Submersion System for Offshore/Exposed Mussel Farms
Final Report

Cross Bay Mussel Farms Ltd.
AIMAP-2009-N01

Objective
The objective of the submersion project is to overcome restrictions placed on site selection of mussel farms by northern pack ice and shifting bay ice. The challenge for Cross Bay Mussel Farms (CBMF) was to modify existing submersion technology, and implement it in an exposed area on Newfoundland’s north east coast where Arctic and pack ice is an annual event.  A large deep water site was selected in Little North West Arm (LNWA), New Bay, Notre Dame Bay. The criteria for this site were; (1) Deep water to permit the sinking of lines beneath depth of Artic Ice; (2) Remote, to minimize safety concerns with recreational and commercial boaters, and to avoid conflict with cabin owners; and (3) Large, to address future expansion requirements, and to optimize on food supply.

Implementation of Project
On Sept 28/09 we implemented the AIMAP project. In October we began fabrication of collectors, sinkers, teflon stop blocks, and installed u-bolts in collector lines. This work continued until January 2010. Following this we prepared for submersion of the 50,000 collectors set in 2008. Farm submersion started January 06/10 and continued until March 13. Each trip was a three day duration.  Collectors had to be re-floated from bottom before re-submersion with the 600 lb sinkers. 

Lines were re-floated from July 9 – July 14/10. Normally lines would have been refloated in late spring or early summer, however, there were icebergs in the area with the potential to cause significant damage to the farm.  

Engineering report
Bridger Design Associates Limited (BDA) was contracted in June 2009 to carry out a detailed analysis of the proposed submersion system. This involved; (1) Collection of weights and volumes of all mussel farm components; (2) Collection of typical weights of mussels through their growth cycles; (3) Analysis of the net weight in water of mussel farm components plus the weights of mussels at various stages of growth; (4) Based on this analysis, development of charts to assist operators in selecting the optimum size and number of sinkers required for submersion; (5) Selection of a mussel farm monitoring system consisting of a depth sounder, side scan sounder, and a global positioning system (GPS); and (6) Redesign of the teflon stop block used to submerge the mussel lines.

Redesign of Teflon block stop
The teflon block stop used in the original block stop was redesigned. In the original design the sinker rope was locked into position by tightening (turning) a 0.5” diameter SS screw into the sinker rope to bind it against the teflon block stop. There was evidence of screw treads cutting the sinker rope during the tightening process. The redesigned stop block involved drilling a 0.5” hole through center of block, than cutting the block into two even pieces through the middle of hole. The 0.63” sinker rope is locked into position between the two halves of Teflon through the 0.5” hole than the two halve tightened with a 0.38” diameter screw inserted through the teflon on each side of the sinker rope.

Mechanical breakdowns-250hp
Throughout late fall and winter out site service vessel experienced several breakdowns with lengthy downtime while waiting for replacement parts.

Difficulty renting long liner due to Mackerel fishery
Throughout the fall and early winter we tried unsuccessfully to charter a long liner to transport sinkers to LNWA. All long liners in the local area with the required hydraulic lifting and carrying capacity to lift or move sinkers were involved in the Mackerel fishery. This caused a significant delay to starting the onsite portion of the project.

Slippage of sinker rope through the Teflon block stop
This occurred when the Teflon block was fastened to the long line and the system is submerged. The upward force exerted by the floatation resulted in anchor line slipping through the Teflon stop block causing the long line to resurface.

Solution: A temporary solution was devised whereby a short section of 3/8” rope was weaved through the strands of sinker rope directly above the Teflon block. A permanent solution would be to reduce the hole size in the Teflon block and/or to roughen the surface of the Teflon using a hot checkered metal mold. 

Over heating of stainless steel bolts
To reduce time and labour a cordless drill was used for tightening the teflon block to the sinker line. This resulted in overheating of SS bolts and nuts due to friction caused by the speed nuts were spun unto SS bolt.  This resulted in nut ceasing to the bolt before two halves of Teflon block were clamped unto sinker line. Due to the extreme cold it was difficult to operate a drill without insulated gloves, which in turn, restricted use of the variable speed necessary to reduce control by which the nuts were fastened to the bolts.

Solution: To use manual box end wrenches. During this process we experimented with lock nuts (with Teflon sleeves) and regular nuts with lock washer. Installing the lock nut was very labour intensive, and slowed the overall process. Because there was very little vibration or movement after the gear was set we determined that a regular SS nut without lock washers worked fine.

New collector long line stretch
This is normal when new long lines are first set. However, the long lines at LNWA appeared to have an abnormal amount of stretch. Some of this may have been caused by extra length of long lines (3500’). Also, different brands have different stretch factors. The extra stretch resulted in increased sagging between floats on long lines, and not enough extra long line to tightened collector line after stretching occurred. Consequences of the extra sagging or slack lines are;

• Collectors positioned approximately mid distance between floats will be in deeper water, and possibly beneath algae blooms which provide food for mussels.
• The effect of wave action on slack long lines is increased resulting in increased “drop-off” of mussels from collectors.
• Tidal influence will result in more perpendicular drift causing lines to tangle with adjacent lines.

Solution: To resolve this issue extra long line was required from the last collector to the anchor line on each end of collector long line. This allowed plenty of long line to periodically tighten collector lines. There will be very little stretch after year one.

Long line Breakage
During the sinking process two lines were broken. Upon observation the crew discovered the breaking point occurred where the U-bolts were inserted through the long lines. U-bolts were fastened to long lines with two SS plates. During windy conditions wave action caused chafing between the SS u-bolt and fastening plate, causing the long line to eventually break. 

Solution: Ensure all u-bolt plates are sanded to remove any sharp edges.

Submerge gear as soon as seed collection is complete to avoid chafing from wave action. Submerging the gear early also prevented seed losses that are normally associated with wind and wave action. This is especially important in the larger, more exposed sites, with longer fetch and larger waves.

Difficulty retrieving sinker line during the spring re-floatation phase
Sinker lines were cut short; therefore we were actually lifting the next sinker on each adjacent line (four sinkers) to be released from long line.  The 50’ depth of the collector long line should have been taken into consideration before determining the sinker line length.

Solution: Sinker line length should have been determined after long line was submerged.
Ensure that sinker lines are long enough to return to the surface before sinkers are lifted from the bottom.
 
Bottom Gradient
Steep bottom gradient in certain areas of site caused sinkers to slide into deeper water after installation. This will also result in longline being closer to the adjacent longline which will increase the possibility of two lines tangling with each other. As soon as the sinker moved from its original position on the bottom to deeper water a longer anchor line was required to reach the surface during the floatation phase.

Solution: Check marine chart and conduct depth sounding to determine bottom gradient. Haul sinker from bottom a few meters, and let free fall to bottom. If it doesn’t slide into deeper water after free fall it should remain in position.  If the site bottom consists mostly of steep gradient it is questionable whether the site is an ideal site for this type of submersion technology. Increase length of anchor line on all sinkers to ensure there is enough line to reach surface. Extra length can be determined by paying close attention to the bottom profile as line is submerged.

Scheduling Challenges
Due to long liner rental (mackerel fishery) and floatation issues (defective floats) deployment of sinkers were delayed until January 2010 and not completed until March, 2010. However, we were fortunate the arctic ice field did not extend south as far as the north east coast this past winter. This was a rare occurrence.

We took six-eight months to finalize the installation of the side scan sonar. This was caused by difficulty getting technical help from the supplier M. Francis Kelly (Cansel). We were also waiting several months for Cansel to receive adapter cables that were necessary to complete the wiring from transducers to the electrical display unit.

Fall and winter 2010 were exceptionally stormy. Some trips to site had to be delayed for weeks.

Floatation Issues
Submersion project was delayed two months as a result of defective floatation purchased from Go Deep International (Fredericton, New Brunswick). Also, floatation from Enterprise Shippagen, (Shippagen, New Brunswick) was delayed due to an employee accident at the fabrication plant. The plant was shut down for several days until an investigation was completed.

Floatation purchased from Go Deep International was fabricated by Everest Plastik (Tracadie-Sheila, New Brunswick). We became aware of the problem when off-loading from the delivery truck on Dec 14/09. Two floats shattered (exploded) upon contact with the ground when off-loading. On Jan 05/10 we tested 80 floats by dropping each float from 14’ elevation (roof of shed) and 22 floats exploded upon contact. The following day the tested floats were loaded aboard a pickup truck and off-loaded at the wharf site. Six floats that already passed the initial test from the shed roof broke when tossed from the truck to the wharf. The remaining floats were loaded aboard the Long liner, and used for the submersion project. Our concern was; will the floats implode at depths as easily as they exploded at atmospheric pressure. The quality of the whole load was questionable. However, due to the lateness of the season, time required to submerge the collector lines, and fear that the arctic ice would soon be entering NDB, the remainder of floats that passed the drop test was used in the submersion project.

The Tracadie plant was shutdown on Dec 14, and an investigation was started to determine why the floats were defective. The plant has three molds and suspected the problem might be caused by one mold. Some adjustments were made and the plant went back into production. We were guaranteed the problem had been corrected. Another tractor trailer load was ordered and arrived on January 09/10. The first float removed from the truck was defective. We removed a total of 35 floats with 5 floats being defective. All floats were loaded back on the truck along with the shattered remains of defective floats from previous load. Go Deep International was notified that the truck load of floats were been returned to New Brunswick.

Following this we ordered floats from Enterprise Shippagan on Jan10/10, and were told that the floats were already fabricated and ready for shipment.  When the floats did not arrive within a few days, we phoned Shippagen to be told he had made a mistake, and there were no floats ready for shipment.  A shipment of floats did arrive on Jan 21/10, however, instead of CBMF receiving a full load, as promised, the shipment was split with two other growers leaving CBMF with only 115 floats, which was not enough for a trip to LNWA. Finally on Jan 30/10 a full load did arrive. When weather permitted during Feb and early March, ten sinkers were set in place and collectors were submerged.

Variables of the Submersion System
One of the major issues with the design and development of the submersion system has been overcoming/resolving the variables in the system – floatation, system weights and mussel growth.  The system designed by Alvin Hodder was for sites with a depth between 40 and 60 feet of water.  CBMF’s sites are 180 feet plus and the issue of achieving balance between amount of floatation, amount of systems weights, and extra weight from mussel growth became more difficult. As 40 – 60 feet of water would not be an issue for pressurized floats and the potential for failure, tripling the depth does pose a problem for pressurized floats (depth shrinkage), especially when they are dragged down in the water with the increase in weight of the mussels, etc.  As stated earlier in this report, floatation failure has been an issue before the floats were deployed.  Likewise, failure of the floats in a submersion system has been an issue as well.  Given that the latter failures were at the expense of the company and could not be determined as a fault of the float design at the time, the former failures were returned to the manufacturer and CBMF did not have to pay for the floats.  Resolving the variable problem was compounded by the loss of the company’s market for mussels, and as a result the company was not able to maintain a monitoring program to check on the submersion systems.

Affects of Recession/Marketing Issues
The impact of the recession really paralyzed CBMF during the fall of 2010, through the 2011 year and into the 2012 year.  With the loss of mussel sales and markets, it became increasingly difficult to maintain our farm sites.  In Newfoundland & Labrador, there are three or four major mussel producers who supply the mussel market and attached to them are other growing operations such as ourselves.  Where the major mussel producers are growers themselves, they of course fill most of the orders they have with their own mussels.  It is only when they are unable to fill the orders that they rely on the other growing operations to fill the orders.  Hence, the medium to small growers are at the mercy of the larger growing operations.

Any income from SRED, GST claims, or minimal sales was utilized to pay CBMF’s creditors which left very little cash flow to purchase fuel or maintain equipment and gear.  Without the ability to maintain equipment and gear, CBMF was unable to check the experimental submersion systems to determine if the systems required additional floatation.

Impact of Arctic Ice – Winter/Spring of 2011
March 2011-Continuous pressure from the N/E – N/W winds throughout February shifted the pack ice from the Hudson Bay area, up the Labrador coast and, threatened to impact mussel farms along the North East Coast. Without funds to apply the submersion technology we had to make the difficult decision to cut floats from the collectors at LNWA submersion site. This resulted in all collectors sinking to the bottom.

The alternative to this was; to leave gear at the surface, and risk having it destroyed by northern ice. In this scenario LNWA, New Bay, and a significant portion of the North East coast would become a navigational hazard, due to tangled collector rope and floats being dragged out of LNWA by the shifting ice field. In addition to potentially causing serious accidents to mariners, CBMF would be guilty of serious legal violations.

Due to cash flow shortage the site remained submerged from spring of 2011 to the present. During winter of 2011/12, parts of the site started to re-float due to star fish predation. Several site visits were made to re-submerge long lines by removing floats. This was done to due to the threat of pack ice lying north of Notre Dame Bay.