Installing a bait board is one of those jobs that looks straightforward on paper and gets complicated quickly the first time you actually do it. Pick the wrong position and you’ll be uncomfortable using it for years. Use the wrong fixing and the board flexes or detaches in chop. Use the wrong sealant and you create a slow water ingress point that quietly rots the deck core.
This guide walks through a complete bait board installation from tool selection through final fit-up. The instructions assume a fibreglass boat with a typical fibreglass or composite gunnel and a standard SeaKing flat-mount board. Leg-mount boards (the SKL series) follow similar principles but with the legs clamping or bolting to a leaning post or deck-mounted post bracket.
What you’ll need
Tools:
- Drill with a quality cobalt or HSS twist drill bit set
- Measuring tape and pencil/marker
- Spirit level (small bullseye level if available)
- Sharp knife or scribe
- Caulking gun
- Screwdriver or socket set matched to your hardware
- Cordless impact driver (helpful but not essential)
- Vacuum cleaner
- Masking tape
- Light source (LED head torch is useful)
Materials:
- 316 marine-grade stainless steel bolts, washers, and nylock nuts (size depends on board — typically M6 or M8)
- Stainless backing plates or large-diameter penny washers (critical — never bolt without backing)
- Marine-grade polyurethane sealant (Sikaflex 291 or 3M 4000UV are the standard choices)
- Optional: anti-seize compound for bolt threads
- Cleaning cloths and isopropyl alcohol or acetone for surface prep
Step 1: Choose the mounting position
The single most important decision in the whole installation. Take your time. A bait board mounted in the wrong position is a problem you live with for years.
Sit at the helm, then move to the position where you’d actually fish. Most anglers don’t fish from the helm — they fish from the rear cockpit or sides. Mount the board where you’ll use it, not where it looks tidiest from outside the boat.
Check your access. Can you reach the board comfortably from your fishing position without leaning awkwardly? Can you reach the sink to drain it? Can you access all rod holders (if integrated) without the board obstructing them?
Check it doesn’t interfere with other gear. Will the open transom door clear the board? Does it block access to a hatch, a livewell, the bilge, or a battery box? Does it sit clear of where you’d land a fish over the gunnel? Does it interfere with the bimini frame when erected?
Check the structural attachment point. The mounting surface needs to be solid. On most modern fibreglass boats, the gunnel rail is laminated structurally and capable of taking bolts. But some cheaper boats have hollow gunnel sections that aren’t designed for fastening. Tap the underside of the proposed mounting area — a solid sound is good; a drum-like hollow sound means the structure is thinner than ideal and may need a backing plate or alternative position.
Sit a foam offcut, cardboard template, or the board itself in position and walk around the boat. Climb in and out. Move to your usual fishing positions. If anything feels wrong, move it. Do this for at least 10 minutes before drilling — once the holes are in, you’re committed.
Step 2: Mark and measure carefully
Once you’ve settled on the position, mark the bolt hole locations using the board itself as a template — or, if the board has dust covers protecting the hardware area, use the supplied template (most SeaKing boards include one in the box).
Place the board exactly where you want it mounted. Have a second person hold it level if possible. Mark each bolt hole position with a pencil through the mounting holes onto the gunnel surface.
Cross-check measurements. Measure from a fixed reference point (the front edge of the gunnel, the joint between gunnel and hull) to each hole location. Front-left and front-right hole positions should be the same distance from the bow reference. The board should be square to the boat’s centreline, not tilted. Use a tape measure both ways and confirm before drilling.
Mark the drill point with a centre punch or scribe. This stops the drill bit from wandering when you start the hole.
Step 3: Drill the bolt holes
This is where most installation errors happen. Drill carefully.
Use the right bit size. The bit should be slightly larger than the bolt diameter — typically the bolt diameter plus 1 mm for stainless bolts in fibreglass. So an M6 bolt uses a 7 mm bit, an M8 bolt uses a 9 mm bit. Tight-fit holes cause stress cracking around the bolt over time.
Drill at low speed with steady pressure. Fibreglass cuts cleanly with a sharp bit but will burn or chip if you push too hard or run the drill too fast. Let the bit do the work.
Apply masking tape over the drill point first. This prevents the gelcoat from chipping around the hole. Tape down, drill through, peel off afterwards.
Drill from the visible side first to get a clean entry hole, then only just break through the back of the gunnel. If you fully drill through with the visible side down, the bit can chip out the gelcoat as it exits. Best practice: drill 80% from the topside, finish from underneath.
Vacuum the holes thoroughly to remove all swarf and dust. Sealant won’t bond to a dusty surface.
Step 4: Seal the holes
This is the step that’s most often skipped, and it’s the one that bites years later when water ingress quietly rots the deck core around the bolt holes.
Run a heavy bead of marine polyurethane sealant (Sikaflex 291 or equivalent) around the inside of each hole. Squeeze enough into the hole that it will be displaced when you bolt through.
Apply a generous bead around the underside of the board’s mounting flanges where they’ll contact the gunnel surface. Don’t be precious — sealant excess can be cleaned later, but missed sealant cannot be added later without removing the board.
Drop the board into position and bolt through. The sealant displaces around the bolt threads and squeezes out at the joint, sealing the contact surface and the bolt hole simultaneously.
Wipe excess sealant immediately with a cloth before it skins over. Sikaflex 291 develops a skin within 30–60 minutes; full cure takes 24 hours. Cleaned within 30 minutes, excess sealant comes off easily. Left to cure, it’s a 30-minute job per joint with isopropyl alcohol and a scraper.
Step 5: Install the bolts
Drop a stainless bolt with a stainless washer through each hole from the top. From underneath, the order is: penny washer or backing plate first, then nylock nut.
Use 316 marine-grade stainless throughout. Not 304. Not zinc-plated steel. Galvanic corrosion will eat anything other than 316 in continuous saltwater service.
Apply anti-seize compound to bolt threads if available (Loctite 8023 or Tef-Gel are common marine choices). This prevents thread galling between stainless threads, which can otherwise lock up when you eventually need to remove the bolts.
Tighten until snug, then add a quarter turn. Don’t crank the bolts down with maximum torque — over-tightening can crush the gunnel laminate or strip thread engagement. Snug-plus-a-bit is right. The nylock nut prevents loosening.
Don’t tighten one bolt fully before others are started. Fit all bolts hand-tight first, then tighten each in a cross pattern. This prevents the board from being pulled into a slightly distorted position by uneven tightening.
Step 6: Final checks
Check the board sits flat and level. Place a spirit level on the cutting surface in both directions. If it’s noticeably off-level, the gunnel surface itself is not flat (some boats have a slight slope to drain water) — fine for use, but worth knowing.
Test all rod holders, drain fittings, and accessories. Fit a rod into each holder to confirm it sits at the correct angle. Pour water into the sink and confirm it drains cleanly through the drain fitting (and out of the boat, not back into the bilge).
Wipe down all surfaces to remove any remaining sealant residue, swarf, or fingerprints.
Wait 24 hours before stress-testing. Let the sealant fully cure before subjecting the board to wave loads or rod-holder loads.
Common installation mistakes
In 20 years of marine fit-outs, the same mistakes come up repeatedly:
Skipping the sealant. “I’ll seal it later” never happens. Water gets in, runs down the bolt threads, sits in the gunnel core, and 5 years later you have core rot in a 30 cm radius around each bolt. Always seal during installation.
Wrong bolt grade. Galvanic corrosion at hardware joints is the leading cause of bait board hardware failure. Use 316 marine-grade stainless from day one.
No backing plate. A bolt through fibreglass with just a penny washer underneath will gradually pull through under load — especially with rod holders catching big fish. Use a stainless backing plate or large-diameter washer to spread the load.
Drilling oversized holes. Some installers drill 2 mm oversized to give “room for thermal expansion.” Don’t. The hole should be a clearance fit, not a loose fit. Sealant fills the small gap and the bolt sits centred.
Mounting position chosen at the helm rather than where you fish. Already covered above. Re-read.
Tightening bolts uneven. Causes the board to seat slightly distorted. Always cross-pattern tighten.
Using silicone instead of polyurethane sealant. Silicone has no place in marine fit-out. Doesn’t bond to fibreglass reliably and isn’t UV-stable. Use Sikaflex 291, 3M 4000UV, or equivalent marine polyurethane.
Special case: leg-mount installation (SKL series)
Leg-mount boards like the SKL-L06 follow different mounting principles. The legs typically either clamp around an existing structural pole (leaning post leg, T-top support, rocket launcher upright) or bolt directly to a deck-mounted base plate.
For clamp-mount installations:
- Confirm the host pole diameter matches the clamp ID
- Position the clamps where the board will be most useful, then loose-fit
- Stand the board level and confirm height suits a standing person at the deck (typical “comfortable working height” is 1100–1200 mm above deck)
- Tighten clamps progressively, checking the board remains level
For deck-bolt installations:
- Treat each leg base bolt the same as a flat-mount bolt — backing plate, sealant, 316 stainless throughout
- Multiple legs need to be installed coplanar — a slight twist between front and rear legs results in a board that rocks under load
When to call in a professional
Most bait board installations are within the capability of a competent DIYer with the right tools. Call in a marine fit-out professional when:
- Your boat’s gunnel structure looks unclear or hollow at the proposed mount point
- You’re installing on a high-value vessel where any installation error could affect resale
- You need to relocate or repair an existing failed installation (these often need core repair before remounting)
- The hardware that came with the board doesn’t match your intended mounting surface
Marine fit-out shops typically charge $200–$400 for a flat-mount bait board installation, including supply of premium sealant and 316 hardware. For complex installations with custom backing plates or core repairs, $500–$1,000.
Need help?
Bait Boards Direct supplies the boards. We don’t do installations directly, but our boards come with the standard hardware and a clear installation diagram in the box. If you have questions before or during installation — particularly about mounting position or hardware sizing for an unusual application — get in touch with photos of your boat’s gunnel area and we’ll advise.
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