2159 outboard conversion

[TheTugistheDrug]

I have a 622 that came with a bracket. Probably designed for a lighter 2 stroke, but I got a F225 on it. The first year I had it, it would porpoise on flat calm water. Not all the time, mind you, but when it did it was irritating AF!
I trimmed the motor, which helped a bit, played with the trim tabs, helped a bit more, but to keep the ride smooth, it felt like I was in the water too deep. I'm sure it affected my fuel economy and definitely brought my top speed down.
I have been considering a different style pod and had a guy look at it for me. The first thing he noticed was that my motor was too low. It followed the hull as done on traditional set ups, but with the bracket on a step and having an angle to it, the leg was in too much water.
I raised my motor almost 2 inches and gotta say, what a difference! Has not porpoised since, top speed has increased and it handles a lot better. One big difference is docking. Previously when reversing, the prop didn't bite unless I significantly increased the revs. Now, if I were to apply the same amount of throttle in reverse while docking, everything lurches forward.
I don't understand the physics and geometry that goes into this sort of thing, but it sure is obvious that there are a lot of parts that can affect the end result.

 

[NDT]

all great advice here, I plan on lifting my engine 2.5" up from the bottom of the boat as my bracket will be 30" back. It's a starting point and I will have to run it and see where the runs when on plane. I realize I may have to move up or down +-1" possibly.

I did consider running an optimax or hpdi 2 stroke for wieght savings. I will be running a high thrust kicker for trolling, so only cruising with the main. That said, it's hard not to want a nice quiet four stroke Imo

I also have trim tabs

 

[Canso]

Personal experience here. Keep in mind that although your podded OB is lighter than your I/O, the mass is way further back.
My 622 porpoises like a bugger. Playing with some math, I realized that the lower mass OB sitting further back from the centre of mass of the boat effectively levered the bow up. Now I am trying to move my batteries into the cuddy area in order to rebalance the entire boat.

props make a big difference in handling, try a stern lifting prop before you move weight around. A 4 blade with less rake is what your looking for.
http://continuouswave.com/whaler/reference/prop3.html

 

[salmonkiller01]

Can you not deal with the porpoising by adjusting your engine trim or using your trim tabs?

You can somewhat control using both engine trim and trim tabs, but only to a point as you increase drag. If your porpoising, tuning engine height can make a huge difference. I need to raise my outboard as it porpoises around 35 mph, I cruise around 30 sio it is not an issue, but it needs to be raised

 

[Wild Bill]

What about this one. Seen lots build this way minus the side pieces from the floatation chamber and no complaints.

NDT, so if those gussets in your pic are intended to look like this, while it is a strong design.

The thing I like about a swim platform attached to the transom is it becomes a huge structural member.

 

[NDT]

NDT, so if those gussets in your pic are intended to look like this, while it is a strong design.

The thing I like about a swim platform attached to the transom is it becomes a huge structural member.

I agree, haven't fully decided how the platform will be yet, I'd feel safer if it was bolted to the transom. This away the swim platform mounts will be above the water as well.
Just waiting for the aluminum now and then the centre portion will be built, then figure out the platform and its mounts

Thanks for the input, I did notice most bracket pics on this site are bolted along the transom.

 

[NDT]

Also, I've messed around trying to rotate my avatar pic... Gave up, I guess it's time to find another pic lol