Frustrated

[siberianhusky]

Ditch the water pickups right away, buddy of mine had a mono with serious running issues, had a pair of underhull pickups hanging down too far. Tried everything to stop it from running wet (slow) as soon as he got rid of the under hull pickups ALL handling problems went right away.
You also need to find a hobbyshop where they have a clue about boats, that guy who set you up evidently just wanted to sell you stuff.
Rudders with the built in pickup are about the best/simplest method, been used for decades because they work and work well.
I'd just cut and file off the skeg, no need to buy a new one.
I'll bet 95% of the problem is the water pickups, the drag is forcing the nose back into the water, just like a set of trim tabs.

[robbo1]

I'm in the process of fixing all the issues with my apparition. I've removed the sponson water pickups and going to use a rudder with dual water intake. I'm also blueprinting the ride pads as I have severe rocking… this is where the problem lies: I cannot remove anymore material from the front ride pad to allow it to sit flat as it has gone down to the fibreglass. So do I build up the other ride pads with filler until the rocking is eliminated?

[Luck as a Constant]

I agree about your water pickups being to low, however, I don't think they're useless. I keep mine so the tip is like 1/8 in the water. Barely any of it, and it flows water like a hose. Most people think it needs to be deep like that when it barely needs to touch the water to work


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[robbo1]

I'm in the process of fixing all the issues with my apparition. I've removed the sponson water pickups and going to use a rudder with dual water intake. I'm also blueprinting the ride pads as I have severe rocking… this is where the problem lies: I cannot remove anymore material from the front ride pad to allow it to sit flat as it has gone down to the fibreglass. So do I build up the other ride pads with filler until the rocking is eliminated?

[tlandauer]

Is the front pad in the water when running WOT? The important area (pads) are the ones actually RIDING on the water. A good riding CAT should have the front pads clear off the water. The rear pads should not have any rocking. Put them on a glass top and also check their profile.
To answer your question, YES! And you need to patch up the one that's been thinned down to just FG by adding a layer of FG clothe inside---that's what I have done on my cats as well as mono's ride pad near the transom.

[robbo1]

I can't be sure if front pads are in water or not as I've never had the boat running correctly. All I know for sure is when the boat is sitting on a flat surface the right rear has a gap of 3 millimetres as does the middle ride pad on the same side in comparison to the opposite side. Also the profiles are all over the shop, I suppose they all need to be true.?

[f1rogers]

just curious on the electronics it takes to make that 32" cat go 75mph on 4s. thanks.

[BHChieftain]

What about the short piece of heatshrink sealing the stuffing tube to the strut? I tried that a few times and it seemed to me to add a lot of drag. Someone gave me advice to run a longer piece of shrink to cover the entire stuffing tube (to avoid the "lip") or to ditch it (I ditched, as my water intrusion at that point was very minimal).

Let me know what others think about that...

Chief

[robbo1]

So blueprinting of the ride pads is almost complete with almost all rocking eliminated. My question is: should I be seeing any light at the rear of the centre pads, or should they be touching when the cat is placed on a flat surface?

[robbo1]

Hi folk, time to report back after a long while. Ride pads blueprinted, sponson water pickups removed and replaced with dual rudder pickup, new stuffing tube bent correctly and strut flat, sitting 3mm above sponsons. Top speed of 63mph with m447 prop… 20mph faster than previous.… beyond comparison! Not so frustrated anymore! Next is a m645, not sure if I'll be pushing close to the limits of components or if this prop will give much of a speed increase in comparison to the m447…. any thoughts?

[SpartanDriver]

Personally I would go with a M647 and call it you will get a little more bite in the water if you compare the the pitches you will see not much in the cup depth go the next size up, what you are doing I did, a ton of props every where.
The M647 just may be you top limit unless you redo the setup with different motor esc and batteries. But this hobby is just a water swirl with no bottom lol,
Happy boating my friend

[Tamelesstgr]

Outstanding feeling when all that hard work pays off, congrats, I learned quite a bit of info in this thread.

[electric]

What about the short piece of heatshrink sealing the stuffing tube to the strut? I tried that a few times and it seemed to me to add a lot of drag. Someone gave me advice to run a longer piece of shrink to cover the entire stuffing tube (to avoid the "lip") or to ditch it (I ditched, as my water intrusion at that point was very minimal).

Let me know what others think about that...

Chief

I put the heat shrink on some of my hydros (if I remember to do it during the build). Here is my logic. The lip of the shrink is less than the lip of the strut where the tube goes into it. How could that be worse? Secondly, it prevents water seeping or flushing through the strut at high speeds. Not saying that happens all the time or anything, but maybe a good insurance policy. Not sure if my thinking is correct, so I would invite comment on that topic as well.

[electric]

just curious on the electronics it takes to make that 32" cat go 75mph on 4s. thanks.

Jay(Fluid), is the guy to answer that. The short answer is I believe it should be doable on 4s2p. We have 4s oval race hydro's that can go 65mph. It's all about Amps, Props, how much hull is in the water, but I would think it would be doable for sure. Since your limited on volts(14.8) you need a lot of amps(really good ESC) to generate the horsepower. Watts = Volts X Amps. Helps to have a very efficient motor that is not wasting energy on heat. Neu or Lehner come to mind. Etc...

As you prop up to get to 75mph, you have to deal with the amps going up(think 170 - 240 amps, or more..), controlling the heat, short wires are required(resistance), blow overs, really great props...

So many variables to work on, which is the fun part of the hobby. When you have it all just right you get 75mph and nothing blows up, melts, or otherwise self-destructs...easy stuff...haha

Most people, including me when I started this hobby, are looking or definitive list of things to buy or install to go fast. Even if you get a "list" from someone there is still a whole other set of variables to deal with. COG, HULL, Strut Angle, drive line, rudder depth, sharpness, shape of rudders, etc. So two boats with the exact same set up may have a 10mph or more variance. Enough to drive you crazy.

[Commotion]

This is my apparition some years ago. I put a cheap 3660 3180kV motor in it and offset the rudder. I also put an unknown Cnc ally prop on it. I was running 4S but I now know the packs were massively underrated. I think the prop was too big as those volts and that kV motor should have been pushing > 50k rpm. It kept desoldering the connectors on the 120A ESC. The boat actually stopped dead in the water with the connectors completely unsoldered once. There was melted solder sprayed inside the hull. I thought I did a bad solder job but it kept doing it. Years later the batts have now puffed and I have put the original 3660 motor from my pursuit in it. I think i cooked the 3180 motor as there is minimal cogging so magnets seem stuffed. I was pretty inexperienced and glad it didn't all end up in flames.

http://youtu.be/_FVw2v-PKeM