AvidJack

Oops- missed it.  You're looking for an inboard mount. You might try and contact Don- he had a thread under catalinas (don's catalina), and had moved his sponsons iniboard as well.  I only have the one jury strut- he had two, and moved it in to the outer of the two (yeah, it reads confusing to me as well, but there are pictures in the thread..) 
 
Jack
Austin, TX

I made the change.  I'm not that great a welder, so I bought a 1" tube (whatever the width of the float is), and split it where the float flange is, bending it down for a hole, and a bolt mounting point on the float.  I also drilled through the pipe with a hole saw for the vertical mounts- and since I pinned them with bolts, they are adjustable.  It looked to me as though the nose needed to be down a bit on the lotus floats, and flying found that to be the case- Not a great picture- but it's on this site: 

If you zoom in on it, you might be able to see what I did.  The little red dot at the tip is an aerodynamic touch- a superball ground down to fit.  Note the nose of the float is still a bit high.  I brought is down a bit more after this flight- as per the tufting.
Jack
Austin, TX

Cruising speed is still around 75, but I can push it on up to 90+ straight and level.. and burn lotsa fuel.  I have a fuel flow gauge, and try to keep it down around 5.5 gph in cruise, full throttle is more like 11. There's a LOT of drag in the design, especially as you push it faster.  I do use the water rudder when it's windy, it's hard to turn against the wind without it, even dragging an outboard sponson isn't enough at times.  I don't hook up the control rod from the tail unless it's windy (that picture was an early one- the rudder is now installed).  Of course, landing will be rough when it's windy.. go for the lee.  I have nickle edges on my prop as well, but was shocked at the amount of water going through the prop in rough water plow taxis (camera footage), so avoid that whenever possible when rough. It was even taking the paint off- my tips are no longer painted. One note of caution, it's possible  to bring up the rudder and have it on the outside of the control rod, which then limits your rudder travel.  If it doesn't come up right (takes extra oomph to try and seat it), drop it back down, center your rudder, and try again. 
If  you're really far forward CG (you've seen my W&B), you might cast some lead into a split shape that might easily fasten onto those handles at the rear when needed... a little lead that far back goes a long weigh (some pun intended)?

So you went and did it?  Congratulations!  At your weight, I can imagine that it would fly off pretty quickly.  I weigh 195 and, as mentioned, I attach a 25 pound barbell weight to the floor on the passenger side of the plane to give me more forward CG when I fly solo.  When I have a  passenger, I can remove it. It's nothing more than a pipe flange, a short nipple, and a cap. The pipe flange stays, and really isn't in the way.
My first flight had the stick pretty far forward as well, I just adjusted it back a bit. And, yes, with all that wing and lift, first takeoff surprised me too!  I hardly use any trim at all, don't really need it.  I worked through the weight regime by flying with Mr. Sandman.. a waterproof duffelbag with first one, then two 50 pound sacks of sand, augmented by additional barbell weights along the way. I do find that the forward CG positions (at gross) do tend to become hard to perform a full power-on stall, but have little issue with power-off. And, if you want to practice engine-outs, what better place to do it than over a large, empty body of water?  I did one BFR in the catalina, and when the instructor asked about engine outs, I demonstrated one.  I believe it was the first time she'd aver done a *real* engine out...
If you change the horizontal stabilizer, do it one washer at a time- a little bit of change goes a LONG way!
While the other is an earlier picture, you can see on zooming in on the trim tab that it's just barely deflected upwards- I do not trim for landings, I prefer to hold pressure, and not mess with re-configuring if I need to go around.
 
Have fun!

Or...this one (Jim Chuk sent this to me, a while back...)
 

are you looking for this?  This is what i put on my Catalina- I think they're still available from kitfiox
 

 
Jack

Yes, that's mine/me on youtube "Lake Granger Splashin".  I've taken rough water videos as well, but it's a pain to find "public domain" music to go along with it all.  While building, I tried to capture every picture I could of other catalinas/amphibians/landphibians,and some of them saved a lot of head-scratching.  One thing I've noted- Not one catalina has done their gear lock/unlock the same way.  I'm still working on that one- I can lock wheels up just fine, but there have been a few "button pinching" episodes trying to get the gear back down.  I just made another mod- hopefully it'll be better. At the end of almost every work session, I took pictures of what I'd done that day, so if you want... 
  Mine was a project started in 1992, and donated to a Civil Air Patrol  squadron, where it sat and lost parts, and was then auctioned off, and stuck in a storage room for another ten years, losing parts along the way (my center gas tank is in the catalina in Forth Worth- the blue one).  Mine came with the Hirth F30, purchased from the original distributor, Falconar in Canada, and they'd set it up with a dynafocal mount.  It also had one of the VERY first NSI gearboxes.  I hated scrapping out a zero-time gearbox.
I used aircraft birch the same thickness as the originals for the finger ribs. I'd had a few tails lost on mine through the storage years, and had already made a few replacements.  The leading edge ply (1/32) is also aircraft birch.  The plastic leading edge I bought from Steve Winder back when-  his comments: "The Plastic Leading edge cuff DOES Work.  It "sharpens" the Front Spar Radius which helps reduce stall and improve speed. Every little helps on a slow draggy airplane...like Avids."  It's the same used for the kitfox, but if you go with the Riblett rib the profile already incorporates that, and more. 
To secure the leading edge to the finger ribs- I cut an outside clamp for gluing. you can just make out the foam between it and the leading edge.  You can also see how I clamped the  extra finger ribs- no tail needed.  There was a lever effect- pull down the tail with the leading edge ply already secured, and then temporarily tie the tail using safety wire while the thickened epoxy set, and cut 'em off later. 

Incidentally, those HF bar clamps work pretty well for gluing- if you try and tighten them too much, which would cause a glue-starved joint, they break.  But- they have a lifetime warranty- keep your receipt.
Here's another thing you might do while the wing is open-I ended up putting my comm antenna out on the wing, over inspection plates for the pitot. Please, if you don't have it, put in a combination static/pitot.  I could *never* find a good static spot. Anyway- looks pretty iffy before covering, but I've talked 40 miles, using an Icom A3.  I'd also run a thin pex tube to the wingtip to run your nav light wires through if you use them, that way, if something happens in the future, they're a lot easier to replace.

I used Smiths CPS ( clear penetrating epoxy sealer) to prime all my wood- I first used it when restoring a large wooden boat,and became hooked.
 
-Jack

A bit off topic? I grew up on Texoma, on the border of Texas and Oklahoma, north of Dallas.  I've *never* been on the whole lake, not even a quarter of it- didn't have that much time, or gas.  I hope to fly the cat up there this spring, my father retired in the house we built together back in the 70's, and I'd love to fly in and surprise him.  The only problem?  The Catalina cruises at 70-75.  Given the weather in Texas, it might be a week long trip!.  I *really* like water ops- but it is, from time to time, a long haul to the *big* waters (hence the Osprey build).  However, there are enough man-made ponds (ranchers call them "tanks" down here) that I enjoy the sudden increase in really safe emergency landing spots.  I might get in safely, and trailer out.  Luckily, haven't had to test that yet, but there was this one buzzard..
And there are *still* bridges out in Texas from the floods last memorial day .  Dry, maybe, but not always!  Lake Travis was down 60 feet this time last year, and now it's only down 5!  If you want to know how quickly things change, this is a fun video- it starts out slow, but keep watching!  http://www.youtube.com/watch?v=6beJDUSSqqc
-Jack

Y'know, if the CPS wing tanks had been available at the time, I might have tried those out, instead of the full-lotus sponsons- empty, they'd serve the same purpose, and if nothing else, you could use them unplumbed to hold spare fuel (or?) for a long flight..?
Jack
 

Ok,  I screwed up... I was commenting on the wrong thread when I mentioned the wing tank level indicators.. They'll work just fine for an avid without a hull.  But- I do still recommend the fuel cutoffs.  Makes it easier to change a filter, and saves a lot of cursing when you park sideways on a slight incline with fairly full tanks.
$.02
Jack
Austin TX
Catalina N92KL (flying)
Bandit N220AP (flying, not my build)
Osprey II (60%?)

When it comes time to smooth out the tapes and runs, wherever you are in the polycoat process- there's a trick in the back of the Poly manual that makes everything work MUCH better.  Go get some Reynolds (tm) oven baking bags (Turkey are the largest), split them open, and use them between the fabric and the iron.  They allow you to stick down anything that is sticking up, and even fair in a lot of the edges of tapes, using the excess polystuff.  I've even ironed out the next-to-final paint coating.  Iron it out, let it cool, and peel it back off- it's now smooth (NO sanding!).  If you split one bag in two, you can iron on one while the other is cooling..
I used a harbor freight HVLP paint setup, about $99 (Item #44677). that is self-contained to paint several aircraft. Polyspray and Polytone are pretty forgiving if you don't stop in the process to admire your work.  Pick a calm day that's not too buggy, and shoot- I did two planes in the carport.
No, I'm not connected with Harbor Freight, but I do have one of their portable garages that I've used in the past as a paint booth.  I even borrowed my dad's HF hvlp (above) and used it as an air supply to my hood (located outside the HF garage) when I was shooting epoxy primer with mine.
And- one more thing while I'm at it.  I do NOT recommend the fuel indicators that you are using in your wing tanks,  I went ahead and put in capacitive probes and panel gauges.  Sit in the plane, and you'll see that there's NO way to see the pilot side wing tank.  I also put in fuel cutoffs for both wing tanks (before the filters), not hard to do.  When you park on a slight slope, all the fuel drains over to the low tank, and can leak out.  I simply shut off ONE tank when parking, and fly with both open.  If one starts to drain faster than the other, I can feed off the fuller tank for a bit.  It's so much easier than trying to fly with a wing held low, for a cross-feed.  In any other Avid- they're fine- I have see'um windows in my Bandit, and they serve well, but not in an amphibian or catalina.
$.02
Jack
Austin, TX

 I recall reading correspondence between Riblett and an avid owner, where Riblett discussed the modifications that might be made to the existing ribs, by applying material to modify the existing ribs.  Seems as though there was a flattening of the bottom, and a change and extension to the leading profile..?    I'm 99% certain that the "newer" kitfox ribs were the riblett design. The twist in the elevator on my cat is, as I recall, quite substantial.  I'm running a Hirth F30 swinging a three-blade warp drive prop, and I can really tell when I hit the drag curve-  more power==more noise, and not much else.  I can also tell when I'm even a half degree out of pitch on the prop- getting over the hump can get exciting. I can take off the water at 1250 lbs with my current setup.
I did use the plastic leading edges on my cat to reduce drag a bit.  I also have a pipe wall flange on the copilot side floor, pretty far forward. When I'm alone, I use a short pipe nipple and cap to secure a 25 pound barbell weight for ballast.  That way I can remove it when I'm flying pax, and they can sit up front.  I sat in the back once, and would never force anyone back there!  I also registered as a two-place, and placarded as such.  I'm 6' and 195, and even the front pax seat is cramped for me. And, since I fly sport...
I  changed to the full-lotus sponsons.  They saved me around 8 pounds, and I *think* they're a bit more aerodynamic.  I haven't finalized the mounts yet, as tufting indicated that they're still a bit high in the front.  I used a 1" diameter tube for the attach- I split it to form tabs for the sponson attach points, and stuffed a small "superball" in the ends. The pic earlier in this thread is the one I used as a template, and I've already extended about 2 inches down in the front, with probably another inch to go.  Here's a picture of that::

And yes, I still have fairing to do-  in this pic you can see an experiment, which I'm not quite happy with yet- monokote. .  I simply glued a paint stir stick to the back edge of the sponson support, and wrapped monokote around the lot and shrank it tight., just to see if it would hold up.  Thus far, it has, and I may do the rest of the unfaired tubes in the same manner.  I'd also used monokote to cover the strut fairings-  It was my first attempt using it, and I highly recommend buying a heat gun that has multiple temperature settings if you go that route, as quite a bit of shrinking needs to take place, and an iron just didn't work for me.  You might say working with monokote was a whole new wrinkle?  And- I struggled with where to and how to mount the transponder antenna-  this seems to work ok for me, and is easily serviced!
One more thing I did, and would probably not do again, is use the optional leading edge- a strip of thin material to better form the wing profile.  The manual called out aluminum, but to avoid oil-canning, I used plywood- it still oil-canned *after* I'd covered and rib-stictched, and done the second shrink.  I had to add additional finger ribs to strengthen the profile.  I *really* hated cutting off all that fabric, and in retrospect, while I probably gained lift, I probably increased drag at the same time.   If you fair out ( using epoxy and microballoons- slather the stuff on, then stretch saranwrap over it.  you can work out bubbles and voids with  your fingers (and a pin)  if need be, and it greatly reduces the sanding required.  This picture shows- the leading edge strip, the attached plastic leading edge and fairing in the gas tank (using saran wrap) before the pin was used to pop those bubbles.

Jack
Austin, TX
 
 

If you're talking about the wing tanks on the catalina, I had the same concern, and drilled and tapped mine to a larger size- I'm thinking 3/8"  There's an aluminum plate buried in the fiberglass on my tanks (125AB) around the outlets,  which came as a relief.  I *carefully* drilled and tapped mine with NPT threads, which had NOT had any fuel yet..  I don't have a center tank.
 
Since you've fueled yours, I'd ventilate it for a while- maybe a LONG air hose running off a compressor at 5-10 PSI for a while..  before messing with anything like drilling/tapping/making sparks.
 
I *think* I sealed threads with permatex #2, build logs are alsewhere.  No leaks thus far.  I used the smallest  strainer I could get from AirCraft Spruce.  I also set up shutoffs for each of the tanks prior to the filters.  Had fuel running out of tanks too often in the MK IV when parked on uneven ground, or when folding wings.  I tested at 12 GPH on each tank, and run both open when flying.
 
I also sat in the plane, and installed fuel senders when I realized there was no way in heck I could ever see the fuel level on the left wing root through a "window".  I used the falcon capacitance senders and gauge.  I also modified the murle williams header tank with low-fuel warning, and installed it behind the third seat on the pilot side- I have a Hirth F30, which has a fuel return from the mikuni SBN carbs with built in pump and regulator (as well as an an-line facit, which helps prime and clear air), so needed a place to return fuel.  Warning light gives me ~10 minutes of time to panic..  as well as a quick reminder should I be so silly as to attempt a takeoff with both tanks off.  It also acts as a gascolator to catch water- which I thought usefull in a seaplane.
 
If you do set up dual shutoffs to tanks, I only close one valve to prevent cross-feed when parked.  To shut off both might create a pressure issue, depending on where you plumb in your vent line (mine has an on/off valve).
 
$.02
 
Jack
Austin TX
Catalina 125AB  Hirth F30  (27.5 hrs)
MK IV/Bandit  Jabiru 2200