Guide cables on roof air raising

[Marinel1]

See also thread1452-384612

As far I know there are at least two ways to assemble the guide ropes. The most comun is to pass the ropes throught the roof and use the pulleys bellow the roof shells in the periferic zone. Another way is to have the same pulleys on the top of the roof and use just one hole at the roof's center. What is the best solution?

 

[Syahar1975]

Dear Marine1,

There is another option i.e. the pulley above the roof plate near the shell plate. I did use this method.

But mostly the pulley under the roof.

Syah

 

[Marinel1]

Concerning roof air raising, i saw a Method Statment wher they talk about two types of pressure. The pressure that we need to mantain in equilibrium the roof, and a pressure to raise the roof. In that particular case they talk about 140 mmH2O for the fiorst one and 250 mmH2o for the second pressure. Why so different pressures? Is that pressure difference to take in consideration the seals from roof to concret wall?

Syahar, could you explain?