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Advice on Polymer and Airgator

O

Otis

Member
Thanks in advance for your replies. I have learned a lot just lurking for a few weeks so I thought I would jump in. Is polymere installation a do it yourself job? Is there anywhere on the web that has instructions? What is the typical cost for an install by someone else or an airboat shop?

I am looking at an old 15' airgator it has a 500 caddy direct drive. Would it be worth it to ad a reduction unit and if so is there one that bolts on without having to redo the engine stand?

Thanks for the help
Otis
 
Well you should get a few replies on this one but here is mine.

I dont belive caddy engines do well with reduction units unless you spend a lot of money upgrading the parts in the engine. The engines were not made to turn up high rpms. They develop respectable numbers at 3000 rpms.

I belive engine stand modification is required anytime you add a reduction unit to a engine.

You can install polymer yourself I belive classic airboats includes instructions when you buy it from them. It is a very boring job that if done wrong can be a disater in the making. I have done it and if I needed to would do it again but need to is the operative word there.
 
IT's not to bad it just takes time to drill,counter sink,and make sure the polymer lays flat. Make sure you use a 1/2 drill when tighten the bolts or you can rivit the polymer on .nut and bolt takes awhile and take 2 people
 
I called Classic Airboats and they were out of their computer drawn polymer installation guide. I ended up talking to the person who installs the polymer on their boats. He was a great help. I'll pass on what I remember of the process, but be sure to check this out with a professional who does it all the time. I have only installed polymer once 4 to 5 years ago.
Two of us installed polymer on a 13'x7' Airgator, bottom and sides, an early 70's model. I took us 13 hours (2days 8&5hrs) to finish the job. Talk to a few people that have done it before you do the installation and you will get their ideas and their tricks of installation. It is always easier to install polymer when it is hot and sunny and polymer conforms better after it has been sitting in the Sun. Install the 3 screws in the lip first (see below), and then let it sit in the Sun until it becomes easier to work with. This isn't necessary, but it helps. It was a pointer I received after my installation. A heat gun also works for conforming the sheet.
We used three drills, one with the countersink bit (a 12 Volt Dewalt cordless drill with two good batteries and one always recharging)(Classic sells the bit with an adjustable depth collar), one 7/32"?(ask Classic what size) pilot hole drill bit(we used a 3/8" air drill),and one (1/2" air drill) with the screwdriver bit for the 1/4" machine screws. You need the moderate constant power of a 1/2" drill to drive the machine screw down below the highest surface of the countersunk polymer and into the aluminum. START SLOWLY and increase speed moderately until the screw bottoms out. The 1/4" stainless machine screw is threading into the 7/32" hole in the bottom. It's better to use a least one cordless and you can also use electric instead of air tools (air tools are lighter and easier to use if available). The least amount of power lines the better because when you get the hang of it, tangled cords slow you down. Two cords aren't too bad but three get tangled too easily.
Mark the AFT CENTER OF THE STERN LIP OF THE BOAT (this is your starting point), and MARK THE CENTER OF THE POLYMER ON THE STERN SIDE AND THE BOW SIDE. Square the polymer sheet to the stern lip of the boat. DRILL THE POLYMER AND LIP OF THE BOTTOM OF THE BOAT, COUNTERSINK POLYMER AND SCREW IN A MACHINE SCREW. Mark the polymer with a Sharpie marking pen 1 1/2" on either side of your first screw, the center screw(The center screw was a starting point). Don't use the center screw to make a row forward . Use the two outer screws to start your rows.). Install two more machine screws. Now you have 3 screws in the lip of your bottom. Now you will want to make a couple of measuring guages. I used trim pieces from the polymer approximately 2" x 3' & 2"x10'. Mark the short piece every 3" for the edges of the sheet and the long one every 6" for the inside measurements of the sheet. Those two outer screws are 3" apart and from now on you measure and mark every 3" on both sides on each screw.The measurements on either side of the center screw will be 1 1/2",(then add 3" each measurement out) 4 1/2", 7 1/12", 10 1/2", 13 1/2", 16 1/2", 19 1/2", 22 1/2", 25 1/2" 28 1/2", 31 1/2", 34 1/2", 40 1/2" and so on until you come to the third to last row, then you split the difference between the third to last row and the outer row to make the second to last row of screws. These measurements are for marking your drilling pattern. We spaced the screws in the center of the sheet 6" apart. You can now start marking your drilling pattern fore and aft by starting with the center mark at the bow, and using the same process of measuring from side to side. Now that you have both of the sheet ends marked, the fore and aft lines can be drawn and the drilling marks marked. We didn't mark all the drilling point grids at one time, We just marked one or two rows at a time so as not to smudge the marker and have to do double work.
IMPORTANT !!!! Always work from the center of the sheet (boat) going out towards the outside of the boat. Just start with your first 3 screws in the lip (don't use the center screw to make a row), finish those 2 rows and install a screw in the lip when you begin your next row. When you work this way the sheet is conforming flat to the bottom of the boat and you won't create highs and lows in the sheet. Trim the sheet as needed to conform to the bottom the way you want it to finish out,(need a carpenters plumb, skill saw and a 2x4 to put between the boat and polymer),this can be done towards the end or in the beginning and make allowances if you plan on installing side sheets. We also staggered the bolts from row to row. When you start a row, measure one row 3" from the lip screw and the next row measure 6" from the lip screw. If done this way you will have a closer pattern of machine screws and a tighter fit.
I would try the polymer before you modify your engine. Polymer and a good composite prop will surprise you ,and you might want to leave it as a direct drive.
I hope this helps and make sense. I stayed up way too late trying to make sense out of an old project, but it was fun.
 
classic told me that they put 360 screws, bolts,in a 5 by 10 sheet of polymer 2"apart on the edge
 
RJ - Thanks for that post. Took some time to write that up and post it.
We sure appreciate it.

The aircraft industry makes rivet fans that expand to measure different distances between each point. You can measure 1/2, 3/4, 1 inch by quarter inches up to about 2 1/2 inches. Lays things out perfect and true for those of you that want engineering perfection. Skip every other tip on the fan and you can increase the spacing. Makes layout work real slick.

A heat gun can be of assistance on cool days, but a hot summer day works best.
 
Otis, If memory serves me correctly, when you buy the materials yourself, it will cost you around $400, maybe a little more. 5'x10' polymer about $180 each ( 2 sheets). Some airboat builders carry larger sheets of polymer so you won't have to splice the sheets, a good idea. You will have to ask around about that or look on the web at some of the builders part sites to find the larger size. I have seen the larger sheets advertised on some of the sites, but I don't remember which sites. Counter sink and drill bit about $25. Machine screws around $40.

I had a builder install the bottom and side sheets on a 13'x7' Airgator 3/16" bottom 1/4" grey polymer. I installed it on a 1/8" bottom, probably the same size bottom you have if it is an older boat. 5 years ago he charged $ 1400, $1000 for the bottom sheet and $400 for the side sheets.

Good luck with it. It is a fun and worthwhile project.

Marshmaster Pat, Good tips about the heat gun and the aircraft rivet fans.

If others have installed polymer, it would be helpful, interesting, and informative to hear some of your tips.
 
FOUND THIS ON AIRBOAT TRADER THOUGHT IT MITE HELP

1/4" 72" WIDE BLACK POLLY AS LONG AS YOU WANT,GUYS NAME IS LARRY YEAGER,PHONE#352-212-7182,EMAIL ADDRESS LARRYRYEAGER@WEBTV.NET HE IS IN INVERNESS FL
 
real polymer only comes 5ft by 10 ft here is the web site for polymer http://www.polyhisolidur.com plastic comes what ever size and shape you want and It only lasts one or two years poylmer can last 5 to 10 years depends on how you ride talked to most of the airboat shops and they all say the same thing.
 
Some people decide to put lock nuts on the inside of the hull. If you are running heavy marsh grass in Louisiana in places were storm debris may have washed up, or if you are going to be running over any rocks larger than a kid's fist, you might think seriously about using lock nuts on the inside. I have seen rocks pull machine screws lose. But this adds some costs and time. And it also hurts like the devil if you fall on those lock nuts.

Hint: foam ear plugs will fit perfectly into those machine screw holes if a screw comes out and typically last through several hours and maybe even a weekend of running. So that is another reason to carry spares. The foam rubber type seem to stay a little better than the cheaper foam ones.

Rivets work really well for holding polymer with little chance of pulling out. Installation however takes some time and practice. Once you get the feel of the job, it goes fairly fast. When driving rivets hit them with as short of tap on the trigger as possible. Have the backing weight held flat for the first tap, this will expand the rivet. Have the backing weight held at about a 30 degree angle for the 2nd tap. This will cause it to swell slightly sideways and totally fill the hole. Tap it one last time with the backing weight held flat again and the rivet should mushroom nicely. A good quality air hammer will work just fine instead of buying one of those high dollar rivet guns. A 2 pound sledge hammer head works great for a bucking bar or backing weight. And good earmuffs are needed.
 
cchardt,not true!polymer can be bought in any size required.i work in a ship yard and we use alot of polymer for a wide range of things and if it only came in 5x10 sheets it would not be practical for our applications.the only reason i can see for airboat shops to sell it in 5x10 sheets is so you have to buy 2 sheets to do the job right.heck i`d rather sell you 2 sheets of 5x10 for 149ea. verses 1 sheet for 189.00 thats 7x14,you make more money there way :lol:
 
well went to the polymer web site and looked all they advertise is 5 x 10 sheets also been told that you can but it in rolls and have not seen it yet. sure would be nice to buy one sheet to do the bottom of my new boat.
 
American Airboats advertises they use one piece polymer on their boats. Maybe they could tell you of someone closer that may also carry the rolls or larger sheets. I've got a new boat being built---I'm going with slick bottom this time.
 
Harvey is right, American does have it in rolls. I think I have seen it in 5 feet, not sure if they had it in 6 feet wide rolls. The rolls were probably 25 foot long (I am GUESSING) but it was plenty. They mostly rivet it on.

I have seen some wider boats there, and I don't recall seeing seams.

Get their number on their website and call them.
 
Well I've been on the phone today to the people that make the uhmw dk gray,black,white polymer. I'm tring to get better prices than the airboat shop. Ask the guy driect and he said that they only make it 5 x 10 sheets only, thats how big there dies are they don't make it by the roll.
 
CC- There must be more than one company making the stuff. I will ask the guys at American. Maybe more than one sheet was in a roll and I didn't notice. But looked like quite a bit more compared to the rolls I have seen.
 
KING PLASTICS in venice florida makes a white polymer and is very familiar with using it on airboats and it holds up in the sun real well I left some laying out for two years in the sun/shade and even washed off the slime several times a year so the sun could get too it and it never cracked and was just as slippery as when I put it there. They told me once if you bought a lot of it then you could get it bigger sizes probably a roll of it but their main run is in sheets. so you might look them up on the inet.
 
Not sure where your located at, but I bought a piece of black UHMW polymer that was 15x8 at Silver Dollar Airboats in Oklahoma for $500. I watched them cut it off of a huge roll. I called everywhere to try and find it and could only find 5x10 sheets.
 
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