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This Searover compass maybe the compass to use with the Genesis DPVs. I use a Suunto SK8 compass in a wrist mount, which is much smaller. Perhaps the smaller size makes the SK8 more susceptible to the EMF interference. I've posisitioned it everywhere along the length of the body with the same results. I have a dive buddy that just uses his wrist compass as well and he doesn't have any issues navigating. It will be a small learning curve for me. Don't laugh but I use to have one of these compasses made for kayaks. Worked extremely well on my SS Viper, but I just did not like... the look of the DPV with big wart on the hull (I deserve a flogging for this)... Likewise, the digital compass of my Perdix did not fare well with the EMF and had similar deviation.

My G2.1 is seutp for salt water. I will spend a dive to figure out how much weight I need for trim but I may leave the DPV slightly positive. I wonder if the DPV had a longer body, if it would make trimming it any easier? Mind you, I have an accounting degree so don't place much faith in my ideas regarding engineering... This is how I've set up my G2.1 I slip the key through the bolt snap of my front leash. I've added a very thin strip of electrical tape to the key's rubber band. It makes it easier to remove. I've replaced the original front strap that was very thin with 2 inch webbing. The one that I use is fairly soft but I will replace with a stiffer webbing.

View attachment 595591 View attachment 595592
The suunto has a very small needle so yes its much easier to mess it up with anything magnetic including electrical current.

The searover has a fat chunk of iron in it. Takes far more of a magnetic field to move it.
 
The searover has a fat chunk of iron in it. Takes far more of a magnetic field to move it.[/QUOTE]

My Sea Rover compass cannot ride flat on the DPV. Too much deflection. I'm working on finding how far above the magnet field to give true reading. What are you doing to get a true reading?
 
My searover is probably 6 or 7 years old and its mounted about 3/4 of the way forward on the tube. It matches other compasses and doesnt deflect when the scooter is on vs off. I have an older model Genesis 1200 tube with a warpcore retrofit inside. You tube is quite a bit shorter than mine
 
gbeasley:

Thanks for reviving this thread. Your posts made me rethink the compass on my G2.1. The deflection of my SK8 compass on the body of the G2.1 is not that bad at all, depending on its actual position on the hull of the DPV. Definitely do no put the compass directly below the handle on the propeller shroud. The compass went crazy there. Along the entire hull my SK8 varied by 40 to 80 degrees, apart from one spot where it only moved but 10 degrees. In all honestly, we cannot navigate precisely enough underwater where 10 degrees creates a meaningful trajectory variance.

Position the rear rubber band that covers the monofilament hull retainer so that it just covers the gap between the hull and motor. Place the compass forward by another full width of the rubber band. At this position, the compass only moved by 10 degrees on full load. I had previously used an SK7-8 with a sizeable air bubble within the capsule (threw it away). Perhaps this adversely affected the rotation of the card. A 10 degree variation will not impair underwater navigation to any meaningful degree. At the nose, where I would have prefered to position the compass, the card deviated by about 60-80 degrees, which would really get me into trouble.

20200705_095908.jpg

Going to bungee the wrist mounted compass that I just ordered from DGX and slide it over the full. I have plenty of 2 inch webbing and spare anti slip pads, commonly used on the cam bands of BCDs, which I can place under the mount to prevent slipping.
 
My Sea Rover compass cannot ride flat on the DPV. Too much deflection. I'm working on finding how far above the magnet field to give true reading. What are you doing to get a true reading?[/QUOTE]

I made my float that offsets bottom weight (9 oz) as part of the stand to get my Sea Rover out of the DPV magnetic field. It can probably be 3/4" lower with an 8 oz weight, but I'm happy with it. It will float in fresh water in perfect alignment with only the bolt snap touching the ground. So I can unsnap it and leave it floating 18" above the sand if I want do something without it. If I don't need the compass I can lay it down. The compass has zero deflection at full power underwater.
DPV2 compass.jpg DPV compass.jpg
 
Gbeasley:

Are you sure about the compass mount? Seven of my fellow dive club members have Genesis 1200 DPVS with your compass. The compass sits on the hull just fine. I mounted the wrist compass that I purchased from DGX onto the hull of my G2.1. This location, on the hull, gives at max a 10 degree deflection. Although, with the DGX compass, it is virtually non-existent, compared to the Suunto compass. I insured a Halcyon tank anti slip pad, which I cut to size. Only the pressure from the straps, onto the hull, is keeping the pad in place. I may cut holes in the pads and thread the bungee straps through the pad, but have not made any decision yet.

20200714_183836.jpg 20200714_183906.jpg

Here's a video of a dive from a few years ago. I'm on the SS Viper, another buddy is on a Gavin and everyone else is on Genesis 1200s with your rover compass. Everyone on the Genesis 1200 DPVs has your compass mounted on the hull. Several of my buddies have removed the original fabric strap in favor of bungees.


I am not an engineer but I would think that the tube with your compass mount, when extended away from the hull would create excess drag. At full speed, it might even get sheared away from the hull. I just did a two hour dive where we completed a two mile in-out pattern. Granted, the navigation patter is simple but I didn't mind using my wrist compass. I "may" remove the compass from the hull, in the future.

Trim & buoyancy wise, I'm going to add a few more ounces but I'm nit picking at this point. Every DPV that I have seen sinks at depth. It might be better to have it slightly positive. If I ever need to release it will be besides me and not dragging on the bottom.

O.
 
Here's the scoop on the compass. The older batteries used lithium polymer cells that had no magnetic material in them. The WarpCore uses 18650 cells that have a steel can for the cell's casing and it is the steel cell case that is causing the "soft iron distortion" as the compass pointer is attracted to it. The best place to locate the compass on the Warp Core is between the cells and the motor, pretty much where Ouvea has it. It will still have a small amount of distortion, but most will not be able to notice it having an effect on being able to navigate underwater. Another option would be to create an extension that places it forward of the nose, but I haven't tried that.

Something else on my todo list, is to place a sheet of MU metal between the cells and compass, to see if that will shield it. Unfortunately, I have a long todo list.

Cheers,
Jon
 
Something else on my todo list, is to place a sheet of MU metal between the cells and compass, to see if that will shield it. Unfortunately, I have a long todo list.

Jon, what is MU metal?
 
https://www.shearwater.com/products/perdix-ai/

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