02f350psd

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For my next boat project i am interested in doing a boat with twins (sikks) and i am looking for scale looks with good performance. Just want something that will turn heads but not for racing. Would like to be in the 50-60mph range if possible. What would i be looking pricewise for something like this. Thanks

FROGMAN524

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If you are talking about price range on the hulls, check out www.expresscraft.com , they have a ton of large scale looking cat hulls as well as www.swissmodelpowerboat.de I believe is the website. www.mhzusa.com has epoxy laid up hulls which cost a lot more but you're looking at the $350.00 for a twin size cat from expresscraft. I own their GTX 65" and it is very good quality, not like MHZ, but hey, you get what you pay for. Ken.

Justaddwata

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What was your last boat project and how much experience do you have with boat building. Building a twin setup is a lit more a challenge than it may look.

AS far as hulls. Every manufacturer has a decent cat and many will hold two motors. The Swissmodelboatteam that Frog has listed is good for info but sadly they DO NOT SELL TO THE US as they have had too much effort copied by splashers.

I would consider the Blackhawkhobbies cat which is 74" long and looks remarkably like my PIP cat. The Blackhawk cat is in the $500 range. It still may be tricky nestling 2 motors inside and you may have real trouble fitting them into the sponsons.


The trick will be in fitting your motors into the sponsons of any cat in the 60" range.

Do you have a size and particular style in mind ??

I love Cats !!!

02f350psd

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My first boat was the Super G that i am selling right now. That included buying it rtr but when i actually did get it in the water found many problems and things that didn't work on the boat. Therefore i spent the winter taring it down and fixing everything from the clutch, to servo locations, to the carb, to sending the hull out to be repaired and painted, to polishing the hardware, to rerouting water lines and moving the gas tank forward a bit to adjust the weight onboard. I expect the twins to be a challange as well as doing a cat as i have no experience with one. I am fairly mechanically inclined and up for a challenge. The style i like is one just like mhz's drambuie on ice or something very simiar. I want to stay in this size range as well. I like the scale looks and do want decent performance. Thanks for the help as i would like to start as soon as i can.

Justaddwata

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Do you have a budget in mind ??? I can give you plenty of ideas but the $$ will really guide the project. MHZ hulls are expensive. The quality is good. The service is challenging and experience lacking. Ask them about a twin setup is just wasting your time. I would be looking toward a maker like Expresscraft or Aeromarine who both have experience with twins.

Can I ask why a cat and why a twin ?? A twin is very difficult to tune and have running true. Having two motors running the same direction will make it VERY difficult to drive straight (prop torque). Setting up counter rotating motors will be even more difficult.

I am not questioning your mechanical skills. But having 30+ boats and having built many complex builds I can honestly say that there is a high risk that you will not end up finishing the project. Setting up twins is often breaking new ground. Installing motors, setting COG's, drives, pipes, tuning and tuning (and more tuning). I strongly recommend a single motor / prop configuration. You will likely have a faster boat running a single Sikk motor in a 30" cat than two motors in a 50+ in cat.

Let us know your budget and how set you are in the idea of a twin. It only looks cool when the hatch is off. True it sounds cool with two motors but if they are not both running the same tune then you are not appreciating their performance.

02f350psd

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Would like to be in the 2000-2500 range if possible. I want to do a cat cuz well, i've done (somewhat) a deep vee and the cats i've seen lately look awesome. I want to do twins for the performance and i like the larger cats so i figured i would need the twins for that performance. I did plan to do counter-rotating engines with the twins. I would like to be able to complete a custom build and like the challenge but $$ is also a very important factor (graduating college student). I realize the MHZ hulls are expensive but i like the style and the realistic look of the boat and especially the hatch. Thanks for the imput and would love to hear any more.

P.S. you are missing out on the boating this winter, all be it the water is cold, its just that... water and not ice!!!

FROGMAN524

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02f350psd, I would suggest one large engine such as a QD 70cc inline twin because it has about 14.5hp, has the revs, and can run through a gear box to twin props or to a single. I would stay away from the twins because not only do you need to coordinate the throttle servos, but if one engine goes out or doesn't run correctly, you can't run the boat at all, with the force coming from one of the sides. Just my .02 cents. ken.

Justaddwata

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Kens suggestion of a QD70 would blow your budget from the getgo ($2300 for motor) and be more power than a XX Large cat could handle. I would recommend at least seeing a QD70 in action before recommending one .

The recommendation of a single motor however is a good one. The 73" cat I have pictured above has a single QD35 and will hit 50mph down the straight. [link=http://groups.msn.com/JustaddwatasRCBoats/73inchpipcatdewaltcat.msnw]theres a bunch more pictures of it here !![/link]. The hull from Blackhawkhobbies is $550 (+ shipping), QD35 is $1200 with pipe and mounts. That leaves you plenty of $$ to finish the project.

Heres two videos of my 73 running. [link=http://video.google.com/videoplay?docid=-8398812597129219949&q=justaddwata]The first clip she is not getting on pipe. [/link] [link=http://video.google.com/videoplay?docid=-180794669437820469&q=justaddwata]The second clip is with a better prop and you can hear the motor getting healthy revs and speeds.[/link]

Running dual props from a single (large) motor I would recommend only for very experienced builders. Gearbox installation, alignment, hardware, and configuation is very involved !!

Dual motors I would also clasify as for experienced builders. Additionally when you consider the $300 for each motor, $100+ for each pipe, Mounts, setting up dual throttle linkages, dual drive setups, struts, props, Counter rotating the motor etc. You are looking at around $700 per motor for a dual setup (counter rotated). You have considerations like having to use a reverse twist flex cable (probably an oversight to you at this point). There is just a lot going on with duals and the leasons you learn the hardway may prove expensive.

The MHZ jolly motor cat from MHZ is 69" long and would handle a QD35 well. If your still wanting twin Sikks then they could be reasonably well accomodated.

My advice. Find a hull you like and then see how much room you are going to have for motors and drives. Remember - scratch building a boat is a whole lot more intimidating than modifying a RTR model. Drilling holes in a brand new hull for drive cables, mounting motors, fitting pipes, setting up a radio box. Theres a lot to learn !!!

azimutguy

when building a twin cat, the engines don't have to be side by side unless of course you have the room. as in manny real offshore race boats with multi engine layouts you can install the engines front to back staggering them just enough to allow a jack shaft from the forward engine to clear the aft engine. this layout will allow for twins to be installed in almost every situation. anyway just thought you might be able to use some tips for your next project. beautiful boat by the way

02f350psd

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Thank you everyone for the help, it has been great! Ken, i am going to say as much as i would like to have the inline twin 70cc QD, its out of my price range. I am starting to lean towards maybe doing a more powerful single engine. (Still want VERY scale looks and good performance) I still want to keep the option of twins open so i have a few more questions. As far as the twins, i had planned to do one large scale throttle servo and custom fab some throttle linkage (senior year at school for engineering so i should be able to come up with something) but my question was, do i need to run tachs to moniter the engines to synchronize them? While surfing MHZ's website, i did see the reverse spun prop shaft. (came out with a price tag of just over 1500 for the parts which was everything except the engines(and pipes) and radio and a few other oversights) so i think that is something that would be over my budget. I expect there to be ALOT more than my mods to my current boat and that is what i want. I want to do it all on my own as i am jealous of what i see from some of the other amazing boats on here. Anyone have any suggestions for a VERY scale looking large cat? Thanks again everyone!!!

FROGMAN524

My Feedback: (5)

02f350psd, I got to hand it to you for your ambition. Maybe somebody else can point you in the right direction on this, I have seen somewhere I don't remember, an electronic engine synchronization deal that makes both of the engines run at the same rpm all the time. Ken.

02f350psd

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Well decided not to do twins, decided to go with a single engine in the expresscraft t-bolt hull. Anyone have suggestions for the radio? AM or FM? Thanks

Justaddwata

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FM - Good
PCM - Great !!!
DSM - becoming great

What ever you go with - make sure you have a failsafe installed and set !!

elvir

hello i came across you thread and found out that you say it is diffuclt to tune twins, i differ with you , i have a capracorn 65in. with twin hansons . and it runs perfict. in croatia i am running 98 octane and the motore are set once and the boat runs true with the same direction props.see at http://www.youtube.com/watch?v=2CYN0xIJTYA