32 Active Thunder

Has anybody converted an IO boat to outboards?? What are the rule of thumbs for horsepower on outboards vs Big Blocks?? Any pics of boats with outboards please post thanks!!

BoatShow239

Not aware of a power slide chart for conversion of IO to OB, but it is a somewhat common occurence.

You are sort of asking a wide open general question.

I know I am missing something, but there are a number of things which need careful inspection, if not rebuilt. Transom, knees, stringers, corners, cap.

Seldom are OBs directly mounted to the transom, so a decision needs to be made which style of mounting you wish.

Mounting OBs also opens up a vast array of pocketing possibilities

I am sorry I really haven't addressed your principal question, but for the most part since this is a performance boat forum, I would think you might hang as big a motor(s) as you have room, boat size and bank account for!

HTRDLNCN

On larger offshore boats (27++ deep vees) OBs will run pretty much same talking apples to apples.
Meaning a boat with twin 300hp I/O will run roughly about same with 300hp OB
I know on the Carrera 27s like mine the ones with twin 300hp small blocks ran same as twin 300 OBs
though not as well balanced in my opinion.
After that things get not so clear..
Problem is with OBs you are limited to about 300-350 an engine, only way to get more is to put
more engines, this creates drag in the water from the extra gearcase which robs some of that
new found power, thus a triple 300 OB may have 900hp but will be slower than a twin 450hp I/O.
Some guys even go with 4 or 5 outboards but again the more gear cases in the water the power it takes to push them. 4 300hp would put you at 1200hp but you would not be anywhere near as fast
as twin 600hp I/Os..
Some boats are excellent OB material, Cats for one love them especially the smaller lighter ones.
Most Center Consoldes are OB powered, forgetting about the fishing side of it most peaple get CCs
for partying, taking the motors outside the boat opens up a huge area.

Other things to consider is cost, typical 300-350hp OB runs 15-20k, about same as a 496/bravo setup,
Not bad if you stick with 2 of them but once you start running 3-4 pf them it adds up quick.

You are moving all the engine weight further back, this can adversely affect your ride in rough water.

If you also like rafting up and hanging out you will have no swim platform space , even with just 2 OBs
you will have to jump around them. Means everyone on your raftup will be walking on your boat
to get by instead of the platform.

Just random stuff I could think off..
If you have an Active Thunder 32 like your name says triple 300s will get you in the low to mid 70s,
youll cut back on gas use probably by 20-25% and the conversion will probably run you around $75k
using new motors+bracket+controls,+steering+etc..

thirdchildhood

iTrader: (6)

I can think of several advantages that should more than off-set the above mentioned issues:

Power to weight ratio.
Center of gravity moved rearward.
Less parasitic drag due to only one change in direction of power & no u-joints.
Ability to install and use hydraulic jackplates.

rchevelle71

iTrader: (1)

You missed one............

The ability to stand upright with a beer in one hand while wrenching on the motor, not that it is needed that often with a 2 stroke OB, which brings up another one, no oil changes

speicher lane

try Checking out :

http://www.armstrongnautical.com/brackets.htm

When my father was looking for a walk around 26-30' fishing boat, we sea-trialed 2 boats that were the same hull - only diff. was the one was rigged single 260 hp I/O and the one he bought was the 225 single OB on the bracket... more use of space in the cockpit, easier to work on and the boat handles like it is 2-4' longer model and jumped on plane quick. They were within a 1-2 mph of each other if I recall correctly as the dealer had them propped ( S/S on OB and alu on the I/O)...and the I/O had tabs (Possible factory option????) - OB boat never had reason to put them on

It is a heavier fishing boat not a high performance hull so I can not say if it is still apples to apples...

Armstrong was really good to deal with regarding technical questions.

Just putting this out there, the Ocean Hawk/Cig Cafe CC and the Cig Decathalon are rigged on brackets - what other boats used these hulls for in I/O applications?

BoatShow239

More and more of the OBs are 4 stroke and likely in the not too distant future the selection of 2 stroke OBs might be (even more) extremely limited.

What 4 strokes give up in hole shots, they more than make up in fuel economy and quiet.

As mentioned, mounting brackets are the way to go. They get the prop away from the boat so it can be higher and more control to incrementally raise the prop out of the water and run shallower.

With some pocket configurations the skeg(s) run higher than the keel of the boat. Can cause issues with cavitation on turns, but properly designed it is really not that great of an issue.

JUPITER PULSARE

Outboards give you alot more flexability, weight savings, and cockpit space. The 2-stroke outboards have become fairly fuel efficient and quiet. They are easier to work on with less grease in the bilge. Some manufacturer have done well with ouboard sportboats. Velocity, Concept and Checkmate to name a few. Active Thunder also finished a new 33 with outboards. The ability to install hyd. jackplates for motor height adjustment and better performance is one big benefit. I'm in the process of renovating a 28' Checkmate with twin outboards. Here's Checkmates latest outboard model:
http://checkmatepowerboats.net/Check...-OBX-2800.html

32 Active Thunder

Hey good advice on this stuff!! My plan would be to install the outboards with a bracket not directly to the transom. I did have a 32 active thunder Face Off sold it two years ago then was told bank took it then went to auction don't know who has it now if anyone knows let me know!! The active thunder was a perfect boat I'm just sick and tired of working on IO's and the fuel it cost to run these boats I know you have to pay to play I understand that but outboards just seem the way to go!! I look at it this way if I blow an outboard I can purchase another about anywhere take it off myself and be on the water the next day!! Also speed is not a big issue with me not anymore anyways. So if I buy a hull that has the motors out of it what would be the steps to putting on outboards with brakets?? Thanks you guys its good to be back on offshoreonly again also any pics would be nice!!

rchevelle71

iTrader: (1)

Glass in the transom, hang a bracket, run some wires, and steering, install gages and controls if they are not already there, pretty easy stuff.