Magnumdekes 1976 22' Starcraft Islander

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

Thanks Mark, great reference!!!! Means I am a little light on floatation, close but not quite. Kinda confused on how to figure it, I am going with the floatation foam theory of 60lbs per cubic foot, except no foam just dead air and of course I have to subtract for weight of bracket. Anyone got a more accurate formula, I am not a math genius, LOL. Just trying to break even or slightly under on the bracket and motor as far as buoyancy. Using the 60lbs theory I am around 540lbs of buoyancy, - bracket @ a guestimated 150 lbs, and then a looper 150 @ 370 lbs, would end up at 520 lbs of weight. almost even if I am even close on my theory, kicker motor gonna blow it up into a negative situation! All right, am I close in theory or way off the mark???

?????????? Need a little help here!

 

[TruckDrivingFool]

Re: Magnumdekes 1976 22' Starcraft Islander

First comment on this, but have been following along, so far looking good.

No genius either, we missed the question since your math seems right. So long as your bracket volume is 9 cubic ft. that is.

 

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

First comment on this, but have been following along, so far looking good.

No genius either, we missed the question since your math seems right. So long as your bracket volume is 9 cubic ft. that is.

Thanks, ya right at 9 cu ft, thanks truck!

 

[TruckDrivingFool]

Re: Magnumdekes 1976 22' Starcraft Islander

Alright I've had too much time to think,

If you're just looking at floatation from a swamping aspect I'd think you're way fine since you've added essentially extra floatation in the amount of what you're adding (OB and bracket) without considering the weight you're losing from the original I/O.

If you're looking at it from a perspective of maintaining the original water line I'd think you'd need to take into account the difference in the weight lost and gained. It could make a difference in how much of your added buoyancy is below the waterline.

That make any sense? I know you're following what Weldzilla did and his worked out good, but I thought I'd mention it.

 

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

So when at rest, my floatation pod will not all be submerged, say two thirds will be under? Therefor I would be about even on the out board weight and the pod and swim platform weight would represent part of the original I/o weight? Meaning I would still be ahead on weight savings. Center of gravity will have shifted somewhat rearward, I will be moving battery's and fuel cells forward to the driver and passenger seat locations, Close to even on center of gravity then minus a few hundred pounds of original I/O. When on plane all bets are of as float pod will not be doing much, center of gravity will rotate back toward stern and then the dreaded porposing will be possible??? May need more weight forward to counteract this, have plan for that if needed!

 

[TruckDrivingFool]

Re: Magnumdekes 1976 22' Starcraft Islander

First off I know the I/O conversion comes up more than randomly, so part of my reasoning for posting my thoughts is to point out concerns for the future readers.

I remember reading through Weldzilla's conversion and that he had great results so I still think you're fine.

So when at rest, my floatation pod will not all be submerged, say two thirds will be under? Therefor I would be about even on the out board weight and the pod and swim platform weight would represent part of the original I/o weigh? Meaning I would still be ahead on weight savings.

That was my thought but I don't know what your I/O weighed.

Center of gravity will have shifted somewhat rearward, I will be moving battery's and fuel cells forward to the driver and passenger seat locations, Close to even on center of gravity then minus a few hundred pounds of original I/O.

Yes sound's like you've thought further ahead than I did in my original post.

When on plane all bets are of as float pod will not be doing much, center of gravity will rotate back toward stern and then the dreaded porposing will be possible???

This I don't know as your pod may provide extra leverage and compensate for it.

May need more weight forward to counteract this, have plan for that if needed!

Just remember I'm a trucker not an engineer and I'm more thinking out loud than anything. Hopefully the smarter guys will chime in as now I'm curious as to how far off my thoughts are.

 

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

"Just remember I'm a trucker not an engineer and I'm more thinking out loud than anything. Hopefully the smarter guys will chime in as now I'm curious as to how far off my thoughts are. "

Ya I am trying to have a sounding board here to work out the math in all of our favors, Trying to make the often thought about, seldom done and rarely successful outboard bracket a viable alternative. It is possible if the math is accounted for!! Just a matter of putting the equations in effect and accounting for the variables. I believe Weldzillas boat to be a close representation of mine, and a good starting point. More important to me is coming up with a thought process that make it possible for others!!!!! I also believe that there are situations that make outboards more desirable for some of us no matter original configuration. Let's have a discussion on the process and things that need to be accounted for.

Thanks, Rick

 

[jasoutside]

Re: Magnumdekes 1976 22' Starcraft Islander

K, here's my athinkin...

Our old Starcraft Islander hulls have essentially remained the same through the decades. The only major changes have been topsides
Then, at some point in time Starcraft decided to make the OB on a bracket an option, keeping the hull the same. So, I am kinda thinkin/hoping they did the math for us, eh.

Many boats we see here on iboats going for this sort of mod are venturing into unknowns that could make for major problems. The Islander has been there done that with the bracket. So I think with some quality structure building (stringers, transom, knee braces) you should feel totally confident going this route.

Have fun!

 

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

ya when I get to work tomorrow I am going to scan in a copy of my blue print and material list for posterity, should be a good resource in the future.

 

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

Out board bracket swim platform plan, let me know if this shows upView attachment Swim platform.pdfView attachment Swim platform.pdf

 

[jasoutside]

Re: Magnumdekes 1976 22' Starcraft Islander

Check this out, all ready for action...

http://www.ebay.com/itm/Single-Outb..._Accessories_Gear&hash=item4ab8a1732e&vxp=mtr

 

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

Ya new would be nice, but I am on a creative bottom feeder budget, I have 400$ into scrap scrounging, My buddy with a press brake owes me a favor, but we could call the bends 100$, and grinding wheels and wire at say 100$. I like doing the project with kicker bracket and all for 600$ plus my time (which we all know is a loss on boat)= Sweat equity. Plus no shipping! I am taking it on!

 

[jasoutside]

Re: Magnumdekes 1976 22' Starcraft Islander

Yah, if I had the welding skills for something like that I'd go for it too. But, for $1K, that's not a bad deal anywho

 

[TruckDrivingFool]

Re: Magnumdekes 1976 22' Starcraft Islander

I see it,

I found this

The weights listed below are the engine coupled with the Alpha drive.
3.0L....635 lbs
4.3L....848 lbs
5.0L....946 lbs
5.7L....946 lbs

These are all the motors that use the "LX" designation.

Source(s):

Me. Mercury master technician

So I'd say your already ahead by at least a 100 pounds without even considering your added floatation.

Forgot where I was going with that so maybe it'll come back to me later.

 

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

Yah, if I had the welding skills for something like that I'd go for it too. But, for $1K, that's not a bad deal anywho

1k is a steal compared to some prices I have seen on the name brand brackets, i have seen used ones for that

 

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

I see it,

I found this


So I'd say your already ahead by at least a 100 pounds without even considering your added floatation.

Forgot where I was going with that so maybe it'll come back to me later.

Ya I would be interested to know what you were thinking! I lose track all to often myself!! LOL Should be lighter than is was with the omc in it, might have to compensate for that for the hull to dig like it should cornering??

 

[TruckDrivingFool]

Re: Magnumdekes 1976 22' Starcraft Islander

Think I was going to go into trying to find the effects of cantilevering (no idea how to do that) on the weight of the OB vs. the rest of the boat. Along with moving you CG it might equalize the weight difference. Maybe that's why (as Jas mentioned) Starcraft went ahead and did it.

 

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

Started on the swim platform/outboard bracket. Ended up cutting all pieces instead of bending on a brake, the 1/4" did not like bending so much. So here we go picture bomb!
Here is the platform notched and ready to bend, luckily I tested a piece first

So I started cutting with the plas cutter

Edge assembly

 

[magnumdeke]

Re: Magnumdekes 1976 22' Starcraft Islander

Got most of the perimeter tacked together

Started on the float pod, 13 degrees is necessary

Pretty close to 13, adjusted after tacking it up

Got a side panel cut

Blazed some welds

Starting to look like something, 4 more hours will be close to done!!

 

[mark1961]

Re: Magnumdekes 1976 22' Starcraft Islander

Did somebody say foreign order? .....lucky you.....thats one way to improve your aluminium welding skills, nice work.