The document presents a proposal for replacing the dock and installing a wave attenuator at Pier 4 Condominiums. It discusses factors that influence wind and boat wake waves at the site and how to determine the appropriate size and design of an attenuator. Calculations show that a 17-foot wide attenuator would be effective given the site conditions. Tank testing data was analyzed to develop attenuation calculations used in wave attenuator designs.

1. PIER 4 CONDOMINUMS Dock and Wave Attenuator replacement proposal Presented by Bellingham Marine June 29 th . 2005

2. Existing Conditions at Pier 4 Condominiums:

3. What’s the COST of a Wave Attenuator? Wave Attenuators are the most site specific designed structures in a marina. Can’t you give me a SQUARE FOOT NUMBER?

4. Different shapes and mass;

5. Different Drafts

6. Different Widths.

8. How does God make waves? WIND!

9. Wind blows, creating friction on the surface of a body of water.

10. What Factors Create and Effect Wind Generated Waves ? Wind Duration Wind Speed Fetch Water Depth

11. Fetch Fetch (n) : a) The distance over which a wind blows. b) The distance traveled by waves with no obstructions

12. Wind Speed – The average wind velocity over a 3 second gust. Wind Duration – The length of time the wind blows in minutes or hours. Water Depth – The depth of the water during the wind event.

13. How does Man make waves? BOAT WAKES!

14. Boat Wakes: Under certain conditions the prevailing cause of waves incident to a facility could be boat wakes. They are more frequent than extreme wave events and will lead to structural deterioration by cyclic fatigue.

17.      The right size and configuration of a attenuator will create a calm basin for this specific site.

21.      

22.     = =

23.             √  ≈    

24.  .    

26.  ”   “”  WAVE TRANSMISSION TABLE GIVEN WAVE PERIOD AND ATTENUATOR WIDTHS PERIOD LENGTH WIDTH 8 9 10 11 12 3.5 63 0.13 0.14 0.16 0.18 0.19 3.25 54 0.15 0.17 0.18 0.20 0.22 3 46 0.17 0.20 0.22 0.24 0.26 2.75 39 0.21 0.23 0.26 0.28 0.31 2.5 32 0.25 0.28 0.31 0.34 0.38 So for Hs = 3.0 a s shown in the Wave Tank example; KT will as shown below PERIOD LENGTH WIDTH 8 9 10 11 12 3.5 63 0.55 0.45 0.42 0.40 0.38 3.25 54 0.50 0.41 0.40 0.38 0.34 3 46 0.41 0.38 0.34 0.31 0.30 2.75 39 0.36 0.32 0.30 0.29 0.28 2.5 32 0.31 0.29 0.28 0.27 0.28 So for Hs = 3.0 as shown in Wave Tank example; Hs = 3.0 HT will as shown below PERIOD LENGTH WIDTH 8 9 10 11 12 3.5 63 1.65 1.35 1.26 1.20 1.14 3.25 54 1.50 1.23 1.20 1.14 1.02 3 46 1.23 1.14 1.02 0.93 0.90 2.75 39 1.08 0.96 0.90 0.87 0.84