Foil-to-Board Hardware • M8 • T40 • DropBox
North DropBox Screw Pack
Complete replacement foil-to-board mounting hardware for compatible North DropBox installations.
The North DropBox Screw Pack gives you four matching M8 countersunk T40 screws and four T-nuts for securing a compatible Sonar Board Adaptor or Carbon Foil Mast to a foilboard track system. Choose 23mm, 25mm or 30mm to match the exact bolt length specified for your board and mast connection—because correct thread engagement matters just as much as track spacing.
- 23mm / 25mm / 30mm options
- Four M8 T40 screws
- Four T-nuts
- Foil-to-board mounting
Best for: replacing worn or missing North DropBox mounting hardware, building a spare travel kit, or completing a foil setup that does not already include the correct mast-to-board screws and track nuts.
Why Keep a DropBox Screw Pack in Your Foil Kit?
A complete four-point set
Each selected size includes four matching screws and four T-nuts, giving you the full hardware set required for a compatible four-bolt mast or board-adaptor connection.
Secure countersunk fit
The M8 countersunk heads are shaped to seat correctly in compatible North mounting plates, while the T40 drive supports positive tool engagement during careful hand installation.
Fast DropBox setup
On a compatible DropBox system, the screws and T-nuts can remain attached to the foil, drop into the track openings and slide into position before final tightening.
Useful backup hardware
A correctly sized spare set can save a session when a screw or T-nut is lost, damaged or showing corrosion—but only when it matches the hardware specified for your setup.
Choose the Correct Screw Length
| Size | Pack Contents | Recommended Selection Guide | North Product Code |
|---|---|---|---|
| 23mm |
4 × M8 × 23mm countersunk T40 screws 4 × T-nuts |
Choose only when your original hardware or the board and foil instructions specifically require 23mm screws. This is not a universal track size. | 85009.230135 |
| 25mm |
4 × M8 × 25mm countersunk T40 screws 4 × T-nuts |
Designed for attaching a Sonar Board Adaptor or Carbon Foil Mast to the North Scoop Mini DropBox Foil Mounting System. | 85009.220134 |
| 30mm |
4 × M8 × 30mm countersunk T40 screws 4 × T-nuts |
Standard North DropBox foil-to-board hardware used with compatible Sonar Board Adaptors or Carbon Foil Masts. Supplied with various North Scoop, Swell and Seek foilboards. Confirm your exact board model and year. | 85009.200133 |
Do not choose by track spacing alone. A board may use 90mm foil tracks and still require a different screw length. Screws that are too short may not provide enough thread engagement; screws that are too long can bottom out before the mast plate is securely clamped.
Foil and Board Compatibility
The 25mm and 30mm packs are purpose-built foil-to-board hardware for compatible North DropBox connections using a Sonar Board Adaptor or a direct-mount Carbon Foil Mast, including the mast found in the North Sonar Carbon Foil Edition. The correct length depends on the board construction, track depth and mounting plate—not simply the brand of foil or the 90mm distance between tracks.
For any non-North foilboard, including an F-One board, first confirm that the M8 T-nuts fit the tracks, the countersunk heads seat correctly in the North mast plate, the screws provide at least 8mm of thread engagement and the screw tips do not bottom out in the tracks. Follow the board manufacturer’s hardware guidance; if any measurement is uncertain, contact Windance before ordering or assembling the foil.
Important: this is the mast-to-board screw pack. It does not replace the separate front-wing, fuselage or stabilizer screws used elsewhere in a North Sonar foil assembly.
What’s Included
Included with your selected size
- Four M8 countersunk T40 screws in the selected 23mm, 25mm or 30mm length
- Four compatible T-nuts
Not included
- T40 tool or torque wrench
- Marine grease
- Foil mast, board adaptor or foilboard
- Front-wing, fuselage or stabilizer hardware
Installation and Care
- Confirm the required screw length before assembly; compare with the board manual or the correctly specified original hardware.
- Clean sand, salt and dirt from the screws, T-nuts, mast plate and board tracks.
- Apply a light coating of marine grease to the screw threads to help reduce corrosion and seizing.
- Start all four screws by hand, align the mast and tighten gradually in a diagonal pattern using a T40 tool.
- Do not use power tools and do not overtighten. Follow the board and foil manufacturers’ current assembly and torque instructions.
- Rinse with fresh water after saltwater use and inspect the hardware regularly for damaged threads, corrosion or a worn drive head.
North DropBox Screw Pack FAQ
Which North DropBox screw length should I choose?
Match the length specified by your board and foil instructions or the known-correct original hardware. Use 25mm for the Scoop Mini DropBox application, and use 30mm for compatible standard North DropBox applications. Select 23mm only when your equipment specifically calls for 23mm screws. Do not select a length from track spacing alone.
Does every size include T-nuts?
Yes. Each 23mm, 25mm or 30mm pack includes four M8 countersunk T40 screws in the selected length and four T-nuts.
Will the 30mm pack fit every board with 90mm foil tracks?
No. The 90mm track standard describes track spacing, not the required bolt length. Track depth, mast-plate thickness, countersunk-head seating and thread engagement must all be checked before installation.
Can I use this screw pack with an F-One Rocket FREE board?
It may be compatible with a particular board and North mast combination, but the size cannot be guaranteed from the 90mm track spacing alone. Confirm M8 T-nut fit, correct countersunk-head seating, at least 8mm of thread engagement and sufficient clearance so the screws do not bottom out. Contact Windance with the exact board model, model year and foil mast if you need help confirming the hardware.
Does the North Sonar Carbon Foil Edition already include foil-to-board screws?
No. The Sonar Carbon Foil Edition includes the mast, fuselage, stabilizer, covers, travel bag, tool kit and the hardware used to connect its foil components, but the DropBox mast-to-board screw pack is separate.
Is a T40 tool included?
No. The pack contains four screws and four T-nuts. A compatible T40 hand tool is required for installation.
Is this the correct hardware for a front wing or stabilizer?
No. This pack is specifically for connecting a compatible foil mast or Sonar Board Adaptor to the foilboard. North front wings, fuselages and stabilizers use separate size-specific hardware.
Should I grease the screws?
Yes. A light coating of suitable marine grease on clean threads helps reduce corrosion and seizing. Rinse the assembly after saltwater use, inspect it regularly and replace hardware with damaged threads or a worn T40 head.
Need Help Choosing 23mm, 25mm or 30mm?
The safest choice is the exact length specified for your board-and-mast combination. If you are replacing lost hardware or mounting a North foil to a non-North board, call Windance at 1-800-574-4020 with the board model, model year and foil mast before ordering.