COLLAPSE OF TEXAS TOWER NO. 4 173 



We were requested by Mr. Kelleher to further examine A cais^son to de- 

 termine whether or not any of the construction blocks and cable were pres- 

 ent. This request was carried out, and we found two double sheave blocks 

 on A caisson in the same position as had been previously found on B caisson. 

 These were cleaned, rigged, removed, and salvaged. These four blocks that 

 had been salvaged were thoroughly cleaned and used as an example of the 

 cathodic protection substantiating the previous opinion that the protection was 

 very effective. 



Re item III : The third item in the contract stated that we were obligated 

 to assist in the locating of an oil leak in A caisson. We made several exploratory 

 dives from zero to minus 165 feet and did not locate a leak. During these 

 periods, a fluorescent dye was mixed into the oil in A caisson. The quantity 

 of oil in A caisson was increased to insure a greater depth of oil and to in- 

 crease the head pressure. After such time as the dye had thoroughly mixed 

 in the oil, we made further exploratory dives. 



The leak was indicated by the brillant oil slick at the surface of the water. 

 We found the oil leak at the minus-63-foot level of A caisson. The hole 

 was approximately 7 inches above the top of the collar and 8 to 9 inches to 

 the left of the top Dardelet bolt hole on the outside of A caisson. It had the 

 appearance of being a burned hole larger on the outside than it was on the 

 inside, approximately one-half inch in diameter and in the area of the in- 

 ternal concrete plug. We drilled, reamed, and tapped to insert a i/2-ineh 

 pipe plug. After this operation was completed, the oil slick at the surface 

 stopped and we saw no evidence of any other leak. 



However, on gaging the oil ullages, we found a 4-inch loss of liquid in 24 

 liours. This developed that there had to be another leak. At this time there was 

 no apparent oil slick. We further increased the volume of oil in A caisson and 

 there developed another oil slick. 



This slick covered a greater area than the previous slick. We investigated, 

 and found the leak to be within the bounds of a 2-foot-square area in the upper 

 section of A caisson collar between the collar holding bolts and the upper 

 Dardelet bolts. 



A portion of the oil was leaking out of the top left-hand Dardelet hole; the 

 remainder upward between the collar and the caisson. We drove a wooden plug 

 into the upper left Dardelet hole endeavoring to further determine whether the 

 leak could possibly be in the area directly behind the Dardelet holes or leaking 

 to the left of the Dardelet holes with such force so as to tunnel a path in the 

 marine growth between the collar and the caisson at the upper left Dardelet 

 hole. Upon the insertion of the plug, we appreciated a slight leak in the upper 

 center and the right Dardelet hole. However, the upward volume was greater 

 increased. Weather conditions permitted no further investigation at this time. 



The weather conditions did not give sufficient light for photographic defini- 

 tion ; that is, of the 70 exposures developed, we did not have distinction or light 

 sufficient to use the photographs to substantiate the survey. 



We examined C caisson in its entirety and found all solid connections to be 

 intact and in excellent condition. We examined the horizontal bracing at the 

 minus-77-foot level and also at the minus-135-foot level and found all to be in 

 ■excellent condition. 



Respectfully submitted. 



A. D. Crockett. 



Note. — For the record, we installed a rubber expanding pipe plug in the out- 

 let of the air operated valve at the minus-140-foot level on A caisson. This plug 

 was installed to insure no water loss in A caisson while we were endeavoring 

 to determine the whereabouts of the oil leak. 



Marine Contractors Co., Inc., 

 East Boston, Mass., June 26, 1959. 

 Resident Officer in Charge of Construction, 



Texas Towers, First Naval District PuUic Public Works Department, Boston, 

 Mass. 

 Dear Sir : As instructed in our present inspection contract N.B.Y. 27190, we 

 are pleased to submit the following summarization. 



