What color?

If you're using MM Acryl:

Intermediate Blue FS35164

I don't see Dark Sea Blue available in the Acryl line, but you can go with MM Enamel Dark Sea Blue FS15042. Or Tamiya XF-17 Sea Blue.

Thanks Doogs, I'll pick up some enamel for the dark blue.

Be advised that Dark Sea Blue is a glossy finish (hence the FS number starting with "1")... Most TBMs didn't get finished in Dark Sea Blue until VERY late or after the war... Most retained their three-color Non-Specular Sea Blue/Intermediate Blue over white schemes until after the shooting stopped, unless they were delivered from the factory in overall Dark Sea Blue...  Most Avenger squadrons simply didn't have the time (Due to the high OPTEMPO of those units) or materials to repaint the planes while deployed.