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kap328 11-20-2010 05:27 PM


Originally Posted by KYElimEagle (Post 3257468)
kap do you think if you had a twin cat and you ran a higher x dimension where you could get the SCX lower bullet out of the water it would perform efficiently? I would think that then you would have to use the 6 props to keep from breaking them. I think Nordic did one of their big cats with this set up. Haven't heard how it performed.

Hey KYElimEagle:

That is DAMN good question. You know I have a SCX with a 2 inch prop shaft right now in my garage.

Your question is intriguing and makes me think it might work. If you have a high X you could get the SCX to surface the prop and make it work.

I ran it with no spacer and a 16 inch diameter 5 blade cleaver up as high as I could go without having the cleaver hit the cav plate. On my boat it needed to go up about half to almost three quarters of an inch more than I had. Now you also need to have enough skeg in the water so as not to lose control or have it crab/skate.

It is sooo much tougher in a single engine combo as you have a ton of variables. On twins as you suggest it would be much easier but it will take time and effort. Thus, as I said previously if you have twins use an Arneson. Arneson has a Bravo conversion kit wherein you could use Bravo props. I cannot endorse it as I do not know enough about it to comment one way or the other.

It would be more appropriate for you to talk with an existing owner of a Arneson conversion running Bravo's than having me speculate. It would be even better to go for a ride in a similarly set-up boat that usually either seals the deal or makes you want to run.

Second, the SCX lower also needs to have a more tapered threaded sleeve to lead up to the narrow number 6 prop hub. This will allow cleaner water to the prop versus...what is happening now it kinda has some dirty water hitting the center portion of the prop. It would be easy to make a set out of aluminum.

Interesting idea though I like that thinking outside the box. One other caveat for me is the SCX does have a lot of parasitic drag associated with those bigger gear set's. Couple that with cleavers biting so much harder it might just be a pipe dream for top speed purposes.

It only takes time, effort and lotsa money:drink:.

KAP

campionchase910 11-20-2010 06:57 PM


Originally Posted by kap328 (Post 3257400)
Hello Campionchase910:

Well Mr. Gadgets started off in the right direction but you did not give us enough information on what your trying to do.

1. Is this a Bravo set-up boat...I assume it is but want to make sure.

2. It is single engine right.

3. V-Bottom or Cat.

You can run a SCX/SC drive on your boat they have a complete assembly in the classified section of this site. The SCX can handle your HP/Torque specs. easily.

I know as I have personal experience with this set-up and your type of ratings on the engine side of the equation. The SCX/SC combo is the best set-up versus a SCX/SCX combination. Why! well the full SCX drive scrubs waaaay to much speed on the top end.

Now the down side to the SCX/SC combo is that the weak link will be your lower i.e...the SC unit namely the gear sets. If you fly the boat or jack rabbit your starts your lower will not live. If you get past 4.5K RPM and roll into it... the drive will give you the speed your looking for and be reliable.

No one touched on this but the beauty also with this combination is your not bound by cleaver props. The cleavers in a single engine application will kill you in terms of cost. Why! because you need to find the right one to work on you boat and that is not easy or cheap. The SCX will allow you to run Bravo style props and they are far cheaper and more plentiful than cleaver props.

If you are already budget concious than the SCX is the way to go IMO in a single engine boat. Now if you change one fact i.e...your boat is a twin than I would save your duckets for a set of Arnesons.

KAP
P.S. If you do choose the surface drive send me a P.M. I have three single engine cleavers for sale. I have run both a surface drive and a Bravo and I am currently using a SCX/SC combo by choice not due to cost.

Kap328, thanks for the reply. It is a volvo dpx-r set up and want to change as the moter will be replaced. I have been talking to the gentleman who has the 2 A7's on e-bay on a boat and trying to work a deal out, what do you think my best option is. Sorry it is a single engine v-bottom, appreciate the help. Thanks 4bus also!!

later 11-21-2010 08:01 AM

just curious but are the Arenson a rgt and left hand rotation?

later

575cat 11-21-2010 09:17 AM

How big of a prop can u swing with an scx shorty lower w a #6 shaft , now I have a 2inch short sportmasters and my shaft height is just about an inch above the bottom .

4bus 11-21-2010 09:20 AM


Originally Posted by later (Post 3257802)
just curious but are the Arenson a rgt and left hand rotation?

later

No, rotation is determined by the engine on the standard versions.

Not sure on the Bravo conversions

Mr Gadgets 11-21-2010 10:55 AM

Distance from the bottom of the cavitation plate to the center of the propshaft is 8 1/8". Best I could tell in the dark with a flashlight. If you need more, there is a raised flat spot on the bottom of the cavitation plate that could be cut down some, if needed, maybe gain another 1/8-1/4".
Hope that helps.
Dick

kap328 11-21-2010 11:07 AM


Originally Posted by 575cat (Post 3257858)
How big of a prop can u swing with an scx shorty lower w a #6 shaft , now I have a 2inch short sportmasters and my shaft height is just about an inch above the bottom .


Comment:


It depends on if you space it or not. I did not space it at all SCX to SCX -2 you can run a 16 inch cleaver with about a quarter inch clearance from the cav plate.

That is it... you need a minimum of a quarter of an inch as the cleaver will flex some under load and you do not want it to hit the cav plate under any circumstance.

I needed to go up another 5/8's of an inch to really get it to surface properly. Given the X dimension on the transom I was unable to go up any further.

KAP

575cat 11-21-2010 12:48 PM

is a cavitation plate really needed on such a high drive height and x dimension, in the future I plan on doing scx uppers and probably lowers but the next weekest link woud be the props !

Rik 11-21-2010 03:14 PM


Originally Posted by 4bus (Post 3257861)
No, rotation is determined by the engine on the standard versions.

Not sure on the Bravo conversions

Standard rotation motors. The out drives handle the propeller (RH or LH ) rotations.

campionchase910 11-21-2010 04:14 PM

Rik, I have a lead on two arneson 6's. I only need one. If I sell the other what is iinvolved to have the left hand rotation made to right? One is right and one is left; I am not familiar enough to know what is involved. Also how hard would it be to take my volvo transom rigging out to convert. Is there fibreglass and re-enforcing involved? Thanks in advance.


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