Bravo or SSM III ?? only options
 

If you're only option was bravo's or ssm III which would you rather have?
I have bravo's on my hawk, and am getting concerned about continuous drive breakage. XR's are not in my budget nor do I want to rebuild them every 150 or so hours.
But I do have my ssmIII's, gimbles, and transmissions still would it be worth hanging on to these or is this old technology not worth it, and won't perform? these are my only 2 options keep the bravo's with hp transom assemblies or swap to the ssm IIIs, so please dont tell me put imco's or bmax's on it unless you want to trade which is more than welcome :lolhit:

Go for the SSM#3s and a high x-dim. Much stronger than a bravo and they run surface props. An interesting thing could be to see if you could in any way swap yor IIIs for Vs. The lower drive x-dim makes for easier and better installation. If you are running biggish power, your bravos are going through hel! on that boat and are on borrowed time anyway.

I have several buddies who have both of your setups on big heavy hulls.

42 Fountain. Stock 525's and XR's. Breaks drives. Yes. STOCK 525s.

42ft Wellcraft Excalibur eagle. 540's, bravos, breaks drives.

46 Black Thunder, XR's, 575's, breaks drives. Why BT would even install this setup is beyond me.

31 Sonic, hopped up merc 575's, modded up bravos with cryo this, cryo that, breaks drives.

386 Sonic, 575 mercs, XR's, good for eatin up vertical shafts several times.

I could go on for a while here. No need to beat a dead horse.

Now, SSM buddies.

41 Apache. 598's, 3A's, No drive breakage.

38 Flatdeck Cig, 800 blower engines, 3A's, no drive breakage.

38 Flatdeck Cig N/A 540's, small shaft III's, no drive breakage.

39 Aronow Cat 650's, Small shaft III's, no drive breakage.

38 Cougar, 572's, small shaft III's, no drive breakage.

38 Fountain (my boat) small shaft iv's, 650's, no drive breakage.

33' Fountain 900's, small shaft iv's, no drive breakage.

You see where i'm going with this bud??? All these boats I listed are used on lake michigan. If you like running big water, with any kind of decent power in a 40' boat, bravo's just wont cut it. Not xr's, xz's, x's, y's, or any of that stuff.

Im sure if you boated on a inland lake with calm water, you may be ok, for a little while with the bravos. If it were me, i'd put the III's on and swing the big props.

Not big power but enough to break bravos! Lol about 590 fwhp each

Thanks m/t looks like next winter will be another rerig! What x would be good? It's at 18 now for the bravos

Honestly if you have all winter to do it and your labor means nothing to you, pick up a set of arnesons like what's in the swap section for $7k, sell your other stuff and be way ahead of the game.

Great idea problem being selling the 3s and gimbles, had pretty much no interest in them at all. I'm sure I could sell the hp gimbles and bravos but that's only about 4k

If you are at 18" with stock length Bravos, an x of 20.7/16" will put you at the same height. I would a least go with 23½"-24". You can always use a 3" spacer and get down to or close to current prop depth if needed, but 23½" will suface your IIIs and that is what they were meant to do. With the big cleavers, you may even be able to go higher. Next question is, do you have room under your hatch?

IMO jamie, use the boat as is this summer to see if its something you want to put alot more time into or sell. Youll prolly figure it out pretty quickly. If you decide you want to build an 85 MPH Hawk, then start collecting spare SSM parts to keep in inventory if you decide to do the re-rig. I know theyre hard to come by and can be expensive, but it should be alot stronger for your power upgrade next year! Haha...That boat may also like the weight of the trannys forward. If those Bravos make it through the summer, theres a chunk of pocket cash when u sell them. Plus OP should have a ton of props for #3's. This boat has been altered hundreds of times! Hahaha

Or sell the iiis, and the bravos, and put some iv or v"s on it and keep the engines mounted low. Then bolt some blowers on for a 90mph hawk with a rooster tail :)

Ideally I'd love to get rid of the 3s and put 5s on it but can't find a buyer for the 3s, it's not so much that Im trying to gain speed just reliability. I don't want to be rebuilding drives all the time. These baby blower motors combined with the weight of the boat is enough to destroy bravos and figured since the 3s are sitting here in my way I'll put them to use next year

Plenty of room, has big blower scoops on the hatch

to be honest i wish i had a hull to throw those on that was already set-up for arnesons

What do you want for the III's? They'll sell.....you just have to lower your price waaaay below what they're worth.....seems like that's the only way to sell something these days. It sucks.

Had them in swap shop drives and gimbles with trans for $8500 obo

X dimension
 

How to measure an x dimension?

Measure perpendicular from the crank shaft or even more precise, input shaft centeline to the bottom of the boat. Keel or pad if it's a single and just the bottm if a twin. When I measure x, I use a straight edge on the bottom and then measure from the point where the input shaft centerline exits the transom. You don't want to get your transom angle involved. If you have boxes, you'll need to measure from the box and not the transom. Due to the transom angle on some boats, boxes will change the x, since the transom angle is not always the same as the box angle. Ie. a straight IMCO box with a 13* angle on a 15* transom will lower the x slightly and vice versa.

Just did a little drawing viewed from the side of a boat, it very rough, but gives a pretty good idea about how to measure. The red thing is a straight edge and the blue line, will it goes without saying. The circeled spots is where to measure.

Don't ever hire me as a graphic designer:D

looks like were going to see how this season goes, try to sell the bravo parts at the end of the year, rig it for the 3's and use the bravo money to replace the 174 blowers with 250's

x-dim on twins. is it to lowest point of keel? or bottom directly below drive. note, the swivel up-down where trim indicators go is center of crank-upper driveshaft for measuring purposes.

Those boxes are setup for a verticle mount, that puts the motors way too high in a standard v hull. Also they are 1:1 ratio - that won't work either and the ratios are not easily changed.

I'd prefer the threes over bravos any day. As a quick guess, mount them with the prop shaft 3.5 to 4 inches below the hull.

I agree. If i remember right this particular hawk 40 has the notched transom??? You may be able to go a bit higher, but the problem with a III is if you go to high, you cant space it down. IF you were doing iv's, or v's, and you were a tad high, you can space it down a inch or two. So, i'd stay around 3.5-4" below like KVogt said.

For reference, my buddies 38 Cig flatdeck drives are 4" below, ssm IIIA, no boxes, no transom notch. Planes off just fine, no slip whatsover.

My 38 Fountain, with transom notch, ssm iv, propshafts 1.5" below the bottom, is very prop sensitive. With the right props, it lays right over. With the wrong props, grab a snickers before you attempt to get on plane, cuz it'l be a while.

Lol, the 3's are a lot different from a 3a aren't they? And yes my boat has a notch

Internally they are different, gears and such. But externally from a dimension standpoint, they are the same.

Oh ok, I thought the 3a had a lower like a 5

IIIA's have the same size gearing as the V's do, also they are big shaft in the latest design, the first design still implimented a small shaft, and that was soon changed out... I just happen to have a set if you're interested... lol

Sure my 3s and a case of beer? Lol

Directly below.

Why on earth whould you mount them so the prop sits lower than the current B1 setup? That will not take the full advantage of the drive, slow the boat down cosiderably and so on. You can get 3", 2", 1" and other spacers for the IIIs. They are surface drives and are supposed to be run as such, so are the cleaver props that go with it now a days. Don't forget that prop technology has come a long way since the IIIs came on the market. I would not go below 24.25 personally and then space from there, IF EVEN NEEDED! 5 blades, 6 blades, 20-21* rake ect. Lots of options available in terms of props. If you want to go fast. go high.

Just to clarify, x is not measured to the notch, but to the bottom.

I believe KVOGT's recommendation was based on the assumption that this is going to be a pleasure boat. Not a Cat, Fountain, stepped, or padded boat. Its a big heavy old V.

KVOGT isn't talking from his a$$. He has a 107mph 38 Flatdeck with Arnesons that he built, his brother has a 38 Flatdeck with SSM V's and boxes, that he rigged from TRS, his good friend Tom had a 39 Chris Craft Stinger (same hull as the Excalibur Hawk) that had SSM IV's on boxes, which i believe ran into the 90's. Not too mention a 41 Apache they are re-rigging.

I can tell you my buddies 38 Flatdeck Cig, with IIIA's mounted 4" below the bottom, while does plane well, has a slip of over 22%, with 4 blade 17" diameter props. Maybe some 10k dollar Herrings would help lower that, but 10k dollar props ain't in the budget. And not sure if they are in LIL Red's budget either.

With 600-700HP per side, in that Excalibur Hawk, Mounting the drives even with the running surface is probably gonna = a poorly planing boat, ineffecient cruising, and the engines mounted very high. He'll need those blower scoops, even without a blower. My old excalibur hawk had TRS, and the drives were in the basement. Standard 3" flame arrestors barely cleared the stock hatch. If I remember correctly, the factory TRS propshafts on mine were like 7" below the bottom!! Running 4 blade hydromotive props on that setup I had about 15% prop slip.

Going up in X dimension doesn't always mean going faster. My buddy Bob has a 2006 42 Fountain, stock 525's, and XR drives. Boat was never that great at planing off, even with 5 blade P5X props. Added 2" spacers, actually gained a couple mph, planed better, and cruised better. Same exact deal with my friend Mark's 38 Flatdeck cig with Konrad's. He ended up running spacers because the boat just ran better with them, and thats with 5 blades too.

My overall opinion is install the III's, keep the propshafts about 3.5-4" below, run a basic 4 blade SSM prop that wont cost more than the drives themselves, nor will they tear them up like a 6 blade running at the surface (III's do have their HP limits). Enjoy a boat that will plane off with a full tank of fuel and a boat load of hot chicks. Also, enjoy a boat that won't blow the props out in heavy seas. Getting on plane with III's mounted at the running surface in 5ft swells will be real fun. I can tell you my 38 Straight bottom Fountain with the shafts 1.5" below, even with the right props, has a tough time getting on plane in heavy seas. However, when up and running, my prop slip is only 10%. Fountain factory rigged mine, but its a totally different animal than yours. Smaller, lighter, pad bottom, etc. If going fast is the ultimate goal, get a different hull.

If you wanna bring the drives way up, sell the III"s, get a IV or V. That was a drive that was INTENDED to be a surface drive. Look at the SKEG on a III, then look at the Skeg on a IV or V. There was a reason the skeg is so large on the IV and V. The III wasnt introduced as a surface drive. The entire reason mercruiser introduced the SSM IV, was in answer to Howard Arneson's drives in the 80's, since the Arneson equipped boats were doing so well and beating the SSM III equipped boats.

For a non-step boat, having the prop a bit low gives the drive(s) leverage to carry the nose which lowers total drag more than the added drag of the lower mounted drive(s). So you could end up with better planing, midrange and top speed.

agreed... a small sacrifice to make in the larger picture of driveability... and yes Mild Thunder, the III, as it was intended by Mercury, was to be run below bottom, not above like a IV or V...
the way I rig these boats is usually in the area of 2.5" to 3" below if the engine location will allow for the high mounting... seems to give the best of all performance, planing ability good midrange and topend performance...

Is there a prop adaptor to run large shaft props on a small shaft? What others props will work on a small shaft 3?

Yes adapters are avial, usually go for around $400 a pair, they make it so a #6 prop will go on a small shaft III

I can see that putting me back in the same spot beating the snot outta the drives!! Lol

Thanks, what is each drive rated for II, III, IIIa, IV, and V?

Sorry for the hijack.

All good, I was curious about that also

Officially, IIIa's and V's were "rated" for 750 hp, but that was probably the original gear spec. I think the net forged polygon shaft models might have had a higher rating. Most people find them completely reliable at 1000 hp.

III's and IV's are rock solid up to 600 something. People push them much harder, and they last a while, but I have seen gears start to go after extended usage at 850 hp on a SSMIII.

Yes, we make them.