Monitoring piles during installation

[Ray Shields]

Using an ROV to monitor progress of a pile as it is being hammered into the seabed, around what kind of dBs of soundwave pressure are the ROVs able to stand before starting to have to worry about blowing seals, cracking sonar ceramics etc.?

I’ve not done it before but given the force of the soundwaves produced I wouldn’t say its a healthy environment for an ROV to be hanging about unnecessarily!

[Anonymous]

blowing seals, cracking sonar ceramics…..very unlikely.

In the past we always lost the odd camera, but nothing to stop the job. The odd card moving in the older subs were the pods have seen better days. Things are so much more solid state, reliable and robust these days. Modern hydraulic hammers are very efficient at transferring their energy into the pile. With the ROV a few meters away, I doubt you’ll have too many issues.

[Ray Shields]

Cool, ta. Just thought I’d check 🙂 They are suggesting over 300dB @1m away which sounds a tad loud to me!

[Andy Shiers]

I agree with 225 , We used to have problems with the old steam driven Hammers but Not had any problems with the new Hydraulic ones.

[Savante]

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

[Robert Black]

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.

[DANFROV]

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

[Paul Robson]

We carried out some pile insatllation work in vietnam for DOF a few years back.
Didnt have any problems apart from how shallow the water was.

[Anonymous]

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.

[Deepanshu]

I agree with Kreuz as i was the one who packed a new sonar for that system and definately it got damaged by piling but it was not in 1-2 days,It took long time befoire it happened

[Anonymous]

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

[Ray Shields]

"Best endevours" are to be done for pile monitoring, and any damage will be paid for, just thought I would see how others have faired while pile monitoring 😀

[Mike McEwan]

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.

[andyrose]

Ray,

If you are having to monitor your piles during installation with an ROV – I would go see a doctor or perhaps try aqualube!!

[Ray Shields]

Ray,

If you are having to monitor your piles during installation with an ROV – I would go see a doctor or perhaps try aqualube!!

LoL, I’m out of Aqualube as all you can get is a cheaper Aquashield these days.

Luckily the Client also has 200kg of Vaseline to ease the pile insertion 😯

[Author]

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