Hi All;<br /><br />Have a used Zodiac Futura MK II here..........<br /><br />I do not have an instruction manual. <br /><br />Can anyone out there explain to me the function of the 4 position "silver" inflation valves, one in each side tube ? <br /><br />and the inter-relation between these and the inflatable keel?<br /><br />I do understand how the "speed tubes" inflate<br /><br />I've done a pretty good Goggle and there isn't much on manuals, etc...........<br /><br />Thanks;