Folks just wanted to share what I’ve been doing with the Sofirn SD-05. Not your usual review since I haven’t gotten everything setup to do more scientific/systematic testing. This is more for fun
First some spec’s.
Many of you know this diving light already:
- 21700 Diving flashlight XHP 50.2
- Magnetic switch
- Off - low, medium, high (mine on a fully charged Sofirn battery 4.2V texas Ace Lumen Tube - 2236 lumens.)
- dual gaskets at the head and tail caps, extra thick front glass (didn’t measure with calipers)
Kit came with charger, battery and lanyard extra gaskets.
For this test I decided to drop it down for a little crabbing adventure. Depths at 60-150+ft for 1-1.5 hour soak time.
- Setup on crab pot
- from a friends GoPro
Construction is very good and even at 150ft+ ft deep drop for 1.5 hours there was not a drop of moisture or condensation inside. It was completely dry and according to the video kept on going in the cold frigid waters of Puget Sound (at depth in the upper 40’s to low 50’s F this time of year). Since it landed on a muddy bottom the switch did get a little gritty feeling afterwards. After a good rinse, soak in fresh water with some silicon lube it was fine. I do rinse/soak all my equipment after using in salt water, so will do so for the longevity tests for this light. Too bad shrimping season is over or I’d be sending this down to 250ft depths. Maybe next year. Their stated rating on Amazon.com is 100m or apprx 328 ft so I have a ways to go to push its limits. If it gets destroyed one of these days I’ll be sure to report what depth it made it to. However I won’t purposely destroy it.
I wore 7mm neoprene gloves to handle the crabs, and avoid jelly fish tentacles that get pulled up with the pots and switching the light on/off in various modes was very simple. Never had a problem. So far this light has yielded a few more crabs at deeper depths. On shallower depths the light from the sun is still very visible as you can see in the video, so it didn’t really affect the catch. In the winter time, squids are definitely attracted by light so hope to catch some good footage of them with the light.
Plans are in place this year for putting it down with the downrigger ball while salmon fishing. Then in winter - squid jigging when water temperatures go really low but depths are not so deep. If I can get another one at a discount, may look to put a UV LED in there in place of the 50.2 to see how that lights up under water. Does anyone know of a UV bulb that is the same 50/50 footprint? May do a tear down when that is done.
i vote this as the best all time use for a flashlight, that was an awesome video, thanks for sharing.
i had no idea there was so much activity down there; i guess there is a one way door to catch the big guys and let the little ones go. They looked huge, how much do the big ones weigh?
The large Dungeness crabs are about 7.25” end to end at just over 2lb, smaller legal size here is about 6.5” end to end (legal limit is 6.25 but just inside the widest part of the crab shell) and usually weighs 1.5-1.7lb each. We get the occasional dog fish/flounder in the pot and seals sometimes move them away (we lose the pot) as well.
The traps have a one way door and here in the Puget Sound, we need to send back the females and anything under 6.25”. Winter crabs are heavier. I know there are a few anglers and fishermen here, so thought I’d share.
Thank you for posting. I like a review with run time graph, thermal, specs, table. But a post with a practical use for my flashlight. Hell yeah.
I did got the SD05 just because I like the sime UI and magnetic ring.
Might gonna try this one day.
So sometimes a seal will move the whole pot so far away that you can’t find it? Yikes you would lose your camera and light.
i guess the little flounder were attracted to the crumbs falling off the table as the big crabs were busy pulling, shredding and fighting over the bait.
It looked like they were attacking the camera after the meal and they couldn’t get out of the box.
There are buoy’s so if the seal didn’t drag the pot to deep waters we can usually spot and retrieve them. We know some officers at the WDFW (Washington Department Fish and Wildlife) that regularly haul hundreds of derelict pots (both recreational and commercial) out of the sound every year. The ones with names and addresses get returned to owners. Sea lions would literally tear apart a recreational crab trap. Last time we pulled up a derelict commercial pot and it had several crab stuck in it for quite some time. It burnt the 30A fuse on the recreational pot puller we use on the boat and took 3 people to haul in. Our lines got snagged on their submerged lines full of barnacles etc,.
Now to figure out how to tie the flashlight and camera to a down rigger setup.
Down rigger - we use it for salmon fishing but it can be used for other types of fish. It keeps your baits and flashers in deeper waters while trolling. Otherwise it becomes difficult for us to keep the bait under water while the boat is moving and it tries to float up. we tend to use 15lb lead weights and clip the bait on a leader line to it, when the fish strikes, the bait rig snaps off the downrigger and then you free reel in the fish without a 15lb ball attached to it. It allows you to cover more area than sitting in place and jigging. Its quite fun. Diagram below we do #4 & #5.
Basically I need to tie the flashlight somewhere near the 15lb ball facing rearward along with the camera pointed in the right direction. Typically moving anywhere from 1.5-2.5 mph depending on the kind of fish we are targeting. The speed plus the currents can make the flashlight and camera a challenge
i was thinking maybe a clear teardrop shape camera holder would cause it to always point opposite to the trolling direction. It could have a truncated tail with a flat polished end for clear vision with low distortion.
Their stated rating on Amazon.com is 100m or apprx 328 ft so I have a ways to go to push its limits. 
If it gets destroyed one of these days I’ll be sure to report what depth it made it to. However I won’t purposely destroy it.
