Tag: Anchoring

  • Floating Dock on a River: Current, Debris and Changing Water

    Floating Dock on a River: Current, Debris and Changing Water

    A river house in June is hard to beat: the boat tied up out front, kids fishing off the end, the water sliding past all day. Then the spring rains come upstream, the river rises a few feet overnight, and a log the size of a canoe drifts down and lodges against the dock. A floating dock on a river lives with three things a lake dock rarely sees: constant current, floating debris and big changes in water level. This guide explains what each one means for the dock you choose, how it is held in place, the rules that apply on rivers, and when an inflatable dock is the wrong tool.

    Man clearing a floating branch from an inflatable dock on a river

    In short: on a river, use a rigid floating dock held by hardware that lets it rise and fall but not drift (pipes in collars, piling brackets or stiff arms), with a hinged gangway for level changes. Consumer inflatable docks are a poor fit for current: RAVE tells owners not to use its dock in currents, and Aquaglide says sites with strong currents should consider up to 50% more anchor weight. States such as Iowa and Illinois require river docks to be securely anchored so they do not become floating hazards in high water. Check federal, state and local rules before you install.

    Why a floating dock on a river is different

    • Current never stops. On a lake, wind loads a dock now and then. On a river, the water pushes on it all the time, and harder when the river is high.
    • Debris arrives with the current. Branches, logs and trash catch on the upstream edge, add load and can puncture or scrape.
    • The level moves. Rivers can rise and fall several feet with rain upstream or dam releases, so lines and gangways that fit in the morning can be too short or too long by evening.
    • Ice moves too. Where rivers freeze, ice shifting in the thaw is what damages docks; Candock says most ice damage happens then.

    Inflatable docks and river current

    We like inflatable docks on lakes and at anchor, but we are cautious about them on moving water, and the makers are too. RAVE’s owner’s manual for its Aqua Dock tells users never to use it in high winds, waves or currents, and not to connect it directly to docks, piers or other hard objects. Aquaglide, writing about its anchored lakefront products, says sites with strong tides, currents, winds or swell should consider up to 50% more weight or holding power. None of the consumer dock makers we checked publishes a current, wind or wave limit, so there is no number to work to.

    If you use an inflatable on a river at all, keep it to slack water: a backwater, a still side channel or a cove where the current is barely moving, on a calm day, attended, and out of the water when the river is up. For a dock that lives on the river all season, look at rigid docks.

    Holding a river dock in place

    River docks are usually held by hardware that controls sideways movement while letting the dock float up and down. EZ Dock lists pipes, deadweight anchors, piling brackets and stiff arms as its anchoring options, with hardware for fresh and salt water.

    MethodHow it worksRiver notes
    Pipes in collarsPipes set in the bottom pass through collars on the dock (Connect-A-Dock kits have pole anchoring connectors for Schedule 40 pipe)Pipe length must cover the high-water mark; best in shallower water
    Piling bracketsBrackets slide on fixed pilingsPilings are a construction job and often need a permit
    Stiff armsRigid arms hinge between shore and dockHold the dock off the bank as the level changes
    Deadweights and linesHeavy weights on the bottom with lines or chainLines must be long enough for high water without letting the dock swing into the bank or channel

    Rigid modular docks are designed with wave loads in mind: EZ Dock says its couplers are designed to break before the dock section in strong wave action, so the repair is a coupler, not a section. Ask the dealer to size the anchoring for your river, depth and current, and get it in writing.

    Planning for rising and falling water

    • Know your range. Find the nearest US Geological Survey streamgage and look at its history. USGS WaterAlert sends email or text notifications when water conditions cross thresholds you choose, which is a simple way to know when to check the dock.
    • Hinge the gangway. A gangway hinged at both ends follows the dock up and down; EZ Dock offers wood, polyethylene (up to 18 ft) and aluminum gangways.
    • Check low water too. Make sure the dock still floats at the lowest level you expect and does not settle onto rocks.
    • Have a high-water plan. Know in advance whether you will pull the dock, swing it in to the bank or leave it; Iowa makes riparian owners responsible for retrieving a dock that becomes a navigation hazard.

    Debris and inspections

    After every rise, walk the dock: clear branches from the upstream side, look at lines, chain and shackles for chafe, and check couplers, cleats and nuts. Candock, for example, asks owners to check the nuts on cleats, ladders and connecting pins occasionally. Keep a repair kit for anything soft on the dock, such as an inflatable swim pad or fenders. Never go out on a dock in flood: the National Weather Service warns that 6 in of fast-moving flood water can knock over an adult.

    Long line for high water

    Better Boat 3/8 in Nylon Anchor Line, 100 ft

    • 820 lb working load
    • 4,035 lb breaking load
    • Stainless thimble
    Check price on Amazon
    Shock cord and chain

    RAVE Sports Anchor Connector Kit

    • 6 ft shock cord
    • 15 ft nylon rope
    • Galvanized chain, float
    Check price on Amazon
    Patch kit

    JLF Inflatable Repair Kit with HH-66 Cement

    • Five PVC patches
    • 1 oz vinyl cement
    • Valve wrench
    Check price on Amazon

    River dock permits and rules

    Rivers are more likely than ponds to be navigable waters. In US navigable waters, the Army Corps of Engineers treats piers and boat docks as structures that need a Department of the Army permit unless they are exempt or covered by a general permit. States add their own rules, and some are written with rivers in mind:

    • Iowa: “All river docks must be securely anchored to prevent them from becoming floating hazards during times of high river flows,” and the riparian owner is responsible for retrieving and removing a dock when needed to prevent or remove a navigation hazard.
    • Illinois: its statewide permit for minor private docks requires a dock to be securely anchored against high water or winds, to project no more than 50 ft and never more than a quarter of the waterway’s width, to stay within navigation limits, and to be no more than 10 ft wide.

    These are examples, not your rules. Check with your state natural resources agency, county, any river authority or water management district, and the Corps district office before you buy.

    Choosing a dock for a river

    • Tell the dealer it is for a river, with the depth range and how fast the current runs at your bank.
    • Prefer rigid modular sections with river-rated anchoring over a single inflatable deck.
    • Keep it short and close to the bank; the rules above limit how far you may reach into the channel.
    • Plan to remove it before ice moves, as Connect-A-Dock recommends where ice shifts.
    Custom built: request information

    FunAir Toy Island

    by FunAir

    • Stated capacity: Up to 4 jet skis or dinghies, or 2 Seabobs plus guests (maker)

    Full specs and sources

    Request more information

    Jobe Infinity Dock

    by Jobe

    • Size (as stated): 250 x 233 cm
    • Stated capacity: 300 kg maximum user weight
    • Thickness: 20 cm

    Full specs and sources

    See it at Nootica

    Jobe Infinity PWC Dock

    by Jobe

    • Size (as stated): 345 x 250 cm
    • Thickness: 20 cm

    Full specs and sources

    See it at Nootica
    Custom built: request information

    NautiBuoy Jet-Ski Dock

    by NautiBuoy Marine

    Full specs and sources

    Request more information

    Northern Diver FloatDeck

    by Northern Diver

    • Size (as stated): 1 to 10 m lengths
    • Thickness: 8 cm drop-stitch

    Full specs and sources

    See it at Northern Diver

    Related: how to anchor a floating dock, floating dock installation, floating dock kits vs inflatable docks, the modular docks hub and the Setup and Care guide.

    River dock questions

    Can I put an inflatable dock on a river?

    Only in slack water, and check your manual first. RAVE says not to use its inflatable dock in currents, and no consumer maker we checked publishes a current limit.

    How do floating docks handle river level changes?

    They float up and down, so the anchoring has to slide or flex with them: pipes through collars, brackets on pilings, stiff arms, or lines with enough length. A hinged gangway connects the moving dock to the fixed bank.

    Should I take my river dock out before a flood?

    If you can do it safely before the water rises, it is often the simplest way to protect the dock and keep it from becoming a hazard downstream. Once the water is up and fast, stay off it.

    Do I need a permit for a floating dock on a river?

    Often. Many rivers are navigable waters under federal rules, and states such as Iowa and Illinois set conditions for river docks. Check before you install.

  • How to Anchor a Floating Dock: Anchors, Weights, Lines, Bridles

    How to Anchor a Floating Dock: Anchors, Weights, Lines, Bridles

    The first afternoon breeze on a lake is the test. A dock that was sitting nicely off the beach at breakfast starts to swing, drags a little, and by three o’clock it is nosing into the neighbor’s lift. Many floating dock problems come back to the same thing: anchoring a floating dock properly, with enough weight, the right lines and the right spot. This guide covers how to anchor a floating dock, inflatable or rigid, using the figures makers actually publish, and it tells you where they publish nothing.

    In short: follow your maker’s numbers first. Aquaglide asks for at least 1,100 lb of total anchor weight on its Docking Station and 4,400 lb on its C Lounge; RAVE suggests about 150 to 200 lb for its 10 x 10 ft Aqua Dock, depending on the lake and bottom. Use anchors suited to your bottom, lines with enough scope (boating guides use 5:1 to 7:1 for boats), a bridle where the dock has several anchor rings, and keep the dock away from piers, boats and other hard objects. Rigid docks are pinned with pipes, deadweights, piling brackets or stiff arms.

    Start with what your dock maker says

    Makers publish very different anchoring figures, because their docks are very different. These are the ones we found, as the makers state them:

    DockAnchor pointsAnchor weightDepth and distance
    Aquaglide Docking Station (14 ft 9 in x 10 ft 5 in)5 anchor ringsAt least 1,100 lb (500 kg) totalAt least 4 ft deep, 10 ft from shore
    Aquaglide C Lounge (14.7 ft)4 anchor ringsAt least 4,400 lb (2,000 kg) totalAt least 4.8 ft deep, 3.3 ft from shore
    RAVE Aqua Dock 10 (10 x 10 ft)2, one at each end on the bottomAbout 150 to 200 lb, depends on lake and bottom (RAVE FAQ)At least 4 ft deep
    Rigid sections (EZ Dock, Connect-A-Dock)Pipe collars, pole connectors, bracketsSet by dealer for the siteSite specific

    Two things stand out. First, Aquaglide’s figures are far higher than most owners expect, and Aquaglide says its weight recommendations are for anchoring in extreme weather, waves or other abnormal conditions, and advises a dock and mooring specialist for the install. Second, no consumer dock maker we checked publishes a wind or wave limit. That is why the maker’s anchor weight is the number to respect, and why you should bring the dock in, or stay off it, when weather turns.

    Floating dock anchors: the main types

    • Deadweight anchors. Anything heavy that sits on the bottom: concrete blocks, filled anchor bags or purpose-made weights. Aquaglide’s Lakefront Anchor Bag holds about 110 lb (50 kg) when filled with sand, and several bags can share one line to reach a large total.
    • Mushroom anchors. Cast bowls that settle into soft bottoms. A 10 lb SeaSense mushroom is sold for sandy, muddy or weedy bottoms and small boats; on its own it is far below the totals above, so it suits small, light setups or as one of several anchors.
    • Pipes and poles. For rigid kits in shallow water: Connect-A-Dock’s kit has pole anchoring connectors for Schedule 40 pipe (not included), and the dock slides up and down the pipe as the water changes.
    • Stiff arms and piling brackets. Rigid arms from the shore or brackets on pilings that hold the dock in place while letting it rise and fall. EZ Dock lists pipes, deadweight anchors, piling brackets and stiff arms as its options, with fresh and saltwater hardware.

    Match the anchor to the bottom. The BoatUS Foundation notes that lightweight fluke anchors hold best in hard sand or mud, not in very soft mud or grass, and that plow anchors work in sand, rock, weeds and grass but poorly in soft bottoms. For a dock that stays put for weeks, deadweight is the usual answer, because it does not depend on digging in.

    Lines, scope and chain

    Scope is the length of line compared with the depth of water. For anchoring boats, the BoatUS Foundation teaches 7:1, or 5:1 for a small boat with a light anchor in good weather, and a state boating course adds 7 to 8 ft of galvanized chain at the anchor end to lower the angle of pull. Docks are moored rather than anchored like boats, and makers set their own line arrangements, but the idea holds: a short, steep line lifts the anchor; a longer line with some chain keeps it on the bottom. Allow for the dock swinging in a circle and keep that circle clear of swimmers’ routes, boats and other docks.

    Use marine line rated well above the load. Better Boat’s 3/8 in double-braided nylon, for example, lists an 820 lb working load and a 4,035 lb breaking load. The working load is the figure to plan with. A shock cord near the dock absorbs movement and stress; RAVE sells an anchor connector kit with a 6 ft shock cord, 15 ft of nylon rope, galvanized chain and a foam float.

    Small extra anchor

    SeaSense Mushroom Anchor 10 lb

    • Vinyl-coated cast iron
    • Sandy, muddy, weedy bottoms
    • About $32
    Check price on Amazon
    Anchor line

    Better Boat 3/8 in Nylon Anchor Line, 100 ft

    • 820 lb working load
    • 4,035 lb breaking load
    • Stainless thimble
    Check price on Amazon
    Shock-absorbing connector

    RAVE Sports Anchor Connector Kit

    • 6 ft shock cord
    • 15 ft nylon rope, chain
    • Foam marker float
    Check price on Amazon

    What a bridle does

    A bridle is a set of short lines that run from several anchor rings on the dock to one point, often a swivel, where the main anchor line attaches. It spreads the pull across the dock instead of yanking one corner, and the swivel lets the dock turn with the wind without twisting the line. In one of its lakefront manuals, Aquaglide describes a single vertical mooring line to the center swivel of a 4-way bridle with an appropriate weight, and tells owners to secure the swivel and connections so they cannot loosen in rough weather. Aquaglide’s Docking Station has five anchor rings and ships without a bridle, so buy or make one rated for the job.

    How to anchor a floating dock, step by step

    1. Read the manual. Note the anchor weight, anchor points, minimum depth and distance from shore.
    2. Pick the spot. Check depth with a weighted line at the lowest water you expect, and leave room for the dock to swing clear of piers, lifts, boats and swim lanes.
    3. Place anchors first. Aquaglide’s instructions say to install anchors and mooring lines before inflating its product. Lower weights from a boat; never throw them.
    4. Attach the bridle or lines to every anchor point the maker provides, using shackles or locking carabiners.
    5. Set the length so the dock floats flat at today’s level with some slack for waves and level changes.
    6. Check after an hour and after the first wind. If it has moved, add weight. For sites with strong wind, current or swell, Aquaglide suggests up to 50% more weight or holding power.

    Keep it away from hard objects

    It is tempting to tie an inflatable dock to the end of a pier. RAVE’s manual says not to connect its Aqua Dock directly to docks, piers or other hard objects, and Aquaglide says never to tie its lakefront product to a dock. Anchor it on its own instead. If you tie a dock off a boat for the afternoon, do it at anchor with the engine off, and remember the CDC’s advice to stay at least 20 ft from boats running an engine or generator because of carbon monoxide.

    Local rules

    Anchoring is also a legal matter in many places. Illinois’s statewide dock permit requires docks to be securely anchored so they do not break loose and become a floating hazard in high water or wind. Minnesota’s boating guide says swimming rafts and similar structures not attached to shore may not stay in the water between sunset and sunrise without a county sheriff’s permit, with a light or reflectors. Check your state and lake rules before you leave a dock out overnight.

    Next steps: floating dock installation, a floating dock on a river (current changes everything), portable docks, floating docks for ponds and lakes, the Setup and Care guide, and the lake docks hub. Words like scope, bridle and freeboard are in the glossary.

    Anchoring questions

    How much weight do I need to anchor a floating dock?

    Whatever your maker states. The figures we found range from about 150 to 200 lb (RAVE, 10 x 10 ft inflatable) to 1,100 lb (Aquaglide Docking Station) and 4,400 lb (Aquaglide C Lounge). We do not calculate anchor weight from size; if your maker publishes nothing, ask them, or a local dock and mooring installer.

    One anchor or two?

    Use every anchor point the maker provides. RAVE’s dock has two, one at each end; Aquaglide’s Docking Station has five. Two or more anchors stop the dock spinning and spread the load.

    Can I use cinder blocks as floating dock anchors?

    People do, but no dock maker we checked specifies them. Makers sell purpose-made weights instead; Aquaglide says its sand-filled anchor bag is unlikely to damage boats or inflatables. Whatever you use, reach the maker’s total weight.

    How deep should the water be?

    RAVE and Aquaglide ask for at least 4 ft under the docks above, and 4.8 ft for the C Lounge. If people will jump, look for more.

    How do I anchor a dock where the water level changes?

    Leave slack, check often, or use hardware that slides: pipes through collars, piling brackets or stiff arms on rigid docks. For big swings, see our river guide.