EXHIBIT "A" 

Case 2:03-cv-04822-RBS Document 70-4 Filed 08/27/2009 Page 1 of 12
DAVID P. POPE, PH.D.

624 ST. ANDREW ROAD

PHILADELPHIA. PA 19118

PHoNE: 215-247-7234

FAX: 215-247-7554

11/26/06

John T. Donovan

Rawle & Henderson

The Widener Building

One South Penn Square

Plnladelphia, PA19107

RE: Revak v. Locatum,.et al

Dear Mr. Donovan,

I am writing to repOli to you the results of my investigation into the cause(s) oftlie sling'

failure in the subject accident.

In the course of my investigation I examined or reviewed the following items:

1. The subject slig. I also photographed it, and a CD contaii1Ig these photographs

is attached to tbis report

2:. TIie second amended complaint.

3. Copies of color photographs that you supplied to me.

4. A ëD of photographs from the offces ofE. Powers.

5. The depositions of: Revak, Bijerk, Lukassen, Strjland, Kuursta, Häggkvist,

Eriksson, Mattson, Johansson and Ogren.

6. The:"!:ep'o~i.ofRobeii A. Erb, Ph.D.

Mr. Revak was injured by a bundle oflumber that fell on 1i when an endless polyester

liftng sling failed. You' asked me to determine, if possible, why the sling failed.

Accordiiig to the deposition testimony, the. draft oflumber that fell on Mr. Revak

consisted of 4 or 5 individual bundles, weighing approxiinately 1100 pounds each, for a

total weight of 5500 pounds, assumiiig five bundles in the draft. Two endless. 

lifting

slings, each of which had a working load limit of 2000 kilogranis (4400 pOllids)

sUPPOlied tins weight. (Clnef Officer Lukassen said in 

Ins deposition that the slings have

a safe working load of 3500 kilograms or 7700 pounds. I believe he was mistaken

because the green color ofthe Sliiig indicates it to have a 2000-kilogram working load

limit. The label is missiiig fì:om the sling, so the working load limit must be inferred from

the color.) The two slings combined had a total capacity of 8800 pounds in a straight pull,

compared .to an actual weight in the draft of 5500 pounds, but the pull was not straight, so

the working load limit must be commensurately reduced. Given the dimensions of the

bundles and the length of the straps, the effect of tins angle is to reduce the working load

limit by only about 15%. Thus llider these conditions, the safe working load of 

the two

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Case 2:03-cv-04822-RBS Document 70-4 Filed 08/27/2009 Page 2 of 12
slings combined was 7480 pounds, compared to the actual weight in the draft of 5500

pounds (with five bundles oflumber). This calculation shows that the sling was not

overloaded at the time of the accident.

When a damage-free sling is loaded to its working load liniit it will definitely NOT fail,

since the working load limit is much smaller than the breaking load of the sling. In fact,

tiie working load limit is required by European Standard EN 1492-1 to be no more than

one seventh of the breaking strength oftlie sling. Therefore the subject sling would be

expected to break at a load of7 times 7480 pounds, or 52,360 pounds. The fact that this

breaking load is almost ten times larger than the load placed on it at the time of the

accident indicates that the SlUig had been severely damaged prior to the accident. In the

following I consider possible sources of that damage.

Except for the fracture in the subject sling and a deliberate cut made after the accident,

the sling shows little damage. The surface of the sling is abraded in some areas, but only

a very small fì:action of the fibers is significantly damaged. Also, some fibers are cut ili

some localized areas, but, again, the number of cut fibers is a very small fraction ofthe

total. Since the strength of the sling is detemiilied by the fraction of un dar aged fibers,

the damage to the fibers outside the failure zone reduced tiie breaking stI-ength of 

the

sling by only a few percent. Samples oftbis damage are shown in Photographs #1 and 2.

I now consider the specific aTea of the fracture, as shown in Photograph 3. This

photograph shows the two sides of the fractme placed end to end in their COlTect relative

orientations. Most of the fractue surfaces consist of a relatively straight portion that is

perpendicular to the axs of the sling. The length oftbis section is about 50 in of tiie 60

n1l width of tiie strap, indicated by 'pinched/cut' on tiie photograph. The second portion

of tiie fì:actue surface consists of a 10 min wide 'tai' attached to the right side with a

matching area on the left side. In addition, the 50 nun long section all the left side

undeiwent considerable lateral contraction, as shown in the photograph, while the right

side underwent little or no contraction. The absence oflatera1 contraction on the right

hand side indicates that tIs side was subj ected to much smaller loads at failure than the

left hand side. Fuiihennore, the left side of the fracture is abraded in the direction shown,

and this abrasion teiminates on a 'nub' of polypropylene fibers on the right side of the

fracture. All these features poilit to tiie fact that the 50 11m long pOliioii of the fì:acture

resulted from the sling having been pinched between a fixed object and the load during

lifting. Under such a condition, the left.sideof the fracture was placed under vei)' hi.gh-... .. '" .... .. .. ., .. ... ..., .

stress while the iight side bore a much smaller load, resulting in both the pinching/cütting

of the sling along the SO nUll length of the fracture and the lateral contraction on the left

hand side. After the sling was cut, no more than a 10mm wide section of the sling was

canyiiig the load, see' 10 lllTI wide remaining ligament' on the photograph.

Based on the above observations of the fi:acture surface and the surrounding area, I

conclude that the damage reduced the strength of tiie sling by at least 80%.

The two sides of the :f:acture ill Photograph #3 show. no otIier differences, for example,

no differences in soiling, indicating that the damage to the sling OCCUlTed relatively

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Case 2:03-cv-04822-RBS Document 70-4 Filed 08/27/2009 Page 3 of 12
recently relative to the time of tiie accident. Damage of the type described here is not

uiicommoii, for example, see pages 53 and 54 ofMr. Eriksson's deposition.

Given that the sling was so severely damaged prior to tiie accident, and that it failed

while the load was just being slightly repositioned, it is highly unlikely that it could have

withstood the forces required to lift the draf out ofthe ship. Therefore the damage

occurred during the lift itself, i.e., the draf pinched the sling against a portion of 

the ship

while it was being lifted from the slnp in Philadelphia.

In summary, I conclude the following to a reasonable degree of engineering ceiiainty:

The subject sling was damaged and its load beaiing capacily was reduced by at least 80%

wlnle the draft was being lifted from the ship in Philadelplna. The remaining seg11entof

the damaged sling could just cai1Y the dead load ofthe draft, but a small increase in the

load, as caused by moving the load as it was being positioned above the dock,was

sufficient to break that remaining small segment. There is no evidence that tiie sling was

dainaged to tiie point of being unsafe prior to the final lift in Philadelphia, rather, tiie

damage leading to the failure was introduced durig tIns final lift. It is also likely that the

label was tom fi'om the sling by tI1Is same event.

Sincerely, Ð~P~

David P. Pope, Ph.D.

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Case 2:03-cv-04822-RBS Document 70-4 Filed 08/27/2009 Page 4 of 12
. Photograph # 1. An area of abrasive wear on tiie sling. Note the absence of cut fibers.

Photograph #2. An area of abrasive wear with some cut fibers, see arrow.

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Case 2:03-cv-04822-RBS Document 70-4 Filed 08/27/2009 Page 5 of 12
remaining

ligament

Photograph #3. The fractue site on the sling. Piior to the accident 50mm of 

the 60 lTI

CTOSS section was cut, leavig only a 10 lIDTI remaining ligament to ca. the load.

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