Bedding for window

[chill]

I am currently building a Woods catamaran.

I have a series of plexiglass windows that are to be installed on the cuddy.

What would I bed the windows in ?

[John Blazy]

A new low cost, yet very high performance sealant is out now on the market that is a moisture-cure urethane and has the elasticity of silicone but higher adhesion to porous surfaces, yet is paintable and won't contaminate any future paint job.
Called PL Polyurethane sealant, it comes in black (called 'roof sealant'), white and brown (window n door sealant), as well as a cement patch sealant version that is concrete color. All the same, just different colors.
Get it for less than five bucks a tube at your local home center - plenty as good as 3M 5200 or 5400.