Adding extension boxes to SSMIII...INFO PLEASE.
 

Unless you use Stelling's boxes with internal U joints and drive shafts You will have to raise the engines. ( this is true for BRAVO drives - I don't know if Stelling makes boxes for #3 drives

They do have internal drive shafts and u joint's.

general rule is up 1" for every 12" of setback so that would mean you are trying to go up 4". with a 10" setback you are going to try for a 4" offset in that 10" which means the u-joints are not going to last a week.

absolutely...

Well---sh!t ... I guess I will cut the transom and run it with what I have and then try to find some 5's when I have some spare change.

IF you don't cut the holes any bigger or taller than you have to you could always lower the boxes later.
Some people slot the mounting holes on the box ( transom side ) so that if you loosened the bolts the box could be raised or lowered with out removal.

Here ya go...https://www.offshoreonly.com/forums/...s-tie-rod.html


Jon

Yep that is nice set up but the 25K is not gonna happen right now. I am doing a full resto/rebuild to my 36 and the money is already WAY out of hand............opps I guess I will retire at 90. I have an opportunity to buy the boxes and just run what I have but I want to make sure I am going to get some gain out of it or I'm not going to do it.

https://www.offshoreonly.com/forums/...-did-i-do.html

adding the boxes at that height will likely hurt you. you said you were going to cut it and run it so does that mean the transom was replaced? and if so why not raise the engines? or is something not allowing the engines to come up.

yes new transom glassed in but i cant raise the engines anymore without causing exhaust issues and i am not going to buy new headers and or new tailpieces

Here is a link to my thread about my cabin project....that is now an everything project .

https://www.offshoreonly.com/forums/cigarette/344159-cabin-project-what-did-i-do.html

I bought those drives...


I do have a set of 4`s available.. LH is in great shape the RH needed a new set of lower gears, they are at Collabellas right now. One drive has a big shaft, the other is a small shaft (new) . I ran the Arneson adapter on the smaller shaft drive no big deal.
If you wanted 2 big shaft drives I can do that too , about $1500 for the big shaft.(nows the time since they are apart)
I was just going to keep them for spares..

They come with 2" spacers so you got some room to experiment.

$9k as is (19 and 26 splined shafts)
$10, 500 with new 26 spline big shaft.

4`s are same height as 5`s

I`ve found the best set up is about 1-2" below bottom. The best rooster is even with bottom thou :D

With 5s - yes, you should be able to go up or down an inch with the boxes, there are three bolt hole patterns (similar with #3 setup? I dunno). Then you can space down 2". Typically these are setup @ neutral, so you could theoretically go up 1", and down 3" from hull bottom.

I don't think you're going to get what you want with putting the 3s on boxes. Looks like you may be able to achieve <2" up max (factoring in "up".833" w/ 10" box setback, and mount the box on the "highest setting" bolt hole "up" 1" = 1.83")?

So now its 275K.......:7160:

Try to find a pic of a transom cut for IIIs, I know that my transom has very little cutout for the 5s. Basically just enough for the driveshaft to poke thru and some hydraulic lines. I'll look for a pic.

https://cimg8.ibsrv.net/gimg/www.off...d852d7a92.jpeg

III cutouts

So if i change to boxes or 5s later i would have to fill in the transom?

drives
 

or IVs ... I have a guy who has a pristine set, and SSM boxes utilize a bearing carrier/support, you plug your drive into the transom assembly just like if it were mounted to the transom ... I have same set up except my boxes are 15" setback. same applies to a 10" the carrier is mounted off the rear inside of all SSM standoff boxes, deeper the box the deeper the carrier so a longer driveshaft would be needed, you will also need to change your transmissions to driveline transmissions.

X dimention
 

you're making a drastic mistake to run a SSM III that high, it was not designed as a surfacing drive, the best thing to do on that Cig is to run the engines as close together as you can 33" to 35" Center to Center, and let the drives running surface do it's job around 3" below, otherwise you will turn this boat into a POS, the center of gravity/weight distribution will be out to lunch if you jack them up to surface a III drive, and again it's not designed to go that high up...
if surfacing is what you want then a SSM#4 or #5 is what's needed,
why would you want boxes in the first place?

I don't want them up high but right now they are pretty deep from what I remember so I want to get them up a little bit from there. The engines are are on 36" centers and we are not changing any of that. I really don't want surfacing drives just trying to move them up a little bit and get some more leverage for the bow. At this point I just want to make an informed decision so I know what my options are down the road. I don't want to have to re cut and refill the brand new transom I just put in.

Just to let you know the higher you go the less leverage you will have. Can you measure from the bottom up to the center of the top bolt holes on your transom I can give you your X dimension off of that measurement Regards Dan

https://cimg1.ibsrv.net/gimg/www.off...9519409d2b.jpg
https://cimg4.ibsrv.net/gimg/www.off...8b6cf75621.jpg
Not the best pictures but it's the best I have

https://cimg8.ibsrv.net/gimg/www.off...ae5d3a0dcd.jpg



Man that lower of them 3`s is like a mile long. Thats a lot of drag.

they made #3's without the cresent lower ??

First generation number IIIs and number IIs were non cresent I believe it wasn't until about late 70s early 80s that the cresent lower came out. The 35 Cigarette race boat I have at the shop is non cresent its a 76 model and I have a set of drives off of a 41 attack that I believe is an 81 model they are also non's Regards Dan

There is a 5 5/8 of an inch difference between the two drives.

x dimension and drive height are two different things. x dimension is the point from the bottom of the hull to where the upper shaft goes thru in a straight vertical line. drive height is where the propshaft is from the bottom with the propshaft parallel to the bottom. if you have no spacers in the drive, if you tell us the drive height we can look up and see what the x dimension is right now.

Does anyone have a schematic of the these drives mounted on a transom with dimensions? I saw one a while back but I can't seem to find it.


Compedgemarine---- Thanks for the information. I always thought the x dimension was from the bottom of the hull to center line of the prop....glad to be set straight and I never thought of the drive mounting height VS the X dimension. I just thought in my case they are not exclusive as there are no shorter lowers or spacers available as far as I am aware.

Stilll looking for mec drawings on this if anyone has them. I saw them at one point and the gave all of the dimensions of the drives and from different points on the drives but I can't seem to find them now. Any help would be appreciated.