Gavin vs. Silent Submersion
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PfcAJ
Contributor
I used to own a Gavin. My experience with SS has been limited to the models Rodney has sent for the benchmark, which for your specs would be the UV-18 and UV-26.
Empirical data:
(summary) The SS will go further than the Gavin, and do it faster than the Gavin, on the same battery power.
(expansion) The last test we had several Gavins available. We thrust tested them all, and used the fastest one. When we got them both in the water, the SS was faster with significantly less draw in watts, and sounded nicer, too.
The only lead-acid failures in the Benchmark were Gavins.
Personal experience:
My Gavin had issues. the batteries would occasionally slip unless I tightened the plates so hard I thought the battery cases would crack. At the time I thought it was awesome (compared to a Mk5) but I grew to regard it as a heavy evil thing that demanded fixing.
Plunk a SS down next to any Gavin, and it's obvious which is better. The bulkheads keep the batteries from shifting, the wiring is quality and well laid-out, it's just quality. The Gavin seems agricultural when it's sitting next to the SS.
I can't address the market prices. I know if I was buying one used I'd willingly pay a premium for the SS over the Gavin.
My experience on SS is limited, though, maybe 16-18 miles or so.
All the best, James
Empirical data:
(summary) The SS will go further than the Gavin, and do it faster than the Gavin, on the same battery power.
(expansion) The last test we had several Gavins available. We thrust tested them all, and used the fastest one. When we got them both in the water, the SS was faster with significantly less draw in watts, and sounded nicer, too.
The only lead-acid failures in the Benchmark were Gavins.
Personal experience:
My Gavin had issues. the batteries would occasionally slip unless I tightened the plates so hard I thought the battery cases would crack. At the time I thought it was awesome (compared to a Mk5) but I grew to regard it as a heavy evil thing that demanded fixing.
Plunk a SS down next to any Gavin, and it's obvious which is better. The bulkheads keep the batteries from shifting, the wiring is quality and well laid-out, it's just quality. The Gavin seems agricultural when it's sitting next to the SS.
I can't address the market prices. I know if I was buying one used I'd willingly pay a premium for the SS over the Gavin.
My experience on SS is limited, though, maybe 16-18 miles or so.
All the best, James
ucfdiver
Contributor
James,
Did you place any rubber under your batteries on the Gavin? That's what I had to do for mine to keep them from slipping.
One gripe that I have with my Gavin is that the battery wiring is one solid cable rather than stranded. I've never fully understood the logic there, since stranded wire typically has more throughput.
Did you place any rubber under your batteries on the Gavin? That's what I had to do for mine to keep them from slipping.
One gripe that I have with my Gavin is that the battery wiring is one solid cable rather than stranded. I've never fully understood the logic there, since stranded wire typically has more throughput.
OP
The SS motor is made by SS, but it is very similar in terms of dimensions and things to the Oceanic motors. It opens up just like the Oceanic, dissassembles like the Oceanic. On this, I'm fairly certain, but there might be small differences. I wouldn't know, because I've never heard of anyone needing to work on their SS motor.
To be fair, I don't know of many people who need to work on Oceanic motors, either.
Rodney uses RTV silicone on the shaft seal, so it's more work to remove than the seal on an X, I'm not sure if the seal on the Gavin is glued in or not.
The brushes on the SS motor are way better than Gavin brushes. They are spot welded, not soldered, for a more reliable and better conducting connection. Instead of sending electricity one way around the brush board, they send it both ways. The brushes wear very little compared to Gavin brushes. Rodney told me about a company that dives with the scooters daily. They would send in the scooters to be serviced on some schedule, perhaps a year or 18 months, I forget. The Oceanic motors needed to be blown out and maybe the brushes replaced. The SS motors, at the same time frame, had almost no carbon dust at all.
I had a problem with an Oceanic motor that had more pull on one side of the magnet housing, so it pulled the armature to one side, and eventually pulled enough to start dragging ont he magnets, wearing down the armature. I believe this happened because the Oceanic motors, which use a magnet housing formed from rolled steel, can be slightly out of round, allowing for one magnet to be closer to the armature than the other side. SS motors have a magnet housing cut from a tube, so it's much closer to perfectly round.
Rodney claims the coating on the SS motors is more robust than the Oceanic coating as well, showed me two exposed to saltwater, and the Oceanic one was severely pitted while the SS one was only minorly affected.
PfcAJ, what have you worked on on your Gavin? I think you could put other batteries in an SS if you wanted to, but the Genesis batteries seem to have a pretty good track record. Rodney claims they are much more consistent in weight than other batteries, making balancing the scooter on a production line easier: no need to custom weight every scooter.
To be fair, I don't know of many people who need to work on Oceanic motors, either.
Rodney uses RTV silicone on the shaft seal, so it's more work to remove than the seal on an X, I'm not sure if the seal on the Gavin is glued in or not.
The brushes on the SS motor are way better than Gavin brushes. They are spot welded, not soldered, for a more reliable and better conducting connection. Instead of sending electricity one way around the brush board, they send it both ways. The brushes wear very little compared to Gavin brushes. Rodney told me about a company that dives with the scooters daily. They would send in the scooters to be serviced on some schedule, perhaps a year or 18 months, I forget. The Oceanic motors needed to be blown out and maybe the brushes replaced. The SS motors, at the same time frame, had almost no carbon dust at all.
I had a problem with an Oceanic motor that had more pull on one side of the magnet housing, so it pulled the armature to one side, and eventually pulled enough to start dragging ont he magnets, wearing down the armature. I believe this happened because the Oceanic motors, which use a magnet housing formed from rolled steel, can be slightly out of round, allowing for one magnet to be closer to the armature than the other side. SS motors have a magnet housing cut from a tube, so it's much closer to perfectly round.
Rodney claims the coating on the SS motors is more robust than the Oceanic coating as well, showed me two exposed to saltwater, and the Oceanic one was severely pitted while the SS one was only minorly affected.
PfcAJ, what have you worked on on your Gavin? I think you could put other batteries in an SS if you wanted to, but the Genesis batteries seem to have a pretty good track record. Rodney claims they are much more consistent in weight than other batteries, making balancing the scooter on a production line easier: no need to custom weight every scooter.
ucfdiver
Contributor
Genesis batteries are expensive as ****, almost double what the gavin power sonic's cost.
I'm about 99% sure the Gavin shaft seals use silicon.
I'm about 99% sure the Gavin shaft seals use silicon.
cool_hardware52
Contributor
To start with the Lithium Ion batteries don't weigh all that much.
Typical lead acid battery will provide about 10-12 watt hours per lbs.
18 amphours @ 24 volts is 432 watthours. Such an SLA battery will weigh ~ 36 lbs.
The 1150 watthour packs we build for the Dive X Fury's are ~14 lbs. (~82 watthours per lbs.)
Lets say the SLA pack is offset by 2 inches from center line. That's 72 inch lbs.
To achieve the same moment with our lithium pack would require an offset of 5+"
The X hulls are nominally 8" in diameter. They would have to be *18"* in diameter allow the same results.
Tobin
OP
Tobin, I think he was talking about attaching a lead plate to one side of the square battery to help offset the torque.
I know the Magnus comes with a steel plate for the nose to provide extra weight to balance the scooter...
but do any scooters come with a weight that is asymmetrical, to help offset torque? SLA's can do it by offsetting the heavy-as-all-get-out batteries, but other technologies cannot.
I know the Magnus comes with a steel plate for the nose to provide extra weight to balance the scooter...
but do any scooters come with a weight that is asymmetrical, to help offset torque? SLA's can do it by offsetting the heavy-as-all-get-out batteries, but other technologies cannot.
ucfdiver
Contributor
Think you misunderstood (or I didn't say what I meant to say).
If the pack was square, or even semi circle, there would be a way to make room for a dense weight such as lead to counter balance the scooter, no? My main complaint with these scooters is that they all want to rotate counter clockwise while driving them.
For some reason the Magnus didn't really do this...
cool_hardware52
Contributor
I have the ballast in my X's mounted asymmetrically.
Not that hard to do. Weight pouches that velcro to the interior. Lots of options on where to mount them.
To understand *why* longer smaller diameter tubes are a benefit for high powered scooters that use lighter batteries requires a more complete understanding of the horizontal trim requirements.
For example consider what would happen if you increased the tube diameter by only two inches but left the length the same.
Tobin
Not that hard to do. Weight pouches that velcro to the interior. Lots of options on where to mount them.
To understand *why* longer smaller diameter tubes are a benefit for high powered scooters that use lighter batteries requires a more complete understanding of the horizontal trim requirements.
For example consider what would happen if you increased the tube diameter by only two inches but left the length the same.
Tobin
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