I wanted to get another dive in on the rebreather this weekend after making some adjustments however the thought of driving down to Hathaway’s on the Cape or driving 7 hours (roundtrip) up to Vermont did not really appeal to me so I opted to check the tides for Peirce Island in Portsmouth, NH.
Peirce Island
Peirce Island is a dive site on the Piscataqua River which a 12-mile-long (19 km) tidal river forming the boundary New Hampshire and Maine. Due to the strong currents and tidal flow in the river this dive can only be done during a slack tide window. This site can be really pretty when the visibility is good. The wall which gets down to 80ft is covered in frilled anemones. It is actually one of my favorite shore dives in New England in the winter when conditions are good but I don’t really dive it that often since the slack window times don’t always line up for when I want to dive.
The Piscataqua is considered the second fastest flowing river in the United States, averaging almost 3 knots on the incoming tide and 4 on the ebb. It is not a place you want to mis-time the slack window. I consider it a relatively “advanced” shore dive site due to the currents and potential depth but to be honest the navigation is easy, the entry is easier and the dive itself is pretty straight forward. The takeaway I tell everyone is make sure you double check the slack tides and check surface currents before entering.
These drone images and surface images of the dive site are from Timur. Credit to images goes to him. His blog is https://todivetoday.com/
Rebreather Tweaks
I figured it would be nice to get a little more depth on the rebreather this weekend although I was hoping to avoid salt water because I hate rinsing gear in the cold.
I added another 3lbs because were were diving in salt and I knew I was already slightly overweighted for freshwater. I’ll need to go back and remove this weight before testing again in fresh water. I ended up swapping the LP hose on the oxygen reg first stage to a 40″ hose which was far better. I believe this is what most people use on a Sidewinders or Geminis. This also solved the leak I had the other day from the LPI fitting.
I still have not touched the Oxygen MAV or Diluent MAV hoses lengths yet as I wanted to do some additional testing before moving them around. I did remove the 90 degree fitting on the diluent side because I found it unnecessary.
The last change I made was I switched the bungees on the canisters to clip around my chest rather than attach to my harness d-rings. This seems to pull canisters in little more and unclutters up my chest d-rings but of course it’s one more thing to connect in the water. Otherwise these were the only changes that I’ve made to the rebreather.
Actual Dive
We ended up having a fairly large group of 9 divers at Peirce Island which is not really a big deal since it’s a big dive site. The predicted slack tide was 1:09pm and we entered the water around 12:30pm. Our slack timing on this dive was good however due to the full moon the water and current were higher than normal. We entered the water slightly before predicted slack window (as usual) but by the time we exited the water the current was ripping.
The visibility was about 10-15ft with lots of particulates in the water column. This is sort of average but I was expecting and hoping for it to be better due to lack of rainfall. The water temperature was 47 degrees Fahrenheit. It’s still a bit early for the large population of nudibranchs that are usually present in the winter although some were there.
The wall itself seems to have a lot less anemones than it usually does. In past years/dives, it is usually completely covered.
Overall the rebreather worked really well. The salt water weighting was good and everything on the unit worked perfect. The new oxygen LP hose length was much better and did not pull on the oxygen bottle. I’m still not going to touch the diluent and oxygen MAV hose lengths as I want to do a few more adjustments. Still in the honeymoon phase here and I hate changing multiple things when testing new equipment.
I still hate how “busy” everything is with the wing inflator, oxygen MAV, diluent MAV, drysuit inflator and now canister bungees going across the chest. I’m sure I’ll get used to it but I think maybe switching to a dual gas MAV or moving the diluent MAV to the left shoulder may help a little it.
We kept our dive to 60 minutes and even that was a bit of a struggle due to tide window. We probably should have cut the dive 5-10 minutes shorter or went in 5-10 minutes earlier to compensate. The beginning of the dive had us pulling along the bottom and the end of the dive had us pulling ourselves along the rocks to get back to shore. It felt a little bit like Florida river cave diving although not as warm!
Great writeup, Mike, thanks for sharing.