Check out
this site. Just enter your surname in the box and click Go. The graphic you get is an ideal size for adding to a ship texture, just have to turn off javascript or do a screen grab to save it.

Also try it with and without capitalizing the name, sometimes that gets slightly different results. A friend of mine is descended from Clan Murray of Athol in Scotland. The critter on their crest is a mermaid and the motto is Tout Pret. But enter murray and it pops up the same shield but with a griffin and a motto of Imperio. (That the coat of arms of Those Other Murrays Over There.)
The one for my surname is a simple pair of black (sable) chevrons on an argent (silver or white) field, as seen on my little addition to what I'm working on here.

The critter on the nose is a cockatrice, similar effects as a basilisk to those unfortunate enoug to endure its gaze.

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