How to Measure Your Boat for the Right Size Cover
Short answer: you need two measurements — the centreline length (bow to stern) and the beam (widest point of the hull) — plus your boat's hull shape (runabout, open fishing/tinny, centre console, cuddy cabin, or a T-top/bimini-equipped boat). Match those to the size chart for your hull type, then cross-check against the actual fabric length and width needed, measured over any fittings the cover has to clear.
Step 1: Identify your hull shape
Our boat covers are cut differently depending on hull shape, so start by finding the closest match:
- Runabout — open bow runabouts and similar hulls
- Open Fishing Boat / Tinny / Dinghy — open aluminium and fibreglass fishing boats
- Centre or Side Console — console-steered boats
- Cuddy Cabin / Half Cab — boats with a small forward cabin
- Jumbo (T-top / Bimini) — boats with a T-top or permanently fitted bimini that needs to stay up under the cover
Step 2: Measure length and beam
Using a Runabout Boat Cover as an example, sizing is based on two measurements:
- Length — the centreline length from bow to stern.
- Beam — the widest part of the hull.
| Boat length | Beam |
| 3.6–4.2m / 12–14ft | 183cm |
| 4.2–4.8m / 14–16ft | 228cm |
| 4.8–5.6m / 16–18.5ft | 238cm |
| 5.2–5.8m / 17–19ft | 242cm |
| 6.1–6.7m / 20–22ft | 253cm |
| 6.7–7.3m / 22–24ft | 253cm |
Each hull shape and product page has its own size chart with the equivalent measurements — check the chart on the specific cover you're considering.
Step 3: Cross-check the actual fabric measurement
Centreline length and widest beam are a good starting point, but we recommend cross-checking against the actual fabric length and width required, since fittings add to what the cover needs to clear:
- Fabric length — measure along the length of your boat, over the top of any fittings (bow rails, handrails, cabin, windscreens, etc.) to the point on the hull where the cover's hem will finish.
- Fabric width — measure across the widest point of your boat, over the top of any fittings, to the point on the hull where the cover's hem will finish.
For a 3.6–4.2m (12–14ft) Runabout, for example, that works out to roughly 468cm of fabric length and 240cm of fabric width — noticeably more than the boat's raw length and beam, because the cover has to clear the fittings. Product pages list the equivalent fabric measurements for every size.
Step 4: Choose Standard or DuraPoly
Once you know your size, the fabric choice comes down to how long you need the cover to last and how you'll use it:
| Feature | Standard | DuraPoly |
| Fabric | 600D Oxford polyester | 600D solution-dyed Oxford polyester |
| Water protection | Water-repellent fabric | 1500mm water column + waterproof seam strip |
| UV performance | Standard UV protection | Extra UV inhibitor for better fade resistance |
| Trailerable | Low-speed, short-distance travel when properly tied down | Highway, long-distance travel when properly tied down |
| Warranty | 12 months | 24 months |
See our DuraPoly vs Standard Boat Covers guide for a fuller comparison.
Care tips that protect your warranty
Two things matter most for keeping a cover in good condition long-term:
- Pad sharp or protruding fittings (cleats, anchors, etc.) where the cover contacts them — damage from rubbing against sharp or raised hardware isn't covered under warranty.
- For long-distance towing, use extra straps (not included) over the top and keep tension even — damage from improper or loose strapping during trailering also isn't covered under warranty.
Full details are on our Warranty Information page.
Frequently asked questions
How do I know what size boat cover I need?
Measure your boat's centreline length (bow to stern) and beam (widest point), match your hull shape to the right cover category, then cross-check against the fabric length and width listed on the product page to be sure fittings like bow rails and windscreens are accounted for.
What if my boat is between two sizes?
Size up. A cover that's slightly larger drapes properly and is easier to secure; one that's too small will pull at the seams and be difficult to fit.
How is boat length measured for a cover?
As the centreline length from the tip of the bow to the stern (transom) — not including the outboard motor, which sits behind the transom.
Can I tow my boat with the cover on?
Standard covers are rated for low-speed, short-distance travel when properly tied down. DuraPoly covers are rated for highway, long-distance travel when properly tied down. Either way, use extra tie-down straps for towing, since strap-related damage isn't covered under warranty.
What's the difference between Standard and DuraPoly covers?
DuraPoly uses solution-dyed fabric (better fade resistance), has a 1500mm water column rating with waterproof seam strips, extra UV protection, is rated for highway towing, and carries a 24-month warranty — compared to 12 months on Standard covers.
Browse the full range in our Boat Covers collection.