Well that last post was helpful huh??? Without going into too much detail look at www.pontoonwaterglide.com
. A couple of the members on "Pontoon and Deckboat Magazine" www.pdbworld.com
(you might want to look there also for some good info) have installed them and really like the performance gain....and the owners are really nice people.
As said before a third alum. pontoon is very expensive and without lifting strakes on all the tubes you will still just plow through the water. The larger middle tube on the newer pontoon boats are for folks that pull skiers and tubers, lets the pontoon boat turn quicker. Good luck......