J-tube cable pull-in load calculator


All products are in English, except as indicated on specific product pages. Annual subscription includes all future product updates as long as subscription is paid. Perpetual licenses as forever, however, major future product updates will require an upgrade purchase. Apps that are excel-based work on Windows PC, with Windows parallels needed to run on Macs. File Download links are shown immediately after purchase, and also sent by email. The product needs to be activated upon purchase. The activation key is sent by email after the purchase and has the format "email address-order number". For example, if the email address used for the purchase is [email protected], and the order number is 9999, the product key is [email protected] For any issues post purchase, write to [email protected]
Report Abuse


What does this App do?

Offshore cables and pipelines are usually pulled in through J tube to a turbine tower or substation. A pull-in winch is installed to pull in the flexible. While the cable tension outside J tube is governed by the catenary properties controlled by vessel positions and tensioner control, the J tube adds additional tension due to gravity,friction and bends. This sheet is used to estimate the tension at the top of J tube by considering the gravity, friction and bend angles. At the bends, the sheet uses Capstan equation[Eytelwein’s formula] to evaluate the loads at the end of the section, at the end of the sheet, the final load on the pull-in winch is evaluated.

How to use this app?

User can add straight sections or bends with their properties
Upto 20 sections can be added
The properties of each section or bend are evaluated, and the cumulative property is also calculated
The input cells are all in blue. All parameters are in SI units

“- J tube is modelled from BOTTOM to TOP. Bottom end ( bellmouth end) is located at X=0 and Z=+ve from seabed.
– The friction coefficient application is automatic and refers to starting of the Z value of the section. if the Z is below water line, water based friction coefficient is used. When the J tube passes through water line, the section maybe split at the water line, to split the friction coefficient application. ” 

The app is based on the Eytelwein’s formula (or Capstan equation) 

Tload is the applied tension on the line
Thold is the resulting force exerted at the other side of the capstan
μ is the coefficient of friction between the rope and capstan materials
ϕ is the total angle swept by all turns of the rope, measured in radians

“Several assumptions must be true for the formula to be valid:

1. The rope is on the verge of full sliding, i.e. Tload is the maximum load that one can hold. Smaller loads can be held as well, resulting in a smaller effective contact angle ϕ .

2. It is important that the line is not rigid, in which case significant force would be lost in the bending of the line tightly around the cylinder. (The equation must be modified for this case.) For instance a Bowden cable is to some extent rigid and doesn’t obey the principles of the Capstan equation.

3. The line is non-elastic.”

Revision History
20-Nov First Issue



There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.

Questions and Answers

You are not logged in