15" mid vs 20" on XB2003

[85allison]

Just a general question. What are your opinions on running a 15" motor on an XB2003 vs a 20" motor. I have always run 15" stuff on all of the 02 hulls and now have an XB03 with a 20" offshore. What would the difference be aside from the motor taking a bath.

 

[K.Kiser]

Lose a little weight, and maybe limit how high you can trim

 

[rmills280]

I ran one on a 03 for 7 yrs and loved it, was never a issue dunking the motor

 

[BP1]

Had 15 on mine and never dunked either. Flotation in the jackplate will help.

 

[Waterboy334]

Good question. I've considered going to a 15" on mine.

 

[DieTryin]

For you guys who say dunking the motor isn't a problem, did you run hydraulic jack plate? I'm also considering a 15" mid but I don't want to run a hydraulic plate.

 

[wasmeneh]

I have been thinking of one also. My manual plate is almost maxed out for height. Can somebody advise what the switch would entail? Right now I'm running a stock 200 with at CLE.

 

[BP1]

I did not run a hydro plate, but a hydrodynamics that was made for a 15" mid.
Something to consider when switching over from a 20",is most jackplates wont get the motor low enough on the transom.

 

[K.Kiser]

Yes, will require a jackplate made for a 15" mid.. And if a 15" doesn't dunk the PH on an xb02 then it won't dunk on an 03

 

[h2oskiier30]

Yes, will require a jackplate made for a 15" mid..

Or the knowledge of how to modify your 20" Allison jackplate to work with a 15" mid.

 

[David Lanham]

Had a 15 on mine once and dunked it, destroyed the motor. Was bad timing of events, full fuel, live well full, huge waves, trim tucked it. Hydro locked coming off plane. Pretty sure if I had skid planner on or a tail it would not have done it.

 

[whipper]

Theoretical Q about 15 or 20 inch mid. Not that it matters a whole lot on an Allison but wouldn't a 15 inch mid be stronger than a 20 inch mid? Also as mentioned a 20 inch mid is a lighter motor because the clamp is beefier. Ive also read some were the 15inch mid is actually a heavier can than for instance than a 20 inch Bass can is that correct? Speed wise they would both be the same on an 03 but maybe a 15 would be faster on an 02 because at the higher speeds of an 02 the cowls extra 5 inches taller effects aerodynamic more so not realized as much on an 03,s top speed as much?

15 inch has cool factor and less tilt when trailering also. Not sure about the leverage differences on over all hight verses setback but a 15 may have less stress on the transom because you dont have to set back the jack as far because the 15 has more setback built into the clamp and bracket. pros and cons to both perhaps.

 

[whipper]

Or the knowledge of how to modify your 20" Allison jackplate to work with a 15" mid.

Dont you flip it around? Ive heard something about this before?

 

[Darth VMAX]

Also as mentioned a 20 inch mid is a lighter motor because the clamp is beefier. Ive also read some were the 15inch mid is actually a heavier can than for instance than a 20 inch Bass can is that correct?

I have heard that this as well and that the 15" SS motors being lighter than the 20" motors was a misconception.

 

[K.Kiser]

Yes, some of the Allison plates are convertable and all are modifiable if the know how and tools are there.. I'm gonna modify mine, but we have a running machine shop in my dads back yard and he has decades of .0000" experience but recommending someone buy the correct factory made jackplate is my friendly disclaimer

 

[K.Kiser]

Whipper, not all the plates are convertable.. I think the earlier made plates are set as is

 

[whipper]

Good info, just remember wanting to do this also and going threw all these pros and cons is why I knew some of it . Thanks for verifying.

 

[ziemer]

Yeah, the 15" offshore mid is basically the same weight as the 20" OS mid. The clamp bracket makes up for the weight lost by cutting 5" out of the can.

I've had mine for several years and have not had any problems with dunking the motor. I've also had 4+ people in the boat with a full load, and no issues. You just can't let off the throttle...ease it down and it's fine.

I think the boat definitely drives a little better with the 15 over the 20 too. Dropping the weight down helps.

However, it's an expensive swap. $2500 min for a nice 15" mid/clamp, new or cut down driveshaft and shift shaft, new or modified jack plate (unless you have a newer Allison plate), etc...

But it is definitely cooler looking.

 

[procomp]

I used a hydrodynamics rapid jack and went through a bit of a learning curve with them. The one you need comes straight back off the transom unlike the one required for an STV that comes down off the transom.

FYI - The 20" motor jackplate plate has a slight rise to it when coming off the transom.

 

[DieTryin]

I was thinking about using Calhoun Marine. They have a mid section cutting service for $750 plus the cost of shortening the drive shaft.
http://www.screamandfly.com/showthread.php?245049-lt-lt-lt-Mid-Section-Cutting-Service-gt-gt-gt