Make These DIY Cockpit Scupper Grates


I have a serious mental condition known as OCD, Obsessive Compulsive DIY syndrome. I see something that needs fixed or replaced and I ask myself, “How can I make that?”

The other night, I had an OCD attack and I just needed to go out in my shop and make something with my hands. It was one of those days when nothing else seemed to go right. For me, it’s cathartic to turn raw materials into something practical and/or beautiful.

I decided to make cockpit scupper grates to replace the flimsy, afterthought-designed, original grates. They were corroded, bent, and wouldn’t stay glued in place for long.

BEFORE - Like an old bathtub drain
BEFORE – Like grandma’s bathtub drain

About an hour later, I had shiny new grates that look like those sold by a popular online Catalina parts retailer but they cost me next to nothing. I made them out of scrap aluminum plate that I had leftover from a previous OCD episode when I made my own mast gates. It’s 1/16″ thick 6061 alloy so it’s harder than your average aluminum but still easy to work with using common power and hand tools. You can buy common aluminum stock at many hardware stores. If you’re up for a bigger challenge, try making them out of stainless steel if you can get it. I polished the aluminum with a buffing wheel until it looked like polished stainless steel.

No design skills necessary

I had already made a 1:1 scale drawing to use as a pattern for the overall shape and the hole layout. If you’re a follower of this blog and have the current password, you can download the drawing from my Downloads page. To become a follower, just use the Follow button in the right sidebar to send me your email address. Then you’ll begin receiving my occasional newsletters with exclusive news, content, and offers just for followers. The password for the Downloads page is at the bottom of every newsletter.

Make them yourself!

You can make a set of these grates too with just a few basic tools. Here’s how:

  1. Print out two copies of the drawing and cut along the grate outlines to make templates.
  2. Use spray adhesive or double-sided tape to affix the templates to your metal stock like in the picture below. That will hold the templates in place while you mark and drill the holes.
Mark the hole centers carefully for the best results.

3. Use a center punch and hammer to mark the center of each hole. Center marks are already drawn for you on the drawing.

4. Use a drill press or a hand drill to cut each hole. Start with a 1/8″ bit for better accuracy than starting with a 1/4″ bit, which will tend to wander a little until it gets started, especially in hard metals.

Drill the holes in two passes, the first 1/8″ diameter, the second 1/4″ diameter except for the mounting holes at the corners

5. After you have all the holes drilled to 1/8″ diameter, switch to a 1/4″ bit and enlarge the drain holes. The three mounting holes in the corners of each grate stay 1/8″ diameter.

6. Remove the templates and use a countersink tool or a large drill bit to ream the burrs and sharp edges from around each hole.

Ream the drain holes so bare feet don’t get cut

7. Place duct tape over the areas that you need to cut out to protect the surface from scratches as you cut out the grates.

8. Re-position the templates by lining up the holes, and then trace guidelines around the templates onto the tape.

9. Use a sabre saw, jig saw, or band saw with a fine tooth metal cutting blade and cut around the guidelines.

Cut to rough shape and grind, file, or sand to final shape. Remember to chamfer or radius the outside edges too.

10. Smooth the edges and corners with a file, stationary belt sander, or whatever you have available.

Finished grates ready for mounting

11. Remove the old grates from the cockpit sole and clean the scupper cups thoroughly.

12. Center each grate over its cup and mark the locations of the mounting holes.

13. Drill 7/64″ pilot holes for #6 x 1/2″ stainless steel pan head sheet metal screws. Drilling the mounting holes this close to the cockpit walls will make the holes angle outward if you don’t have a right angle drill or adapter. Do your best to make the pilot holes as vertical as possible.

A right angle drill adapter makes drilling in tight spaces easier

14. Use your countersink bit or a larger drill bit to chamfer the edges of the holes to twice their diameter, about 1/4″ in this case. Relieving the gelcoat edges prevents them from cracking when you drive in the screws.

Chamfer all holes through gelcoat to twice their diameter to prevent cracks

15. Insert the mounting screws into the grates, turn them upside down, and press a small cone of butyl tape around the top of each screw. It will seal the mounting holes, which go completely through the cockpit sole.

Seal the mounting holes with butyl tape

16. Turn the grates right side up and drive the screws home.

The finished project

Bam! No more ugly, floppy scupper grates.

The Bottom Line

Suggested price: $22.95
$tingy Sailor cost: $0
Savings: $22.95


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10 Comments Add yours

  1. sailorpepe says:

    Very neat! I’ll be doing mine soon!

  2. Berny says:

    I’ll look at making them but I think I’d prefer to have them flush with the cockpit floor to prevent solids accumulating around the drain.

    1. I think that’s why the commercial ones have notches on the sides. It hasn’t been an issue for me yet, but if it becomes one, I will just modify them and update this post.

  3. Ben Rouse says:

    They look rather flash!

  4. sl duck says:

    I notice it looks like you use your table saw as a drill press table. Assuming you apply the same OCD thinking to your shop that you apply to your boat, I’d love to see a post about how you’ve arranged your workshop. I’m just figuring out how to lay out my small shop to do much the same type of projects you’re doing.

    1. I’ve had requests before about my shop, so maybe it’s time for a tour. It’s not high-end, but I’ve made and fixed a lot of stuff in it over the years. I’ll put that idea on the to-do list. Thanks!

  5. Tomas Kruska says:

    Very nice… one of those hacks I could handle too 🙂

  6. Culler says:

    I am very good at reading DIY projects!

  7. adamsboatworks says:

    A very cool and good looking addition to any boat. I am putting them on my list of things to do on my boat. Along those lines, do you have an article for enlarging the scuppers drain pipe size? While cleaning out the grunge of 2yrs under a tree with the hatch and companion way open, I sat there and thought about that and your blog. Not being one to want to reinvent the wheel so to speak, I thought I’d ask here.

    Thanks for your time and effort in keeping this blog going.


    1. Enlarging the forward scuppers would be a complicated project so some owners install larger ones through the transom instead, which eliminates the clogging problem altogether and speeds up cockpit draining.

      I prefer to just keep mine cleared. Whenever I’m hosing down the cockpit with a spray nozzle, I shoot a few seconds straight down the scuppers to flush out any accumulated debris. Make sure the through-hull valve is open, the galley drain valve is closed, and step on the other drain when you flush each. It helps that I can store my boat under cover too.

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