Monitoring piles during installation

Did a few days of hydrohammering with Fugro two years ago Ray. Monitoring penetration depth using a tiger; nothing untowards to report !

I spent years monitoring Pile driving on the Hermod and the Odin, using an RCV 225. No real big issues.

We had no sonar at that time, only external tool was a divers compass so we knew roughly where we were going.

DanFrov

300db at 1m sounds high….

310dB Krakatau volcanic eruption 1883. Cracked one foot thick concrete at 300 miles, created a 3000 foot tidal wave, and heard 3100 miles away, sound pressure caused barometers to fluctuate wildly at 100 miles indicating levels of 190db at that distance from blast site. Rocks thrown to a height of 34 miles.

I’ve just had a four grand repair bill for a Seaking Sonar after five minutes of pile monitoring. Unless the viz is good allowing for good seperation; don’t agree to it.

Never heard of a sonar failure as a direct consequence of hammer piling observation. Rubbish returns yes, damage no. However, I’m guessing you spend alot more on manip spares over the year, but them big crane hooks aren’t going to unhook themselves.

Observing hammer pilling or doing heavy construction. I know which is the riskier task. As for not agreeing to it….. Next company please step forward

Hi,
We spent years monitoring piling on the Hermod and Thialf with no ill affects. We had 1 work class monitoring the hammer and another at the pile sleeve. We just used to turn the sonars off.
Strangely a couple of years ago we did a windmill job where we were told we couldn’t be in the water during hammering. The difference being that the windmill client refused to accept all the risks.