What is the quietest DPV?

[Wookie]

Hey, now. I work with the SF dive school in Key West. They use the Sea Doos in the pool. But actually, a lot of the SF divers come here to test Diver Delivery Vehicles of all sorts. Seems a big RFP just hit the street for new DDVs. We provide them boats unless they are diving at the school or in the inner mole.

 

[Bryan@Vintage Double Hose]

Voit Porta Sub.....Mike Nelson approved.

 

[Bryan@Vintage Double Hose]

Everybody and their mother claims that the military uses their stuff, with varying degrees of accuracy to the statement. If some former SF dude buys one for his kids to use in the pool, or the some supply sergeant buys a couple for the rec shack, some companies will claim that there products are in use with "special forces divers." Other will say that if some organization buys a couple for testing, say the NEDU buying a couple for comparison. Some won't even claim that even if they've got a legit contract.

Saying that the military uses it is about as accurate as saying "aircraft grade aluminum."

99% of the people that contact you asking for X for evaluation by X military unit are full of S**T and will fail miserably once put to the litmus test. Most are wannabees, might have beens, and out and out posers. Once you cut though all that the 1% have a real interest and defined reasons they want to evaluate a piece of equipment. It will be a long, drawn out, painful and frustrating process if and when it gets approved.

 

[JohnnyC]

99% of the people that contact you asking for X for evaluation by X military unit are full of S**T and will fail miserably once put to the litmus test. Most are wannabees, might have beens, and out and out posers. Once you cut though all that the 1% have a real interest and defined reasons they want to evaluate a piece of equipment. It will be a long, drawn out, painful and frustrating process if and when it gets approved.

You forgot, "and you'll get paid sometime next fiscal year. Maybe."

 

[Jon Nellis]

Hi Pete,

Get together with Peter and he'll show you how quiet a Genesis is, at least at normal speed. The motor switching noise gets louder at high power levels, but so does the water flow past your ears at that speed, which also creates noise. What you will likely find more important than noise, is how easy or difficult it is to control the speed of each DPV while diving. That's where the Genesis shines.

As for the technical answer to the questions, there are a few of things that we do to reduce motor noise, which mainly has to do with winding configuration. Most of the noise comes from the motor controller switching with a trapezoidal control, which is a bit noisier, but more efficient than sinusoidal control. High frequency switching is also a bit quieter, but also less efficient, so there has to be a balance point that each design tries to achieve. Since range, size and weight are generally more important to people than noise, we opted for a trapezoidal control for increased efficiency. Very little noise comes from the propeller on most DPVs, unless it is hitting the shroud or it is a small diameter propeller, spun extremely fast.

At normal cruising speeds, the Genesis is very quiet. At high power, you will hear the motor controller switching. When you hear noise on the numerous online videos of different DPVs it usually depends on whether the camera is on the diver or hard mounted to the DPV with any sounds vibrations conducting directly to the camera housing. Video editing software also can reduce or amplify the sound, so videos of a DPV are not a good gauge of noise.

Cheers,
Jon

 

[DA Aquamaster]

Pete, if you are looking for quiet, it's hard to beat an Oceanic motor and prop based scooter using a slower wound motor with a lot of prop pitch.

The motors in these scooters (Mako, Gavin, etc) are direct drive and fixed speed based on the motor winding, but vary from as low as 650-700 rpm (in some of the Makos) to 900-1000 rpm in scooters with aftermarket hotter wound motors. They are in general about as quiet as a scooter gets in the water.

There's also a difference between the sound you hear in a video when the camera is mounted on the DPV and what you actually hear in the water. Motor noise conducted directly to the camera via the scooter it is attached to is always louder than what you hear through the water.

 

[tbone1004]

Pete, if you are looking for quiet, it's hard to beat an Oceanic motor and prop based scooter using a slower wound motor with a lot of prop pitch.

The motors in these scooters (Mako, Gavin, etc) are direct drive and fixed speed based on the motor winding, but vary from as low as 650-700 rpm (in some of the Makos) to 900-1000 rpm in scooters with aftermarket hotter wound motors. They are in general about as quiet as a scooter gets in the water.

There's also a difference between the sound you hear in a video when the camera is mounted on the DPV and what you actually hear in the water. Motor noise conducted directly to the camera via the scooter it is attached to is always louder than what you hear through the water.

the SS UV/Viper with the speed controller are relatively quiet on speeds 1/2 as well

 

[Superlyte27]

Let's go diving. You use the UV, I'll use the Genesis. Then we'll switch and see what one you like the best.

 

[tbone1004]

Let's go diving. You use the UV, I'll use the Genesis. Then we'll switch and see what one you like the best.

at $1200 and my preference to go 100-150fpm, I'll suck up the extra 50lbs and save $5500. I'll still take you up on it though as it's the one scooter I don't have any direct experience with and really want to

 

[The Chairman]

Let's go diving.

I'm not going to say "no". When/where do you want to hit it?