Waterproof Sailing and Marine Bags: The 500-Hour Salt Spec

Deck Bag, Chart Tube, Winch Roll and Liferaft Bag: Four Families

Marine storage is four products, not one, and the four are used in four different parts of a boat by four different people for four different reasons. A deck bag lives in the cockpit or on the coachroof and it holds the things a crew reaches for constantly. A chart tube protects paper or a tablet and it has to stay rigid when it is wet, because a soft chart tube will not slide into its berth. A winch roll holds tools that are sharp, greasy and heavy. A liferaft or grab bag is a safety product and it is specified by what has to come out of it first.

The commercial structure of the category follows from that. The deck bag is the volume product and it is sold through chandlers and through boat builders as an accessory. The chart tube is the low-volume specialist item with the best margin. The winch roll is a maintenance product bought by owners and by yards. The grab bag is the one that is bought on trust, and it is the product that decides whether a brand is credible in the marine market at all. We recommend a brand entering the market lead with the deck bag and the winch roll.

There is one requirement common to all five and it is not the waterproofing. Every product on a boat that is not attached to the boat will go over the side, and a bag that goes over the side is gone. Attachment is therefore a primary specification in this category and not an accessory, and we build an attachment point into every marine product we make, sized for a clip rather than for a hook. The formats we build across all five are on our products page.

Salt Spray Exposure and What It Does to Marine Bags

Salt does its damage mechanically, not chemically, and that distinction changes what a supplier should do about it. Seawater itself is not particularly aggressive to a polyester or a TPU laminate. What destroys a marine bag is the salt crystal that remains when a film of seawater dries on the fabric, because that crystal is harder than the coating it sits on and it is worked into the fabric at every fold, every flex and every movement of the bag against a deck.

The three places this shows up are the folds, the hardware and the threads. At a fold, a crystal acts as an abrasive and it cuts the coating from the inside as the fabric flexes. On hardware, a plated metal component corrodes and then either seizes or fractures, and it does so at the moment it is being used. On thread, an untreated polyester thread wicks salt water into a seam and holds it there, which is how a marine seam rots from the inside while the fabric around it is still sound.

• Use a bonded or a laminated construction at every fold, so a crystal cannot work between a coating and its base fabric
• Use acetal or nylon for every clip, buckle and slider, and no plated metal anywhere on the product
• Use a bonded polyester thread with a low wick rate, and a bonded seam tape rather than an adhesive one
• Fit a drain at the lowest point of every external pocket, because a pocket holding seawater is a salt factory
• Specify a rinse path at the base of every zip run, so a flush with fresh water actually removes the salt

The rinse path is the most useful of those and it is the one most often omitted. A seawater-exposed zip collects salt in the coil, and a crew member who flushes the bag with a fresh-water hose will clean the face fabric and leave the salt in the coil, because the coil is shielded. A 6 mm channel at the base of the zip run lets the flush water pass through the coil and carry the salt out. It costs nothing to include and it roughly doubles the service life of a marine zip.

The performance consequence of salt is measured, not assumed. After salt spray exposure to the method in ISO 9227, we re-measure the hydrostatic head to ISO 811 and we check coating adhesion and abrasion to ASTM D751 on the same lot. A laminate that holds 20,000 mm new and 8,000 mm after exposure is not a marine fabric, and this is the reason we do not approve a material for marine use on its new-condition data sheet alone.

UV Load on Deck and the Reflective Surface Problem

Ultraviolet radiation is the harder problem in this category, and it is harder in the marine environment than anywhere else for a specific reason: the boat is a curved mirror. A bag on a coachroof or in a cockpit is receiving direct sun from above and reflected sun from the water and from the brightwork around it, and the combined dose is roughly double what the same bag would receive on land. A coating that survives a season on a hiking pack can fail in a single summer at sea.

The failure mode is a specific one and it is worth describing because it is not obvious from a sample. UV attacks the coating before it visibly attacks the base fabric, and the sequence is: the face chalks, the coating loses its plasticiser or its polymer integrity, and then the coating cracks at a fold. Once the coating has cracked, the water column is gone even though the fabric still looks intact. A bag that looks acceptable at the end of a season can have lost most of its waterproofness by then.

The third and the fifth rows are the two that matter and they are the reason we will not approve a marine fabric on a data sheet. A supplier who tests a fabric for UV resistance is usually measuring the colour change of the dyed fabric, which is a selling question rather than a functional one. We measure what happens to the coating's adhesion and to the water column after exposure, because a bag that still looks the right colour and no longer keeps water out has failed.

Two construction measures follow from this and they cost nothing. The first is that the sun-facing panel of a marine bag is the one that needs the higher specification, so on a deck bag we use the heavier denier and the better UV package on the lid and the front face and a lighter fabric on the shaded sides. The second is that a light-coloured shell reflects more of the load than a dark one, and we recommend a light or a mid colour for any bag that lives permanently on deck. A dark bag on a coachroof in the tropics has a short life regardless of its fabric.

The 500-Hour Salt Spray and UV Sequence

We test the two exposures together rather than separately, because that is what the environment does. A bag on a boat is sprayed, dried in the sun, sprayed again and dried again, hundreds of times a season, and the combined attack is worse than either on its own. Salt crystal abrades a coating that UV has already weakened, and UV penetrates a surface that salt has already scored. A test that exposes to salt and then to UV in two separate stages will pass a material that fails in service.

The alternating 500-hour cycle

1. The finished sample, not a fabric swatch, is mounted on a rack in its working orientation with its hardware fitted
2. Stage one: 4 hours of salt spray exposure to the method in ISO 9227, at the standard concentration and temperature
3. Stage two: 4 hours of accelerated UV exposure, with the sun-facing panel presented to the source
4. Stage three: 1 hour of drying at 40 degrees C, then the sample is physically flexed at every fold and cycled at every closure
5. The three stages are repeated for a total of 500 exposure hours, which is what a hard season at sea looks like
6. At 250 and at 500 hours the hydrostatic head is re-measured to ISO 811 and abrasion is recorded to ASTM D751

The flexing step at the end of each cycle is what makes the sequence predictive, and it is the step a supplier with a salt chamber usually omits. A sample that is sprayed and then left still will show you the chemical effect of salt and almost none of its mechanical effect, and the mechanical effect is the one that destroys the bag. We flex every fold and we cycle every closure and every buckle 500 times over the sequence, because a closure that will not move after a season in a cockpit is a failure regardless of what the fabric has done.

The acceptance we hold at 500 hours is a retained hydrostatic head of 20,000 mm or better on the shell, no cracking at any fold, and a fully functional closure and hardware set. A sample that reaches 500 hours on the fabric but loses a buckle or a slider at 300 hours is a fail, and we report the two separately rather than averaging them. The reason is simple: the fabric result tells a buyer how long the bag will keep water out, and the hardware result tells them how long the bag will still work, and those are different questions with different answers.

Shell Fabric and Coating for Marine Bags

Marine shells are chosen for a specific combination that no other category needs in the same proportions: high water column, high UV stability, high tear strength at a fold, and a surface that does not hold salt. Two constructions meet it. A 600D or 840D TPU-laminated polyester or nylon at 20,000 mm+ is the default and the one we recommend for every product that lives on deck. A PVC-coated scrim is an option for lazarette and locker storage where UV is not a factor and where a very high abrasion resistance is wanted, and it is the one we use for a winch roll.

The reason TPU wins on deck is the one already described: it does not depend on a plasticiser that UV will drive out and cold will stiffen. A PVC-coated scrim of the same weight will match it for abrasion and for price, and it will lose its coating integrity in a season of direct sun over water. For a product stored in a dark locker, that disadvantage does not apply, and the PVC construction then wins on its abrasion and its weldability. We make that split in writing on every marine quotation.

• 600D TPU-laminated polyester, 20,000 mm+, for a cockpit or deck bag, the default for the category
• 840D TPU-laminated nylon, 20,000 mm+, for a liferaft or grab bag and for anything with a tie-down load
• PVC-coated 500D or 1000D scrim, 10,000 mm, for a winch roll, a tool storage product and a lazarette bag
• A UV-stabilised outer coating, verified by the 500-hour sequence before a fabric is approved for marine use
• A PFC-free durable water repellent finish on the face, verified at 90-100 spray rating under AATCC 22 when new

One construction requirement is common to all four and it is the one that most affects service life: the seams on a marine bag that lives on deck are welded wherever the geometry allows. A taped seam depends on an adhesive that UV, salt and heat cycling will attack, and a marine bag is the worst possible environment for an adhesive bond. An RF weld on a TPU laminate has no adhesive and no needle holes, and on a 600D laminate the result is stronger than the fabric on either side. We reserve a taped seam for the internal junctions on a complex shape and we say so on the spec sheet.

Hardware Corrosion and the Acetal Rule

Hardware is where a marine product fails earliest and most visibly, and the rule that prevents it is simple enough to state in one line: no plated metal anywhere on the product. Plated zamak, plated steel and even a plated brass slider will corrode in a salt atmosphere, and the corrosion is not cosmetic. A corroded buckle seizes and then fractures under load, a corroded slider stops tracking and then jams, and a corroded rivet stains the fabric and then lets go. In every case the failure happens while the product is being used.

We use acetal for every clip, buckle and cord lock, nylon for any webbing-adjacent component, and marine-grade 316 stainless only where a brief requires a metal ring or a shackle and where the client accepts the cost. Acetal is the right default because it does not corrode, it does not stiffen badly in the cold, and it holds its dimensions in a wet environment, which a cast nylon component does not always do. The colour stability of acetal in UV is also considerably better than a plated finish, which loses its plating first and its substrate second.

The cord lock row deserves the note, because the failure sequence is instructive and it is not what people expect. The body of a plated cord lock corrodes slowly and visibly, but the spring inside it corrodes first, and a cord lock with a seized spring will not release the cord, which means a bag that cannot be opened. That is a functional failure caused by a hidden component, and it is the reason we either use an acetal body with a 316 stainless spring or we remove the cord lock from the design entirely in favour of a webbing and cam arrangement.

The practical advice we give a crew and a brand is the same and it costs nothing to follow: rinse the hardware with fresh water, not the whole bag. A 10-second flush of the buckles, the sliders and the cord locks after a passage removes the salt that does the damage, and it is far more effective than rinsing the fabric, because the fabric is not where the failure happens. We print that instruction on the care card that goes with every marine product, alongside the instruction to dry the bag open rather than closed.

Closure Performance in a Following Sea

A closure on a sailing bag has to work in conditions no other category produces: the bag is wet, the hands are wet, the boat is heeled and moving, and the user is holding on with one hand. A closure that needs two hands and a flat surface is not usable at sea, and it will be left open, which is how a deck bag fills. We therefore specify marine closures on access time and on one-hand operation, and we test them on a heeling rig rather than on a bench.

The three closures that work are a three-fold roll-top, a moulded toothed-seal zip with a stiffener and a cover, and a webbing strap with an acetal cam buckle. The one that does not work is a storm flap over a standard coil zip, because a flap has to be lifted and held while the zip is pulled, which takes two hands and a stable surface. We use a roll-top as the default on anything over 10 L and a cam buckle on anything under that, and we state the access time on the spec sheet.

• Three-fold roll-top on anything over 10 L, four folds on a liferaft or grab bag, operable with one hand on a heeled deck
• Moulded toothed-seal zip with a stiffener behind the run and a cover flap, for access-critical products
• Webbing strap with an acetal cam buckle on anything under 10 L, at 2-3 seconds one-handed
• A 6 mm rinse channel at the base of every zip run, so a fresh-water flush removes the salt from the coil
• A pull loop of 40 mm internal diameter minimum, because a wet hand and a gloved hand both need the room

The IPX consequence of the choice is worth stating plainly because it is the thing a brand will be asked about. A three-fold roll-top holds IPX7 under IEC 60529 and it holds it under movement, which is the relevant point: a bag in a following sea is not static, and water pressure across a closure that is being worked by the motion of the boat is higher than a tank test produces. We test our marine closures on a rig that moves the bag as well as soaking it, and we report the result as IPX7 with motion rather than as a bare IPX7.

One detail that prevents the most common marine closure complaint: the pull loop has to be on the bag, not only on the slider. A slider pull alone is a small, hard object that a wet hand cannot reliably grip and that a gloved hand cannot grip at all, and it is the reason a crew leaves a zip partly closed. We add a 40 mm webbing or a cord loop at the end of the slider so the hand has something to hold, and we make the loop long enough to be found without looking, because on a dark deck at night nobody is looking.

Attachment to Lifelines, Stanchions and the Coachroof

Attachment on a boat is a specification and not an accessory, for two reasons. The first is the obvious one: an unattached bag on a heeling deck goes overboard, and it takes its contents with it. The second is less obvious and it is a safety issue in its own right: a bag sliding across a cockpit while a crew is working on it is a trip hazard and a distraction at the moment when the crew has most to do. Every marine product we build is specified with its attachment as a primary requirement.

The attachment has to suit the three common mounting positions on a boat and it has to be operable one-handed, because the other hand is holding the boat. For a lifeline or a stanchion we use two webbing loops with acetal clips, positioned so the bag is held at two points and cannot rotate. For a coachroof we use a daisy chain that clips into an existing eyestrap or a pad eye. For a bulkhead or a locker we use a strap with a cam buckle that can be tightened one-handed.

The attachment reinforcement is built to the same standard we use for a hiking pack's lash points, and for the same reason: the load is a sharp, short one. A wave breaking over the deck puts a load on the attachment that can be several times the weight of the bag, and a loop stitched to the face fabric with a short reinforcement will separate. We carry every attachment webbing at least 80 mm into the body panel and we bar-tack it into a reinforcement patch, or we weld the reinforcement on a welded build so the attachment does not introduce holes into the waterproof layer.

There is one requirement specific to a grab bag and it is worth stating because it overrides the others: a grab bag has to come free with one hand, instantly, and it must not be clipped in a way that requires the crew to look at it. We use a single loop with a 316 stainless ring and an acetal clip, we place the clip orientation so it can be found by feel, and we do not use a second attachment point on a grab bag even though two points are better for everything else. The second point costs the five seconds that matter.

Chart Tube and Navigation Storage

A chart tube is the one marine product whose primary requirement is rigidity rather than capacity, and it is the product most often got wrong. It has to be rigid when it is wet, because a soft tube will not slide into a chart berth or behind a berth cushion, and it has to be rigid while being light enough to be carried in one hand up a companionway. Those two requirements pull against each other, and the resolution is a semi-rigid construction rather than a stiff one.

We build chart tubes on a 3 mm EVA or a moulded polypropylene liner with a 600D laminate outer, closed with a three-fold roll at the top and a welded base. The rigidity comes from the liner and not from the fabric, which is the important part: a fabric-only tube that is stiff enough to hold its shape will be too heavy and will not flex enough to be stored in a berth. The roll closure at the top also lets the tube be compressed when a chart is folded rather than rolled, which is how most people actually carry a chart.

• A 3 mm EVA or moulded polypropylene liner for rigidity, with a 600D laminate outer, not a fabric-only construction
• Internal lengths of 600 mm, 750 mm and 900 mm, matching chart sizes rather than arbitrary capacities
• A three-fold roll at the top and a welded base, so the tube can be compressed for a folded chart
• An internal document sleeve in a welded, wipe-clean material, isolated from the chart volume
• A 25 mm webbing sling with an acetal clip, so the tube can be slung over a shoulder up a companionway

The document sleeve in the fourth row is what makes the product work in practice, and it is what most competitors omit. A passage plan, a list of lights and a ship's document wallet have to travel with the charts, and if they share the volume with a rolled chart they end up creased at the bottom of the tube. A welded document sleeve on the inside of the lid, in a wipe-clean material, keeps them flat and dry and it is the cheapest thing on the product. We also add a pencil sleeve, because a pencil is the one item a navigator reaches for most.

There is a UV point specific to this product that catches people out. A chart tube stored vertically in a berth is usually shaded, but one carried on deck or stored against a coachroof receives the full reflected dose, and a dark-coloured tube in the tropics will fade and then lose its coating at the fold. We build the outer in a light colour unless a client specifies otherwise, and we put the UV-stabilised coating on the outer laminate rather than relying on the liner for protection, because the outer is what the sun reaches.

Winch Tool Roll and Engine Spares Kit

A winch roll is a tool roll for a marine environment, and it differs from a ski tuner roll in two ways. The tools are greasy rather than sharp, because winch grease and spray grease are part of the job, and the roll lives in a lazarette or an engine bay where it is damp, salty and hot. The requirement is therefore wipe-clean on the inside, puncture resistant at the sleeve ends, and stable in a damp and salty environment rather than in a cold one.

We build the outer from a PVC-coated scrim or from a 1000D TPU-laminated nylon, both chosen for abrasion rather than for weight, and we line the roll with a welded, wipe-clean liner. The sleeves are individual and graded, each with a retaining flap, and each with a double layer at the closed end so a spanner or a winch handle cannot work through. The roll closes around the tools and is carried with a webbing strap and an acetal cam buckle, never a zip, because a zip with grease and salt in the coil is a zip that stops working.

• PVC-coated scrim or 1000D TPU-laminated nylon outer, chosen for abrasion in a lazarette
• A welded, wipe-clean liner, isolated at one end of the roll so the grease does not reach the tools
• Individual sleeves at 30 mm, 50 mm and 80 mm with retaining flaps and a double layer at the closed end
• A webbing strap with an acetal cam buckle as the closure, never a coil zip in this environment
• A rolled diameter under 160 mm, so the roll fits a lazarette shelf or an engine bay locker

An engine spares kit is the companion product and it is specified by a different principle: it must be identifiable in the dark, in a hot engine bay, by someone whose hands are oily. We build it with a hi-vis inner lining, a clear-view top panel where a brief allows one, and labelled zones for impellers, belts, filters and hose clips. Every item in a spares kit is one that will be needed at sea, and every one is ruined by salt water, so the bag itself is built to 20,000 mm with a welded body despite living inside the boat.

The reason for the high water column on an internal product surprises buyers, and the answer is that a lazarette and an engine bay are the wettest places on a boat. Bilge water, a leaking shaft seal and a condenser drip all end up there, and a spares kit that has taken water is a spares kit whose impellers and belts are contaminated with salt. We build an internal spares bag to the same 20,000 mm shell and the same welded construction as a deck bag, and we put a drain and four moulded feet on the base so it can sit in a damp locker and dry underneath.

Liferaft, Grab Bag and Safety Storage

A grab bag is the one marine product where the consequence of a poor design decision is not a return but an incident, and we specify it accordingly. The requirements are narrow and they are all about the first two minutes: the bag must float, it must be visible, it must come free with one hand, and the four things that matter most must be at the top. Everything else is secondary, including capacity.

The buoyancy requirement is met in two parts, and the two together are what makes the bag dependable. The first is a sealed, welded body that displaces water, which we measure by the same displacement method we use for a kayak bag and report in litres for a stated load. The second is a bonded closed-cell foam panel in the lid or the base, which provides between 3 and 6 litres of permanent displacement and means the bag floats even if it is open. We do not ship a grab bag without the second, because a bag whose flotation depends on its closure is not flotation at all.

The layout is specified as a vertical order and it is tested by retrieval rather than by inspection. The order we build to is a handheld VHF and an EPIRB at the very top, then flares and a first aid kit, then water and food, then a torch and spare batteries, and documents and a knife in an external quick-access pocket. Each zone is a different colour and each is labelled on both sides, because a grab bag is used in the dark, in a moving boat, by someone who has not opened it before.

The external quick-access pocket for a knife is a specific requirement and it is the one most often designed badly. A knife in a grab bag is for cutting a liferaft painter or a wrapped line, and it has to be reachable with one hand without opening the bag. We put it in an external sleeve on the shoulder strap side, held by an acetal clip and a webbing tab, with the handle presented upward so the hand grips it correctly in the dark. A knife buried anywhere else in the bag is a knife that is not there when it is needed.

Failure Modes Seen on Returned Marine Bags

Marine returns cluster on hardware and on coating, in that order, and every one of them is a specification decision. The list below is in rough order of frequency and it is the list we put in front of a client before sampling, because each of these is cheaper to design out than to warranty.

1. A plated buckle or slider that has seized or fractured. Plated metal has no place on a boat. Fix: acetal for every buckle, clip, slider and cord lock, and 316 stainless only where a brief demands it.
2. A zip that will not run after a season. Salt has crystallised in the coil. Fix: a 6 mm rinse channel at the base of the run, plus a 40 mm pull loop so it can be worked wet.
3. A coating that has cracked at a fold while the fabric still looks sound. UV attacked the coating first. Fix: a TPU laminate with a UV-stabilised coating, verified across 500 hours of combined exposure.
4. A bag that has gone overboard because it was not attached. Attachment was treated as an accessory. Fix: two attachment points built to 250 N as a primary specification, operable one-handed.
5. A seam that has wept. The seam was taped and the adhesive failed in heat cycling. Fix: weld the external seams on a TPU build and reserve taping for internal junctions.
6. A bag that smells and has mildew. It was stored closed and damp in a locker. Fix: a drain at the lowest point of every pocket, four moulded feet, and a printed care card telling the owner to dry it open.

The third item on that list is the one a buyer cannot evaluate from a sample, and it is the reason we publish the 500-hour result. A new marine bag looks identical regardless of whether its coating will survive a season, and the difference only appears at the end of it. We would rather lose a quotation on price to a supplier who has not run the sequence than lose the client in the second summer, and we say that in the quotation itself rather than afterwards.

The sixth item is a use-phase failure rather than a build defect, and it is worth including because it generates more complaints than most genuine faults. A bag stored closed and damp in a locker will develop mildew regardless of its fabric, and the two measures that prevent it are structural: a drain at the lowest point of every external pocket, so water does not sit, and four moulded feet, so air moves under the base. We build both into every marine product and we print the care instruction on the card that ships with it.

MOQ, Sampling and Marine Bag Lead Times

The commercial terms for a marine programme are the ones we publish for every category. Minimum order is 500 pcs per style per colour. Sampling is 6-10 working days for a deck bag, a chart tube or a winch roll, and 12-15 working days where the brief calls for a moulded liner, a custom attachment set or a foam-filled grab bag. Bulk production is 35-50 days from sample approval, inspection is to AQL 2.5 under ISO 2859-1, and the trade terms are FOB Xiamen with T/T 30 percent deposit and 70 percent before shipment.

1. Brief received with the family, the mounting position on the boat and the capacity
2. Material and hardware proposal, with the shell, the attachment rating and the closure stated as numbers
3. Prototype built on production tooling in 6-10 working days, or 12-15 with a moulded or a foam-filled component
4. The 500-hour combined salt spray and UV sequence started on the finished sample, with flexing at every cycle
5. Closure tested on a moving rig for IPX7 with motion, and attachment pull-tested to its rating
6. Approval, deposit, and bulk production in 35-50 days with a final AQL 2.5 inspection before FOB Xiamen shipment

QUANZHOU JUNYUAN BAGS has produced sewn and welded bag programmes since 2014, and our founder has worked in the category since 2004. Our validated production partner facility is SGS-verified at 4,950 square metres with 7 production lines, 149 machines, 137 staff and a monthly capacity of 200,000 pieces. QC runs to ISO 9001-aligned procedures and a BSCI audit can be hosted, with product compliance covering CE, CPC, RoHS and REACH and material testing supported by SGS. For marine programmes we add the 500-hour exposure record, the displacement figure and the attachment pull test to that file. Contact service@junyuanbags.com or WhatsApp +86 177 5002 0688, or begin with our custom development page. Our waterproof standards page sets out how each named test method is applied.

One closing note for a brand planning a marine range, because it determines the order in which to develop. Lead with the deck bag and the winch roll, because they are the two products a boat owner will actually buy and they are the two that carry a brand into a chandler. Develop the grab bag second, because it is the product that establishes whether you are taken seriously in the market, and do it properly or not at all. A grab bag that does not float, does not stay visible and cannot be released with one hand should not carry a brand name into the marine market.

Frequently Asked Questions

Q1: What makes a sailing bag different from a waterproof hiking pack?

A: Three things attack it at once: salt crystal abrading at every fold, a UV dose roughly double the land figure because the boat reflects, and constant wetting. That combination rules out a PVC-coated scrim on deck, rules out plated metal hardware entirely, and means we weld the external seams rather than tape them, because an adhesive bond will not survive heat cycling in a marine environment.

Q2: Why do you exclude plated metal hardware on marine bags?

A: Because it corrodes in a salt atmosphere and the failure is functional rather than cosmetic. A corroded buckle seizes and then fractures under load, a corroded slider stops tracking and jams, and a cord lock's spring corrodes first, which means a bag that will not open. We use acetal throughout and 316 stainless only where a brief demands it.

Q3: What is the 500-hour salt spray and UV sequence?

A: An alternating cycle of 4 hours of salt spray exposure to the method in ISO 9227, 4 hours of accelerated UV, and 1 hour of drying at 40 degrees C, repeated to 500 exposure hours on a finished sample with its hardware fitted. Every fold is flexed and every closure cycled at the end of each cycle, and the hydrostatic head is re-measured to ISO 811 at 250 and 500 hours.

Q4: Which shell fabric works on a boat deck?

A: A 600D or 840D TPU-laminated polyester or nylon at 20,000 mm+ with a UV-stabilised coating. A PVC-coated scrim matches it for abrasion and price but loses its coating integrity in a season of direct sun over water, so we reserve it for lazarette and locker storage where UV is not a factor.

Q5: Do you weld or tape marine bag seams?

A: We weld the external seams wherever the geometry allows, because a taped seam depends on an adhesive that UV, salt and heat cycling will attack, and an RF weld on a TPU laminate is stronger than the fabric either side of it. We reserve a taped seam for internal junctions on a complex shape and we state which is used on the spec sheet.

Q6: How should a marine bag attach to a boat?

A: With two attachment points built to 250 N, operable one-handed, because the other hand is holding the boat. For a lifeline or stanchion we use two webbing loops with acetal clips, for a coachroof a daisy chain into a pad eye, and for a locker a strap with a cam buckle. Attachment is a primary specification in this category, not an accessory.

Q7: Why does a marine zip need a rinse channel?

A: Because a crew member flushing the bag with fresh water will clean the face fabric and leave the salt in the coil, since the coil is shielded. A 6 mm channel at the base of the zip run lets flush water pass through the coil and carry the salt out, and it roughly doubles the service life of the zip.

Q8: What IP rating should a sailing deck bag have?

A: IPX7 under IEC 60529, and we test it on a moving rig rather than a static tank, because a bag in a following sea is not static and water pressure across a closure being worked by the motion of the boat is higher than a tank produces. We report the result as IPX7 with motion, not as a bare IPX7.

Q9: How is a grab bag different from a normal deck bag?

A: It is a safety product and every requirement serves the first two minutes. It must float on a bonded foam panel as well as on its sealed body, it must be hi-vis, it must release with one hand in under 3 seconds, and the four most critical items must be at the top. It uses one attachment point rather than two, because the second costs the five seconds that matter.

Q10: Why is a chart tube built with a liner?

A: Because a tube rigid enough to slide into a chart berth cannot be made from fabric alone without becoming too heavy and too stiff to store. A 3 mm EVA or moulded polypropylene liner provides the rigidity and a 600D laminate provides the outer, and a three-fold roll at the top lets the tube compress for a folded chart.

Q11: What is the minimum order quantity for marine bags?

A: The minimum is 500 pcs per style per colour, so a two-colour launch is a 1,000-piece commitment. Most marine brands launch one shell colour with the accent on the binding, the webbing and the attachment loops, which keeps the commitment at 500 pieces and leaves the budget for the hardware specification.

Q12: How long does marine bag sampling take?

A: Sampling is 6-10 working days for a deck bag, chart tube or winch roll, and 12-15 where the brief needs a moulded liner, a custom attachment set or a foam-filled grab bag. Because the 500-hour exposure sequence is a long test, we start it as soon as the prototype is built and the sample is reviewed against it.

Q13: What is the bulk production lead time for marine bags?

A: Bulk production takes 35-50 days from sample approval, depending on fabric availability and on whether moulded components are involved. Repeat orders against retained tooling typically run in a shorter 30-40 day window. Shipments move on FOB Xiamen with T/T 30 percent deposit and 70 percent before shipment.

Q14: Which inspection level applies to marine bag orders?

A: We inspect to AQL 2.5 under ISO 2859-1 as standard. For a marine bag, a critical defect includes any plated metal hardware, any attachment reinforcement under 80 mm into the panel, any missing zip rinse channel, and any seam welded where the spec sheet states taped or the reverse.

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