Tech: Making vessel registration letters

Working down my boat maintenance list, I had one more thing to fix before heading out. Arriba's vessel registration letters on one side were disintegrating and had become hard to read, not to mention ugly. The holiday period is not a good time for anything dodgy that might attract attention as the Water Police are always out in force  - admittedly mostly handing out citations to clueless jet skiers.

You can buy letters pre-cut vinyl letters in limited colors and sizes, but I thought it would be more fun to purchase a roll of vinyl and make my own. I could also ensure a good match with the existing letters. Here's the process:

1. Designing

The first step is to check your local authority for their requirements. For example, in South Australia, letters must be at least 150 mm (~6") tall and clearly readable at a distance of 50 m in clear weather. It doesn't state whether the reader needs 20/20 vision though!

The Google fonts website has lots of free fonts to choose from, although some fancy fonts, such as Tangerine, may not meet the requirements. I chose “Open Sans” in bold italics and I wanted the letters to be 158 mm (~ 6 ¼”) tall. The easiest way to ensure the correct height is to draw a vertical line with the desired height and increase the font size until the letter height matches. For Open Sans bold italic, 630 points did the trick. I hand edited the image in SVG format which you can see here, but you can use any image editor that lets you specify real-world dimensions (such as mm or inches). It’s important to set the image size to your paper dimensions, which in my case was A4, or 297 mm by 210 mm. At 630 pt font size there’s only room for 2 letters per page, so Arriba’s 6-letter registration ZY110S was split into ZY, 11 and 0S.

2. Cutting

The next step is cutting the vinyl. We own a Silhouette Cameo electronic cutting tool we use for arts and crafts. After a bit of experimenting we found that a thickness setting of 4 worked well for vinyl, as it cuts through the vinyl but not the backing paper.

Silhouette Cameo cutting vinyl.

3. Joining

Next, the 3 sheets are aligned and joined together. Painters masking tape works well and leaves minimal sticky residue behind. Tape only the top half of each letter and remove the excess backing paper from the bottom (shown below).

4. Applying

The final and critical step is applying the letters to the hull, which should be done on a calm day. First, clean the surface with a solvent such as isopropyl alcohol. Then position the letters, using extra masking tape if necessary to keep them in place. Next, peal away and cut off the backing paper from just the bottom half of each letter and affix the bottoms, one letter at a time.

One all bottoms are affixed, peal away the remaining backing paper and affix the tops of each letter, one at a time. Apply pressure to ensure there are no bubbles trapped under the vinyl.

That's it!


PS Happy New Year 2017!