BBY Scat Cat 26, need help with set up

[TXTRCR]

i bought a scat cat 26 hull its un joined and unpainted and not cut out yet so all my options are open as far as hardware and electronics. I sent an email to chris at finedesignrc.com and he said for a good performing setup for bashing mostly he would go with a Cordite SS1 motor, Astro Flight 212D speedo, 12 3300 cells or more, fine design 8-16 cell hardware kit this comes with every thing but the prop. I dont have a clue what the numbers mean when it comes to boat props, will some one explain or at least tell me what props to buy for this boat with this set up. ill need a prop that will give the most speed the motor can produce with this setup for drag racing the locals at the pond and ill need a prop that conserves battery juice for longer play times, and a prop that will give a pretty good balance between the two. incase your not familiar with the hull its a 26 inch catamaran offshore race boat.

[Hydro Junkie]

Sorry I can't help you with Prather props, but when it comes to Octura, I have a little knowledge. With Octura, the number tells you the pitch and diameter of the prop in milimeters. The letter tells you if it's a lifting prop or not. For example, an X1445 reads: pitch is 1.4 times the diameter of 45mm with (if I remember right)lifting blades. They make 1.4, 1.5 and 1.6 series props, so you can play with your pitch as well as your diameter. They also make the "Y" series prop, which (again if I remember right) has little to no lift. If I go back to the example above, the prop is a 45mm with a 63mm pitch. I don't know if you know how pitch is computed, so if you don't, here's how it works; the pitch is the distance the prop travels forward per full rotation. So going back to the above example, the 63mm pitch will push the boat 63mm forward for each full rotation, in a perfect world. The boat's hull design, weight and engine power will effect how much of the 63mm you will actually get. Any loss is called propeller slippage, of which all props have. Your job is to find the props that balance engine load, lift and efficiency(the opposite of slippage) to get the most performance possible. Unfortunately, I have never played around with cats, so I can't recommend a prop. I hope this little "imprompto" lecture helps. I also hope someone can help you out with picking a prop and reading the Prather sizing codes. Good Luck and Happy Boating :D

[n.h.schmidt]

Hi I thought I would put in my two cents worth. Starting from scratch I would use a Graupner K 45 for general running and speed . One could also try a Graupner K48 for more speed but, watch out for heat problems. No prop work needed no ballancing or pollishing needed. Offshore Electrics can supply nearly all of the Graupner line of K props.
n.h.schmidt

[TXTRCR]

i think i understand now, im still a little unclear on how you go about choosing the right prop for the boat you have. isnt there a formula that i can use to determine which prop will provide the results i desire. im going to use a direct drive system and i think the rudder will either be inline with the prop or on the left or right side of the transom. here is a pic of the hull im working with. http://bbyracing.com/images/scatcat26collage.jpg here is a link to the motor and speedo i will use http://finedesignrc.com/speedcontrols/astro212d.gif and the motor http://finedesignrc.com/motors/cor775.gif also here is the hardware kit http://finedesignrc.com/hardware/hydrohardwarekit.jpg i hope this helps i really need to know which prop is the right one for my boat, with my knowledge of boats as of now all i can do is buy a bunch of props and hope one of them works.

[MikDee]

Cats of this type, & size, usually use an X442, or X445 for run time, or an X642, or X645 for speed. Or, a comparable graupner carbon fiber K42, or K45 Just watch your heat buildup.

[TXTRCR]

i have new problems now, the strut and strut bracket included with the 8-16 cell hardware kit from finedesignrc is too short. has anybody ever built one of these boats, i was just wondering if i could mount the strut bracket really low on the hull and lower the strut to its lowest position.

[BoatDoc]

you may be able to call chris fines and see if he can supply you with a longer strut. maybe if you post a pic, some of the other guys can help offer suggestions...it's just easier if we can see it.

[TXTRCR]

sorry thats an even longer story, i wish i had the parts here now to take pics or try and rig something up, i kind of wanted to find out before i opened any of the packages if it could be made to work. that way i know if i should just send it all back or what. my luck with boats is horrible. ill tell you the whole story if you promise not to cry. ok i saw this hull on rumrunnerracings forum buy sell trade section. i emailed the guy and told him i wanted it he gave me a price i couldnt refuse. so i sent a money order he emailed a few days later and said that he had gotten the money order, then i didnt hear from him for like 3 weeks. i though i had gotten ripped off but it turns out he was on vacation. the hull arrived a week later. i found out how much it was going to cost to get the boat going so the hull sat for almost a year. just recently i got to work on it, i joined the hull sanded the hull and prepared it for paint. after i got it all painted it looked so sweet, then after the paint started to cure 2 days later spiderwebs started to surface. so i figured i would order the hardware and electronics while i got the paint worked out. monday i orded the stuff the guy emailed and said it would take 3 to 4 days to arrive. friday rolled around and still no parts, monday, tuesday, and finally on wednesday i get an email saying there was a problem getting some of the parts i ordered and the credit card didnt clear untill 3 that afternoon. so its sunday now and im still waiting on parts. i emailed Ray fuller and he tells me that the hardware i ordered is the same that he sales and his kit is 86 dollars instead of 136 dollars, but thats not the right hardware kit for the boat hull i have and he doesnt think there is a way to make it work. he suggests that i buy a longer strut bracket and strut, but i already have 400 dollars invested in this boat and a hardware kit that i cant use so why would i buy more stuff.

[BoatDoc]

that's a sad story. mine are usually similar...so don't worry! it takes me months to build a boat because i can't really afford to do it in the first place! if you bought your hardware from fine design, i'm sure that chris will help you out. he has a reputation to uphold! if i remember right, monday is usually the day that he spends answering questions on the phone. give him a call and see what he'll do to help. i called him just to order props and got a load of set up tips for a boat that i bought from someone else! and i know it's hard...but the postal service must have a policy of delaying hobby related mail...because i'm waiting on parts to get both of my rigger's finished (almost 5 weeks now). don't give up, persistence pays off!

[Hydro Junkie]

I think we all have similar stories to tell. One thing to remember is any parts you buy that don't work on the present boat may be usable on the next boat, and as many here will attest, there is always "THE NEXT BOAT". We boaters are a persistant bunch. If there isn't a boat being built, modified or repaired in "the shop", we aren't happy. There are several here that will agree with me on this, I'm sure. I have at least six boats in the works right now. Thank heaven my significant other lets me have my "toys" :D

[Chris LaPanse]

By the way, the X are low lift props, and they make anywhere from about 1.1 ratio to 2.1 ratio props. Also, if I remember right, the props that are just numbers and the ones that are in the V series are high lift props.

[TXTRCR]

Yeah the parts came in today. It looks like the strut and strut bracket are just long enough. now i have a new question as far as placement of the rudder. will it hurt the performance of the boat if i mount the rudder inline with the prop like within a few millimeters of the prop close to 1/8 of a inch away from the prop. should i mount it center or far left of the prop or far right of the prop looking at the transom of the hull here is a hull pic again. and a link to what the assymbled hardware looks like on a hydro, thanks.

http://bbyracing.com/images/scatcat26collage.jpg
http://finedesignrc.com/hardware/basichydrohardware.jpg

[MikDee]

With your rudder in the middle, you'll have the best turning capability!,,, but, you will lose some of the roostertail. The rudder looks abit close though, don't know if that will affect anything, I'd guess not.

[TXTRCR]

alright im so happy, i finally got the boat completed. all the hardware and electronics are mounted. I put it in a small swimming pool to test for leaks. I left it sitting for about 30 minutes then came back and it was still afloat with no water in the hull. I desided to give it a further test by pushing the rear of the hull all the way down in the water to simulate the rush of water that hits the back of the boat when you stop. just a tiny droplet of water came into the hull so i siliconed every screw hole and the seal around the rubber boot then tested again, no leaks at all this time. i will do the first run tomorrow. one question though if the boat is up on plane and full throttle and i just let off the gas will the boat flip because of the momentum. i have seen videos of really fast boats and they are just cruising along then you hear the motor stop and the boat either does a front flip or dives underwater. what causes this to happen. oh and another question do you think the motor on my boat will be ok without water cooling cause the mount i am using doesnt allow enough room to put a coil on the motor. I have a Scat Cat 26 with a 12 3300 cells a cordite sealed can SS1 motor, an astro flight 212d speed controller and the motor is spinning a Octura X445 as recomended by a few different people, the motor is turning the prop via direct drive.

[TXTRCR]

ok whats wrong with my set up, Scat Cat 26 hull, cordite ss1 motor spinning a octura x445 direct drive. powered by 12 smc 3300 cells through an Astro Flight 212d speed controller no water cooling on any thing. The motor is good for 10 to 16 cells. the speed controller is good for 540 motors all the way up to an astro flight 40 size motor and 6 to 12 cells. I went to the local pond and it came up on plane a little slower than i would have liked but rather quickly compared to all the other boats i have run. i did one high speed pass then attempted to turn around the first time i turned it to full lock and the boat spun. i made another high speed pass then turned again this time not turning the wheel so hard and kind of stepping out of the throttle just a bit maybe 3/4 throttle in the turn then back to full throttle for another high speed pass. i continued to explore the posibilities of this boat. and on about the fifth lap the boat did not power down when i went into the turn and when i came out of the turn i let off the gass all the way and the boat continued to run at full throttle. so knowing that the boat would spin out when i cranked on the wheel i continued to force it to spin out untill i got it close enough for my cousin to reach down and grab it. when i finally got it wrestled to the ground i pulled the hatch off and disconneted the motor wires then the battery leads and instantly checked for heat. nothing was even warm and there wasnt any burned smells coming from the hull. i left it disconnected for about 30 minutes while i got my nerves under control. then connected the motor leads back up and as soon as i touched the battery leads to the speed control it started the motor and ran at full throttle. i continues to do this even now. i tried different batteries, motor, reciever, radio, servo every thing i could think of. when i connect every thing like its supposed to be i get the motor running at full throttle and not responding to throttle inputs from the transmitter but full control of steering what gives.

[n.h.schmidt]

Hi
There is only one thing left. The Astro 212d. It has to be shorted full on. You may have to consider getting a new esc. It's a bummer .I know .Been there done that. At least you got the boat back in one piece. n.h.schmidt

[DLM]

One other item; is your rx have a bec or not.? Batteries play a role here. If batteries get weak, the signal doesn't get to where you want them to go so you don't have control of your boat. This happened to me yesterday and the boat kept right on going full blast into mud bank. It would be like not having your antenna not extended at all. My problem was i pickup the wrong 9 volt battery for power for my rx.

[DLM]

You need to put a push-pull Du-Pro switch to shut off power to rx.

[TXTRCR]

the astro flight 212d has a battery eliminator circuit so i dont need reciever batteries. I ordered an astro flight 207d speed controller which doesnt have a BEC so i will need to get a reciever pack and a switch. I am going to use an 1100 mah gas truck 5 cell hump pack and switch harness. hopefully this will cure the problem. i used one of these controllers before and it worked very well. thanks for the info guys

[TXTRCR]

the boat made it through a full run. But it handles poorly in all catagories. it doesnt plane out for about 20 feet or so if i work the throttle just right if i stab the gas it just cavitates. i have to slow down a lot in the turns. and when the boat gets up on plane it jumps wildly sometimes it rotates to the left and some times it rotates to the right when it comes out of the water. its so on edge that it looks like its going to flip. what is wrong with my boat or a better question would be what isnt wrong with my boat. what do i do to stop cavitation smaller prop or larger prop. and what do i do to make the boat stay straight and flat when it comes out of the water. where does the center of gravity have to be. my batteries and motor are mounted at about 30% of the hull length measured from the transom. also the boat will sometimes slap the water with its bow repeatedly.

[DLM]

First your info on depth of strut but i would lower strut about 1/8" and i would angle prop down a couple degrees. Then make you're cg at 32%. What this does is brings bow down with cg and angle strut down also brings bow down. Each boat is different and no two scat cats are alike. Do not go hog wild on changes. One item at a time. Strut first and try it then cg .

[DLM]

Your prop is way to close to rudder. There should be 1" from prop to rudder. The reason is your controlability like you mentioned. Also the rudder cannot pickup water cause prop pushes water away from rudder and you're cat goes where it wants to. i would use the shorter strut unit and lower it 1/8".

[DLM]

Go to BBY site and then links and then Wohlt's RC Boats. He has a picture of a 26 transom.

[MikDee]

All of the advice here is Good, also it simply seems like your CG needs to be forward a bit more, IMHO

[TXTRCR]

DLM that is either a SC 21 or 31, i have the 26 with the funky transom thats not flat. the sponsons extend past the center of the transom like this \_/-\_/ kindof. there is just no room for hardware. can i take the rudder bracket and some how attach it to the strut bracket so the rudder is lower in the water and in line with the prop about 2 or 3 inches behind the prop. will that hurt or help steering and stability. thanks

[DLM]

Question, how far is rudder to the left? My guess is 1 1/2" to the left. Next? is how far is the push rod from center of strut? Here's what i'm getting at, if rudder arm can be turned 180 deg. without making another hole , there is an answer. What kind of material is the extension made of? What is diameter of extension rod? Ok, here goes and bear with me; if the extension rod is 5/16" in dia., you can go to lhs and get srainless steel tubing at $4.00 for a foot. You put the sst into extension and drill a hole in both parts and say you insert sst about 3" and put a bolt thru and nut it. Next put extension and sst as close to strut as possible and if you can put it on top of strut, all the better. But in case you cannot, locate the rudder close to strut and back 2'. The reason i say 2' is water flows around item like strut and etc and flows back together in a little over 1". This gives rudder clean and clear water without a lot of disturbance from prop. I do all my stuff and am looking at your picture and using my experience to keep your hardware looking new. Don't make any decisions till you have thought it out.

[DLM]

Don't touch anything! Where your rudder arm and secure cap are, it looks like 1/2', what you do is put on tight fitting washers between arm and secure cap and drop it 1/4" and it will remain a solid unit. Now for push rod , it can be bent down at an angle and the flattened out to match your arm hole. you should be ok then except all the cats have there rudder on the right side. Jeff Wohlt has a simple setup but is smooth and efficeint.

[TXTRCR]

ok i think i may have just confused the heck out of you all. the pic i sent of the hardware setup is not my setup it was just an example pic to show what the hardware i am using looks like. this is not my boat either but it is exactly how mine is set up now, the hull is exactly like my hull only smaller i think but as you can see there is no room in the center of the transom for mounting hardware. http://finedesignrc.com/gallery/mhz2.jpg im going to try this set up tomorrow and see how it does. this is the set up that was intended for this boat hull by the maker of the hull. because the hardware kit that comes with the hull if you buy it as ARR is not exactly like this but really close i may have to move my rudder towards the prop as i have about 1 or 2 inches clearance between the prop and rudder. i still have not solved the prop issues though. thanks for all your help guys and you can bet ill be back in here tomorrow asking for more. thanks again you guys are tops when it comes to info.

[DLM]

I was scooping thru and ran across the same piture. You say your boat is smaller, well for a 32' scat cat, a 642 is fine. now it dewpends how long your boat is and if it is 24 or 26" long and on a 700-8.4 or one of those , a 637 is nothing to sneeze at.

[DLM]

Food for thought. Set your strut as close to the transom and like i described with the small area you have. Lay rudder pipe on top of strut and have your base for strut as low as you can and then measure what you need for lenght for 2' . The pipe can be cut so as to slide over adjustment of strut and pipe will go into hull and problem solved . Tomorrow , make 2 adjustments, strut lower and cg moved forward a 1/4" at a time! Let everybody know how you make out. Good luck!

[DLM]

Forgot, 1 1/2" between prop and rudder . The dog drive should be directly across from rudder blade and a hair forward from middle of blade! This way the rudder won't be affected by the prop as much! The water from prop goes backward, not sideways!

[TXTRCR]

should it be a hair above or below the center of the rudder blade looking at a profile view of the hardware. and you say the distance between the end of the prop shaft and the leading edge of the rudder is about 1 1/2 inches. well then my boat is perfect. im going to run it and see how it does. but i still need a different prop. see i asked earlier about which prop to use and the guys misunderstood me and told me to get the Octura X445 prop <~~~which is a good prop to use on a gear drive system, but im running direct drive so i actually need a Octura X442 or smaller. the X445 cavitates terribly on take off.

[TXTRCR]

also due to inexperiance and a missing instruction manual i got the hull a little twisted when i joined the two halves. if you set it on a level serface you can see that the sponsons are uneven on is 1/16th of an inch higher than the other and the tips of the sponsons are the opposite of the rear. this is probably the cause of the poor handling but there is really nothing i can do about it or is there. like installing a thin peice of plastic sheet to the sponson that sits higher then the other.

[DLM]

The more i look ,it looks good. The kind of twisted unit has some effect and you can't do anything about that now. Prop 440 is a good prop. N.H.Schmidt is correct as always and he said k-45 or even better one notch lower on mm. Offshore has props and Steve has those props without balance or sharpening. Lowering strut and moving cg ahead 1/4". Take a notebook and pencil along and a ruler and write down your changes so you won't make same mistake twice! Go have some fun!!

[MikDee]

To add to my previous post, from rereading your posts, along with checking CG, it sounds like your prop is a little too high, you might hafta drop the strut abit. As a starting point on a mono, using a strightedge, centerline of the prop hub should be even with the bottom of the boat, prop 1/2 submerged,,, I would think, on a cat, that it also should be 1/2 submerged from the lowest part of your hull at the transom, checxk this out with a straightedge.

[DLM]

Forgot, get hold of Randy Naylor for the instruction manual and tell him you will pay for it. It will worth its weight in gold!

[DLM]

That is why i told him to have a pencil and paper with him. I saw K.R. Joye with a drop of a good 1/8" and the strut was almost below the keel and the prop end was angled down 2 or 3 degrees.. he's working with a twisted hull, so small incruments of movement could be monumental on that hull! How are you and Chris Fine getting along!!

[DLM]

go www.rumrunnerracing.com and go to questions where tony t. wants to put Aveox 1514 in a scat cat 26 and shows transom set!!

[TXTRCR]

finally, its finally running well except for a little cavitation when going from a dead stop or spin out. other than that it seems to be running well nice and flat on the straights even through the turns with enough speed and air under the hull to blow over if you drive it full throttle into the wind like i did. the nose of the boat went verticle so i let off the throttle and turned the rudder fully to the right or left i cant remember and with the rudder almost parallel to the transom the nose of the boat set back down as soon as the rudder hit the water, it was awesome. i had a little heat build up so i added water cooling to the motor i put as many coils as i could fit on the can the motor mount and the flux ring/torque ring and motor mount design makes it impossible to cool the can nearest the output shaft so i only got coils around the end of the can about 1/4 of the way down the can. the motor was only slightly warm but the batteries were smokin hot and the speed control was only slightly warmer than the motor it wasnt so hot that i couldnt touch it. in fact it was like i dont know the headlight of a car that had been on lowbeam for about an hour. just slightly warm. but the batteries were like so hot that they could have burst into flames at any minute instantly i took them out of the hull and laid then in the cool grass around the pond edge to cool them. also the battery life was only about 3 mins or so with 12 3300s shouldnt i get more than that.

[DLM]

You didn't say what motor you are using but a full cooling coil and hood cooling should be priority. You say batteries were piping hot, bad sign. Drop down one size to increase run time ( prop ). Make sure the cable is lubed. I think i would run it for 2 minutes at a time to check heat till it is dialed in. Check your alignment from endbell thru prop for a straight line and your coupler to cable is a smoothangled line. When you put cable into coupler, there should be no catchs and slide right in and at drive dog leave a little over 1/16" . The cable will tighten up, so you need room there. Thats what you call progress!! If your going up in pitch, go down 1 size or less mm and vise-versa.

[DLM]

Well , take care of yourself, i cannot help you out anymore and the best of luck! have a good summer~~