should be precast in sections of a 

 size that can be conveniently shd or lowered into place onto a carefully prepared gravel bed 

 about 6 inches thick. One method that has been used successfully is to precast 6- by 12-inch 

 slabs that are a lane-width long, space them 3 inches apart perpendicular to the slope, and 

 fill the gaps with coarse gravel. Some submerged ramps have been tremie-poured, but often 

 with poor results and at a cost greater than that of a precast-slab ramp. Large concrete 

 bricks and building blocks have been used, but they tend to become dislodged easily if the 

 subgrade is soft. (See Portland Cement Association, 1965, for more detailed information on 

 ramp design.) 



A partial listing of manufacturers offering products related to small-craft harbors or 

 ancillary facilities is presented in Appendix E. All the manufacturers listed aided in the data 

 preparation by contributing solicited information about products, samples, or photos of 

 their proprietary items or systems. However, this is not intended to be a comprehensive list 

 of all marine product manufacturers, nor a special endorsement for those listed. 



194 



