Since I have a mild amount of high frequency hearing loss, I thought I would measure the sound levels on our 2014 R31 while underway at 13 knots. Displacement speed (7.5 kts for the R31) would have lower decibel levels.
I used a Fluke 945 sound meter for testing. For all the measurements, I held the meter in front of me at ear level. The Fluke meter was set for slow, which averages the sound levels every 1 second. The meter was set for A weighting (general sound levels). I didn't see any significant difference between A and C weighting. The C weighting emphasizes lower frequency sounds.
All of the windows were closed during the testing. Opening the stern or helm doors did increase sound levels as noted below. The boat was running on auto pilot at 13 kts on a calm day. Throttle positions were not changed. My wife was at the helm when I did measurements at locations other than at the helm!
Location Sound level in db
Helm (doors closed) 67
Helm, helm door open 70
Standing inside at stern door 74
Standing inside at stern door with engine hatch open 77
Standing in cockpit over engine hatch (closed) 83
Standing in cockpit with engine hatch open 103
The decibel system of measuring is logarithmic. We perceive an increase of 10 decibels as being twice as loud but the actual sound intensity is 10 times more intense! Hearing loss is directly correlated with sound intensity rather than our perception of the sound level.
The CDC studies show that sound levels under 70 decibels on a sustained basis are not known to cause permanent hearing loss. At a decibel level of 100 db permanent hearing loss occurs after 15 minutes. This damage is cumulative over our lifetime. At a decibel level of 105 db, permanent hearing loss occurs in 5 minutes. There is a good discussion of hearing loss on the CDC's website here https://www.cdc.gov/nceh/hearing_loss/what_noises_cause_hearing_loss.html.
Ranger Tugs has done a good job of decreasing engine sounds in the cabin while underway. Since we may be at the helm for hours at a time I was curious to see what the sound exposure is and whether it would cause hearing loss. At a measurement of 67 db with all doors closed, and at 70 with the helm door open these should be safe levels based on CDC data. I was impressed at how much difference there was between the cockpit area (which has a full enclosure on our boat) and the cabin area. I was also impressed with the reduction of sound by the engine hatch. This hatch has sound reduction material attached to it. There was a 20 db difference with the hatch shut and open, or 100 times more sound intensity!
At the levels I noted, permanent hearing loss would happen with only 5-15 minutes of exposure with the engine hatch open. If I go check the engine compartment underway, I wear hearing protection and you may want to as well!
I used a Fluke 945 sound meter for testing. For all the measurements, I held the meter in front of me at ear level. The Fluke meter was set for slow, which averages the sound levels every 1 second. The meter was set for A weighting (general sound levels). I didn't see any significant difference between A and C weighting. The C weighting emphasizes lower frequency sounds.
All of the windows were closed during the testing. Opening the stern or helm doors did increase sound levels as noted below. The boat was running on auto pilot at 13 kts on a calm day. Throttle positions were not changed. My wife was at the helm when I did measurements at locations other than at the helm!
Location Sound level in db
Helm (doors closed) 67
Helm, helm door open 70
Standing inside at stern door 74
Standing inside at stern door with engine hatch open 77
Standing in cockpit over engine hatch (closed) 83
Standing in cockpit with engine hatch open 103
The decibel system of measuring is logarithmic. We perceive an increase of 10 decibels as being twice as loud but the actual sound intensity is 10 times more intense! Hearing loss is directly correlated with sound intensity rather than our perception of the sound level.
The CDC studies show that sound levels under 70 decibels on a sustained basis are not known to cause permanent hearing loss. At a decibel level of 100 db permanent hearing loss occurs after 15 minutes. This damage is cumulative over our lifetime. At a decibel level of 105 db, permanent hearing loss occurs in 5 minutes. There is a good discussion of hearing loss on the CDC's website here https://www.cdc.gov/nceh/hearing_loss/what_noises_cause_hearing_loss.html.
Ranger Tugs has done a good job of decreasing engine sounds in the cabin while underway. Since we may be at the helm for hours at a time I was curious to see what the sound exposure is and whether it would cause hearing loss. At a measurement of 67 db with all doors closed, and at 70 with the helm door open these should be safe levels based on CDC data. I was impressed at how much difference there was between the cockpit area (which has a full enclosure on our boat) and the cabin area. I was also impressed with the reduction of sound by the engine hatch. This hatch has sound reduction material attached to it. There was a 20 db difference with the hatch shut and open, or 100 times more sound intensity!
At the levels I noted, permanent hearing loss would happen with only 5-15 minutes of exposure with the engine hatch open. If I go check the engine compartment underway, I wear hearing protection and you may want to as well!
