Specialty Products for Fish and Shellfish Pots and Traps

Galvanic Timed Releases

Galvanic Timed Releases (GTR’s) are reliable underwater timing devices. They are also known as POP-UPS. The patented design of the GTR uses two dissimilar metals that corrode at a predictable rate. GTR’s must be used in salt water. Their corrosion rate depends on the water’s salinity and temperature at the depth being used.

10% Surcharge for less than full bag quantities
$40 Minimum order size

Time Model Price Per Unit Price Per 50 gtrs
1 day A3 – A6 $1.60 $80.00
2 day B1 – B6 $1.70 $85.00
3 day C1 – C6 $1.80 $90.00
4 day D1 – D8 $1.90 $95.00
5 day E1 – E5 $2.00 $100.00
5 day E6 – E8 $2.05 $102.50
6 day F1 – F5 $2.05 $102.50
6 day F6 – F8 $2.15 $107.50
7 day G1 – G6 $2.10 $105.00
7 day G7 – G9 $2.40 $120.00

NOTE: Timers available for 10 & 14 day can be custom made.

ACCURACY – GTR’s release time varies over the temperature range stated in the chart below. One day releases have a variability of 6 hours between left and right hash marks. All other time durations have a variability of 12 hours between hash marks. The hash mark on the left represents the actual release time at the temperature above the hash mark. For instance, an A4 will release at 24 hours at 53F. At the right hash mark, 59F, it will release at 18 hr. For a 2 day B4, the GTR will release at 48 hr. at 46F and at 36 hr. for the temp above the right hash mark, 57F. For temperatures between the hash marks, release times can be approximated. In the event GTR release timing is longer than desired, the releases can be “burned off” by pre-soaking them in salt water to corrode off the extra hours. Do not place a full bag of releases in a small bucket of salt water, as the chemical reaction will increase the water temperature thereby altering the corrosion rate.


Applications For Galvanic Timers

gtrbuoySUBMERGING A BUOY UNDERWATER to avoid traffic, detection by other fishermen, or to prevent poaching. Numerous methods are used to rig up the line and buoy. Care must be taken in rigging up the coiled line to prevent any tangles when the GTR releases the line and buoy. Check local regulations to insure compliance.

is achieved by using GTR’s to activate an escape mechanism such as an escape door or escape panel. The use of GTR’s to prevent ghost-fishing pots offers a “time certain” method that allows visual inspection. This is not available with untreated cotton twine or untreated metal hog rings.

gtrlostgearGEAR RETRIEVING SYSTEMS – GTR’s are used as timing devices to release a retrieval line and hard plastic buoy. Such systems can be used on pot gear as well as longline and gillnet gear.

gtrbaitbagTIMED BAIT RELEASE CONTAINERS can be activated using GTR’s. They allow the pot to be rebaited without pulling the pot. This is especially useful on longer soaks caused by delivery schedules or bad weather. They can also be used in areas where sea lice are a problem. This drawing is conceptual and was made with plumbing pipe and fittings along with a bait jar. The jar would not be pressure proof but would allow the salted or frozen bait to be contained out of the current until the GTR releases.

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