Though not Boat related will pass on my experience. 1+ year, Costoco Nitro in tires on 3 cars. Need to have them top off at Costco (they said a little 'air' was OK, but if too much bring them in and they will empty the tire and refill fresh with Nitro). Have had one tire on two of the cars become low and needed more 'Nitro'. Other tires held their pressure just fine, even over the winter / summer. (Prior when using 'air' I would check and top off tires a couple of times a year using my home compressor). So bottom line: It does seem to prevent 'normal' loss of pressure. But if you have something else going on (like with my two tires that dropped to say mid 20lbs), it will not stop that. -al-