colosus

Hi guys

Im on a new project and need some help.....

I need to know how to go about stretching an abs type hull.... the boat in question is the old Graupner Systems Cat...size is 830mm long and about 270mm wide...build seen here :
http://www.funrcboats.com/BuildSysCatE.htm

This is Semi-scale....and i think its too short...the real boat was longer...so i was thinking of making it 1metre or more, i think the width can stay the same, to me this looks like a stumpy version of the Systems Cat that was made in 1987 i think...although the model does move nice on the water...it could do with being longer...

Mine is still in the box but with no original hardware...and before i put it together, as its in two halfs, i want to try and stretch it...
maybe by cutting the hull at 3/4 mark from transom to nose, ply sheeting layed inside complete length of the hull attached with glue/fiberglass & some kind of rivits or something, then glass the thin gap from outside... ??

I didnt want to make a complete mold, time and money...not worth it ...i think...there must be ways to do this stretch, i just want this old boat to be more real scale.. here is a site with pictures of the real boat...very hard to find :
http://www.offshoreonly.com/forums/c...7-systems.html

I have an alu rudder 115mm kit with flex which i think will work with this boat but this i will deal with when its time..

martno1fan

How about stretching it using balsa and some abs sheet,tidy it up then use the inside as a female mould to make a bigger one using epoxy and cloth.For a one off replica it might work.
If you had accesss to a large enough oven you could also use the outside to then make one in abs ,youd just need to make yourself a vaccum box and connect a vacuum to suck it down over the orriginal one.

colosus

Thanx m8 for a reply....great idea ..cool

I dont think i have the knowledge to get a good hull from a mold..and what length should i do it without touching the width maybe 135 length...wooohooo..how to do the fiber so it goes into every corner without lifting...and wat products to use...

I wouldnt know where to start....ive done fiberglassing before and my Dad knows how to make boats...but he lives in Spain ...lol....i need to know what materials are needed and how to do it..
I dont have a problem creating something or making it longer that should be easy for me....
Using it as a female mold sounds great...good idea....

What do you mean about the balsa...where are you thinking of putting the balsa ?

And the vaccum box.....how will it work..if i was to go that way..is it like putting the boat in a tight box and sucking the air out ...

martno1fan

The balsa will be stiffer than abs so the idea was to keep things rigid for you to take a moulding from the orriginal.In all honesty id forget the whole idea and buy a 1 mtr hull in fibreglass and modify the top to look how you want.
Vaccum box is easy heres one and how to build it,however finding an oven large enough to get a 1 mtr piece of plastic in is the problem lol.
Mart
http://www.youtube.com/watch?v=e5CGfoxnKaQ

colosus

Great video...looks easy enough....

hmm only place i can think of with a large oven is the bakers ...lol ..oh and the place where they make artificial arms & legs, braces and stuff...
maybe place the plastic infront of a great big space heater..then lay it over the hull...wow not sure what idea to use..lol...emm the heat from the plastic ..thats gunner melt the original hull...muahaha

Yea i didnt want to just forget this project i wanted to give it ago....i really want the big HPR cats...but hey...money money money...

Atleast i have the hull, i just need to work with it and create something...
Do you mean using sheets of balsa on the outside of the hull, then fill it in with sheets of abs ? attach the sheets with epoxy ?

colosus

lol its so crazy here at this site...hardly anyone has any idea's...or help with fiber-glassing...68 views in 1 day and only one guy bothered to respond..I cant be the only one playing about creating stuff ??

Once i've cut the Hull where needed, what would you suggest doing to keep the parts straight ? maybe i should glass it on the whole exterior to hold it in place.. ? or balsa rib it then fill in with abs sheet's, or sheet balsa the exterior then abs the gap ? using little filler, sand smooth, then gel coat and she's ready for the fiber..?

Im thinking of a scale version of the SIMAC REPORTER Cat, and it will be like real...with two stingers and two motors, the motors will be something like Leopard 2200kv..there about $75 each......this old Cat will fly when finished..

martno1fan

Hi ok so you want to lengthen the boat and fibrglass the outside ?,easy enough balsa on the inside to lengthen and join the two parts together then you could use abs to fill the gap,then a little filler ,next you need to decide wether your leaving in the abs or removing after.If leaving simply scuff up the outer then use slow epoxy and some thin cloth lay alayer let it fully set,once this sets you can build up the layers using some thicker cloth say 200g cloth maybe 2-3 layers one at a time,use an old credit card to remove exess resin between layers.Reason im saying do it in seperate layers is to keep the heat down during curing so as not to melt the abs.I cannt say it wont melt the abs as ive never tried it,it is a possibility.If alls good when your done you will have some serrious wet sanding to do to get the running surface nice and smooth,another reason to use the credit card to get rid of exess resin before hand.You will also need to seal the balsa inside when done with epoxy resin.
Mart

colosus

Its this that im not sure about

you said use the inside as a female mold....so if i do this...i need to make the outside stronger and kept straight...
Now talking about heat....damn....now i remember when i was fiberglassing bumpers for cars the temperature was so high i couldnt touch it...
Thats gunner warp or melt the abs...lol
Is that the same even for vacuum forming ?
My plan was cut hull, plank the outisde, fill inside with some abs sheet, filler, sand smooth, gel coat, using non hardening plasterscine build the outside of the hull into a rectangle block so the hull doesnt move or flex...then layers of thin fiber and vacuum it without putting it in the oven..like here on youtube..i know this is carbon but maybe do the same with fiber ?

http://www.youtube.com/watch?v=VodfQcrXpxc

colosus

Oh i was thinking about twin Z- Drives for this Cat...i want it close to real as possible...i will modify the top of the boat so you can remove the engine bay covers on both sides..
Exceed have some CNC outdrives on there Viper & Seahorse powerboats...and even Proboat..

But maybe i have to use twin Stingers...what you think ?

martno1fan

I think as its a one off build your best bet is cover it outside with glass,yes heat may or may not be an issue cant help you there to be honest as ive never worked with abs.I supose it depends how thin it is.
I still think your best bet is buying a bigger hull to work with,you can pick up bargains if you search long enough.
Mart

colosus

Thanx m8...thank you for your advice...shame your the only one interested..

I think i will get some abs sheet and do a test with fiberglass and how much heat it creates...to see if it warps or melts abs...

I love this Cougar Style Cat its Vintage 1986...so i dont want to buy just any hull...it has to be the same, because the other Cats transom's are totaly different and i would be crazy to chop up a new type to make a vintage Cat..

Either that or i need to find plans to build the same Cat out of wood, like the max cat v2 or Lithium Cat and now i even have a mystic plan..but a Cougar Cat i cant find...

I want the length as that adds speed and weight plus will look more scale, on a german forum they added 30cells..
As for the drive system, i found the original Hydrospeed set cheap and maybe i will use two of them instead of those expensive outdrives i pictured lost post or modified GTX 650 outboard motors..those will make it look real when i finished modding them to have inboard motors...but cost 70 quid each.

Feel free to add anything to this build please..i need as much help as possible..cheers
I will post pics when i start the build.

martno1fan

You wont be able to use fibreglass as poly resin will eat the plastic,you will need to use epoxy resin m8.I like your determination and wish you luck.
Your idea to build from scratch might be your best option,maybe you could modify one of the plans you have ?.
Mart

Got RPM

I and a couple club members had Systems boats back in the day (when they first came out) and they are weak to begin with. The ABS on some lots was thin and brittle, and after 25 years sitting in a box it has certainly not gotten any thicker or stronger. One nice thing about the Systems is that it handled pretty well - the long narrow "scale" cats do not handle nearly as well. Particularly if you use steerable outdrives (I ripped it off my Systems and never regretted it) the lengthened cat will hook and roll over in a heartbeat. You will not be happy with the result after all the effort and $$ spent.

IME you would be far better off selling the boat as is and either building one from scratch, or buying a more suitable hull to build. There are a lot of good, new, strong fiberglass cat hulls available for not much more than you can get when you sell the Systems. Then you will have a stronger, better looking and better performing boat which you can be proud of. Or you can cobble together a boat almost guaranteed to disappoint. On the other hand I can understand the attraction to doing it all yourself, and if you decide to go that route I wish you good luck and lots of fun.




.

colosus

Thanx guys for the info...

Yea...i've checked these Systems Cats out on youtube...and some people like to turn real sharp with them and make em dart left and right....thats not what i want it to do...this will do something more of a Daytona course...long straights.

But why would you say the lengthened cat will hook and roll..? there were a couple of versions from Cougar and one was a lot longer but using steerable stingers..the older one used type z-drives..

because if you look at the real one it is slightly longer, somewhere in the middle needs to be lengthened on the Graupner model and i suppose they wanted to keep the cost down when making it, they would never have made a 1m version then said no good lets make it shorter..would they ?
making it something of 970-1000mm instead of 830mm, these cats are wide and i would think difficult to roll...but you may know what your talking about if you seen it happen..

for the outdrives, i'm not going to spend loads on this..i will strenthen the transom either with carbon plates or ply and maybe using two original steerable Hydrospeed outdrives...or two stingers with a rudder in the middle...powered by two Leopard 2200kv..!! if i lengthen it then the hull be complete fiberglass or carbon..ouch lol so not the original abs flimsy stuff..

So all that said do you know of a Cat that has the same style base & transom ? top is no problem as that can be easy to mod..i did see one larger Systems Cat the same but i cant find it anywhere..
I'm not out to proove anything, i just really beleive this Cat should have been longer..and more to scale..i will be making it as scale as possible to revive this beast..the old type model has grown on me more than the new Mystic Cat.

Rebel bay

The original drive for the Systems was this hydrospeed model

Rebel bay

You can use an aluminium actual version like this one, no problem. If you want to build a long System buy a used Systems, this is the best choice.

cgi.ebay.fr/Graupner-Systems-Cat-kit-UNBUILT-in-BOX-Parts-/320980928353

cgi.ebay.fr/GRAUPNER-Systems-Rennboot-NEU-NEW-/120982506597

colosus

Thats a Very nice Cat by the way...good colors
I do have the alu stinger rudder pictured in first post...

Rebel Bay i posted some pics again..what ive got and seen on the original is the Hydro-Speed II 1782 that i pictured earlier, its the 26euro steerable outdrive units without the flex, and i have two of them, there not scale but they look good in the water, i know there only teflon and can withstand up to 100kw of power, so i guess they will bust with the Leopard motors, or i will modify two GTX650 outboard motors to run inboard...these will look scale once i finished, and theres nothing in them just motor & flex so no gears...i will remove the top GTX cover and mod the flex so it comes out the transome in a straight line into the GTX650 units.. fitting one each side like the real deal...just not sure if the 650 is big enough..i think it is..the motor will not be ontop !! you can just see very simular drives on the real Cat in my photo here..

On the other note, i can only find two other hulls that are simular to Systems Cat...and they are 48 and 60inch boats (1175mm) and 60'' is 1524mm, the first one is 240 wide same as Graupner Systems so they made it longer...thats Thunder Tiger Desperado Cat
The other is Expresscraft but there systems cat is the very old one...these both cost over $300 not to mention the import frieght..
http://www.expresscraft.com/systems-cat.html
http://www.ruberkon.com/desperado-rc...ess-motor.html

So im still at a loss...trouble is ...once i cut this, there is no going back...i will have to make it work..

tc4 drft

This is awesome. The Systems cat was my very first rc boat in the early to mid 90s, and I still have it (at my dads house anyways.) I have to correct Rebel Bay, as the original drive was acutally a dual motor that was geared, and coupled to a steerable outdive, like pictured above. The Hydrospeed single motor may have been added in later runs of this model. Good luck on this build!! Cant wait to see the finished product!

colosus

yea the Drive unit Rebel Bay has is the same for the Key West Cat..the unit i picture is for both single and duel motor setups, single being the standard and duel speed was the hopup option...
but you can adapt any drive unit for the Systems Cat, im just not sure what to use yet...and the single aluminum rudder just doesnt do anything for me, i need to think about the drive units too before i cut & build the boat, the top round motor hatches will be removable and will open like the real Cat.. i hope..

I may modify two gtx650 outboards, drilling straight through the prop mount to the back, adding tubing and teflon flex, and remove top cover.. like in my mock picture here..it will look like this..

expresscraft

I would just make a new mold, and use your boat as a guide to size up from,ABS is not the easiest thing to work with, nothing really sticks to it. This one is 60" and is made out of carbon fiber,the real cougar boat had some changes over the years,It's kind of cool to know that it will build into a few different boats.here are just a few.

colosus

Thanx Espresscraft..great photos..i really like your models and ive got your webpage bookmarked...only its the very early Systems model and a little off my price limit...yours could be modified to look the same as the "Simac Reporter'' or ''Chevy Systems''Cat but that $350 is for hardware for the cat i already got...ouch

maybe somehow if i use the internal ply ribs and make more of them all full length of the hull and scale them down then i could build a wooden version of this cat to the length i want and then make a mold..lol this will take forever..

Is there any type of liquid that i can pour into the hull, that sets hard enough to make a plug..lol
Or does anyone have the plans to a Cougar cat that i can have to make this one in ply & balsa..?

colosus

ahaaa look i came across these pics on a German site...
Think they were strengthening the hull....but he's used fiberglass....

martno1fan

Hes also used csm with epoxy dont do that epoxy doesnt work well with mat as it wont break down the binder in the mat,use cloths with epoxy.
Mart

Rebel bay

Have a look to HOR news, very nice parts

www.horracing.com/product_info.php

colosus

Cheers guys..

I think thats all that i have ever used (not for boats) on car bumpers and other things, that same tin with about a metre of cloth...

I was thinking..lets say i lengthened this hull.....now i use release agent or wax on the inside of both halfs of the hull....brushed it with resin ...let it dry 15 mins...then layed the whole interior with fine cloth....brush more resin keeping it smooth as pos and let to dry...24h
Would that not give me an almost perfect finish on the outside once i seperated it from the hull...?? i could then build up thicker cloth afterwards for strength.....what you think guys..?

Rebel Bay..thats a nice piece from HOR but i dont like it..its more tunnel F1 boat style with motor on top...it would work..but it will look naff..the motor will sit higher than the round engine covers on the Systems Cat...something like that but with internal motor like the old graupner Z-Drives...they were perfect but were geared so no good there...im still toying with my GTX650 idea..or two stingers and a center rudder..