Starcraft Chieftain 1972 MK4

[Sc25175]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

The $12K is for bracket and motor. $1K bracket - $11K motor.

I realize there would be some engineering involved but the 25 footer has a much more substantial internal framework that could be modified. Nowhere near any sort of decision but right now I have a cracked block and a very old drivetrain.

I am going to call one of the bracket makers and see what there take is.

One question, I currently have the 165 inline and am not looking for a super fast boat, what would be the minimum HP outboard that would give acceptable performance. I know the answer is it depends ;-)

 

[jasoutside]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

It depends....

 

[jasoutside]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

Kidding man, just being a punk!:heh:

I think you'd need a 150 to be reasonable with that big girl eh.

Oh hey, it may be worth your time to scan through the first few pages of my Islander thread. The OB vs. IO vs. OB on a bracket thing was something I wrestled with.

In the end I really feel like I made the right choice.

Well, plus I didn't have $12K sitting around either:hopelessness:

 

[Stevens520]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

With the old Merc 888 (188 hp) my tub tops out around 30 mph, but I haven't messed around with different prop pitches. As far as re engineering the cabin goes, I think most of the parts could be reused, just placed differently with the exception of some 6" channel to raise the cabin. Some gutting of the benches in the dinette area would be in order to relocate the helm. just toyed with the idea so far, but haven't taken any actual measurements yet. I did find this place with all sorts of project boats, with a bit of hunting, you may be able to turn up an engine/drive.Search to Bid or Buy Salvage Vehicle from Insurance Auctions in USA & Canada Have even seen a few hurricane sandy damaged boats turning up around me on c-list.

 

[Sc25175]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

So your saying you currently have an outboard on your MKIV today or is it a different boat?

The more I look at the subfloor structure I really believe I could tie it into the transom and it would be plenty strong. I am going to the Minneapolis boat show on Friday to look at how the bigger aluminum boat transoms are built. There may even be a outboard bracket vendor I could talk to. Will let you all know what I find out.

 

[Stevens520]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

oops, should have said Mercruiser 888 (Ford 302 block with 351W heads) Man I'm jealous, haven't been to a boat show in years, had that perk growing up since my Dad was a boat salesman; miss getting to explore all the boats. Was trying to head up to Cedar Point for the last one, but my work schedule got in the way.:blue:
Was mulling over re-powering myself, one of the things that I am interested in checking out is one of these:
http://www.mercurymarine.com/engines/jets/optimax-sport-jet/
It's looks to be smaller than a comparable horsepower sterndrive, and no more worries of dinged up props. No brackets to mount and mess with either.

 

[Sc25175]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

Just finished reading Weldzillas thread on going from I/o to ob. I may be sold.

1. Does anyone know if he did more than replace the transom and bolt on the bracket, wasn't clear in reading the thread.
2. I have two buddies that can weld aluminum so I can easily modify the superstructure of the boat but will most likely purchase the bracket from some outfit like Armstrong.
3. Where is a good place to shop for a belly tank?

When I look at the cockpit without an engine and an already huge cabin this could end up being one nice/lightweight cruiser!

 

[jasoutside]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

Just finished reading Weldzillas thread on going from I/o to ob. I may be sold.

1. Does anyone know if he did more than replace the transom and bolt on the bracket, wasn't clear in reading the thread.
2. I have two buddies that can weld aluminum so I can easily modify the superstructure of the boat but will most likely purchase the bracket from some outfit like Armstrong.
3. Where is a good place to shop for a belly tank?

When I look at the cockpit without an engine and an already huge cabin this could end up being one nice/lightweight cruiser!

The ob on the bracket setup is the cat's jammies! So long as you have the bankroll backing, go for it!:thumb:

#1 I don't know/remember, but, if it were me I'd be thinking about tying in the transom to the hull via "knee braces" of sorts. That would be a fairly easy fab job to work through.

#2 Having buds who can weld alum is awesome!

#3 Belly tank? Craigslist, I see them show up for in the 50 bux range pretty regular. Or, grab one off iboats for 350ish.

Having all that open space, no doghouse, no splashwell, would totally rock:rockon:

 

[Sc25175]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

Just got off the phone with Armstrong Nautical and they stated they have done many boats in the 25 foot range and as long as the transom is in good shape and tied into the stringers they have seen no problems. I know I was speaking with the sales guy but after seeing what weldzillas rig looked like I feel confident this can be done safely. I will do some thinking on how to tie in the stringers and then post some pics for review.

 

[Stevens520]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

The 25' Cheif with a couple of 115's hanging off the back of it would be sweet!! Definitely would make docking a bit easier in a cross wind. Forgot about weldzilla's thread on the conversion. I was thinking about going that route, but the admiral pretty much shot the idea down immediately upon hearing it. Gaining the extra cockpit room without reconstructing the cabin is a plus too.

 

[jasoutside]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

Hey, opportunity!?

18' Boat/Trailer - Inboard - Mercury & Trans.

Quick!


(if yur still considering IO)

 

[Sc25175]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

Thanks Jas but I think I am quickly convincing myself that an outboard on a bracket is how I want to go. Much like Weldzilla this is most likely my last boat and when I fully retire I want to go traveling in the boat to distant cruising grounds. On the bucket list is the inside passage from Seattle to Alaska and the Great Circle Route. I have a buddy who is good with aluminum and can build a bracket with swim platform for under $750 and I am looking at late model used OBs for around $7K. If I go this route i figure I will have $15K into the project but will have a solid platform to cruise in.

On another note I am doing the final demo of the cabin and found that the aluminum substructure of the berths is rivited through the hull. Before I start drilling through the hull I thought I would ask if there is anything I should be careful about?

I also want thank you for how meticulously you have documented your build out. It was after reading your thread that I decided to buy an old Starcraft and do the complete rebuild.

 

[Sc25175]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

If I go with OB on Bracket what would be the minimum size motor?

Been reading a lot about Evinrude ETEC and they say their 130hp is equivalent to everybody else's 150.

 

[jasoutside]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

Thanks Jas but I think I am quickly convincing myself that an outboard on a bracket is how I want to go. Much like Weldzilla this is most likely my last boat and when I fully retire I want to go traveling in the boat to distant cruising grounds. On the bucket list is the inside passage from Seattle to Alaska and the Great Circle Route. I have a buddy who is good with aluminum and can build a bracket with swim platform for under $750 and I am looking at late model used OBs for around $7K. If I go this route i figure I will have $15K into the project but will have a solid platform to cruise in.

On another note I am doing the final demo of the cabin and found that the aluminum substructure of the berths is rivited through the hull. Before I start drilling through the hull I thought I would ask if there is anything I should be careful about?

I also want thank you for how meticulously you have documented your build out. It was after reading your thread that I decided to buy an old Starcraft and do the complete rebuild.

Yah man, given the waters you plan on floating and that you are aok with spending a pile of cash, OB on the bracket (better yet 2 of em) sounds like a great route.

On your rivets, can you shoot up a photo of what you are planning to drill out? I think I might avoid drilling out certain rivets - others, no biggie.

I've really enjoyed my project so far. I post up all the detail I can for several reasons. I really hope others can benefit from the smart stuff and the dumb stuff I do, I put it all out there for you guys to see! I also like to talk through the issues, helps clarify tougher jobs ya know. And the biggie, getting the other guys involved is great. They are a huge help and excellent at bumping us along, keeping us motivated:thumb:

If I go with OB on Bracket what would be the minimum size motor?

Been reading a lot about Evinrude ETEC and they say their 130hp is equivalent to everybody else's 150.

Although the Etec is totally awesome, that's good marketing ^^^^ for the most part.

I'd be thinking 150hp (or bigger) with a solid 15hp kicker.

 

[Stevens520]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

I know which rivets he's referring to; they are the big solid aircraft rivets that provoke long conversations on what to replace them with.:fencing: With an outboard, I would probably look for something 150 or bigger, leaning toward something bigger.

 

[Sc25175]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

The picture is of the front berth substructure, for the most part it is riveted to the plywood floor but the picture shows some through hull solid rivets that would need to be drilled out to get the aluminum out so I can get to the plywood. I am going to remove this piece but was wondering if it is any more complicated than drilling them out. Follow on question is how to replace solid rivets.

Another question on rivets, now that I have all the plywood out I have a ton of rivet poop sticking up that needs to be trimmed off and punched out. Is there an efficient way to do this task?

The motor discussion I find interesting. I guess I am trying to figure out how a 30+ year old inline 6 can compete with a relatively new outboard. I will figure this out but so far here are my calculations. The existing motor and outdrive weigh about 662 pounds( found this in starcraft brochure) new motor would weigh about 418 lbs and the bracket will weigh roughly 105 for a new grand total of 523 lbs. so I am actually making the boat lighter. Putting the OB further back seems to make everything better. Planning at a lower speed, higher top end speed and better fuel mileage. I want the most efficient setup that allows a top end between 30 and 40 MPH and if it is only 35 I'm good with that.

Clearly I have a lot to learn!

 

[jasoutside]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

wondering if it is any more complicated than drilling them out.

Nope, not really.

Follow on question is how to replace solid rivets

You could go with regular pop rivets and dab some 5200/JB Weld into the center, or, you could run closed end blind rivets too.

Is there an efficient way to do this task?

Nah, just grunt work. Drill em out or cut em off with a grinder cutting wheel.

I will figure this out but so far here are my calculations.

Yah, your calculations are in the ballpark (which is about as good as it gets really). Having the IO pushed up further in the hull helps with weight distribution rather than having everything at the extreme stern. Also, when you are talking fuel mileage, OB's are way more thirsty than IO's.

But, both of those issues kinda come out in the wash when we are talking the weight reduction and the super technology of the Etec ya know.

Like I mentioned, if you are liking the OB, and have the cheddar to finance the job, go for it:becky:

 

[Stevens520]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

The best video I have found so far on replacing solid rivets
Installing Aircraft Solid Rivets - YouTube

 

[spegtoast]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

Great video. Also cleared up the buck and rebuck question I had awhile back.

Remember... "Tickle your Trigger" lol. I laughed out loud when I heard that in the vid!

 

[dozerII]

Re: Chieftain 1972 MK4

Re: Chieftain 1972 MK4

Hey just read through your thread, I'm kinda thinking along Jasons line. Your talking $7500 for a used O/B plus the bracket and transom re-egineering. I found at least three suppliers that have brand new Mercruiser 4.3 pully to prop with warranty for $8000. way more economical than to run than an O/B. and no need for redisign other than the mounts, Just my 2Cents.