How Loud Is a Hydrofoil?

[Mister Muso]

I'm going on holiday next month and one of the trips we're looking at booking is a trip on a hydrofoil to a nearby island (Sorrento to Capri in Italy).

How loud are these exactly? Is it as bad as a speedboat? I wouldn't think so as it's designed more to glide along the surface of the water, so there should be less resistance. If I double-protect with foam earplugs and earmuffs, should I be OK for up to half an hour say?

I'm three months into my first serious tinnitus spike, still got some hyperacusis and needing to avoid lawn mowers etc, so I'm thinking of breaking it to my family that I may not be able to do this. That's all assuming I survive the flight out there of course.

 

[Earing]

Aboard a boat you are subjected to both high frequency and low frequency waves from the engine and the forces of the boat meeting resistance while in motion. You feel the low frequency waves as vibration — which over time can cause physical fatigue.

 

[Earing]

https://www.boatingmag.com/how-noise-levels-affect-boaters/

Typically, our idle speed test numbers fall in the 60s, the same level as a casual conversation. As the boat climbs on plane, the engine noise revs up into the 70s. Then it climbs into the 80s at cruising speeds and into the 90s as it nears wide-open throttle; some noisy boats hit the 100s.

Here's the builder's issue: Its engineers recorded sound levels using a slow-weighted dbA scale, but with a special filter that reduced wind noise. We don't use those. Wind noise is a real-world factor on boats.

On long runs, think of those OSHA workplace standards. And remember this: The Coast Guard limits watches to four-hour shifts to prevent fatigue. Try to limit your helm time to two or three hours. Take a break, catch your breath, and clear your head. You'll be a safer, and more relaxed, boater for it.


Where the Sound Comes From
1. Engine Noise: Even today's quieter engines still produce sound that affects you.
2. Wind Noise: On open helms, wind noise becomes a significant factor.
3. Water Hitting Hull: Resistance creates vibration.

 

[Mister Muso]

Typically, our idle speed test numbers fall in the 60s, the same level as a casual conversation. As the boat climbs on plane, the engine noise revs up into the 70s. Then it climbs into the 80s at cruising speeds and into the 90s as it nears wide-open throttle; some noisy boats hit the 100s.

Oh dear, that doesn't sound too good!

I'm not going to be piloting one, just a passenger. So if there is a "downstairs" section, I guess I would be more protected from the noise going down there, if I have that option, rather than up on the open deck?

As it's a short trip (a ferry takes half an hour, so for a faster boat like a hydrofoil I'm guessing 10 minutes) then it may not hit top speed for long. Alternatively I may try and book us onto a slower boat instead.

 

[Earing]

Oh dear, that doesn't sound too good!

I'm not going to be piloting one, just a passenger. So if there is a "downstairs" section, I guess I would be more protected from the noise going down there, if I have that option, rather than up on the open deck?

As it's a short trip (a ferry takes half an hour, so for a faster boat like a hydrofoil I'm guessing 10 minutes) then it may not hit top speed for long. Alternatively I may try and book us onto a slower boat instead.

I only Googled "hydrofoil dB levels" and the info I posted came up. Hopefully you can find a workaround so you can enjoy your holiday. It would be best to get the make and model of the boat. Hydrofoil seems to be a generic term for a type of fin, not a boat style.