Re: ABC Sib-Rib Installation Guidelines.-
I have a feeling that alanfox is talking a completely different situation than a thread that was meant to help normal inflatable motor installations.
If the motor was run on a pontoon with an 8" pitch prop but 15" is the recommended for normal service, he has a bit of horsepower on his hands. Talk of raising the motor and others using low water pickups indicates he plans on shallow water running which is a whole different kettle of fish than normal inflatable boating.
A bracket on a full inflatable would be problematic if the boat were folded, so he must have a RIB with a fairly large motor. He probably has a fairly special situation he is working on, but it would be doubtful if it falls into the range of general inflatable boating where shimming or cutting a transom is definitely recommended.
Although I highly doubt the installation alanfox is contemplating has much to do with normal inflatables, we would like to hear just what it is? Sounds interesting even though not associated with the recommendations for general boating in this thread.
Let me chime in here as Sea Rider suggests. First, Sea Rider I appreciate everything you have taken the trouble to write about on this subject and find it all to be useful and and valid information. Second, how both of you can read what I've written and make the assumptions you have is beyond me.
I have a 2013 Sea Eagle 14SR which weighs about 170lbs total and is rated for a 40 hp motor. My motor is a 1997 Mercury 30 hp which is basically the same as their 40 hp of that year. Being that it's the same motor as the 40 hp its a large 30 hp of about 650cc's and weighs 155lbs. Most 30 hp two strokes have been about 500cc so I'm assuming mine will have more torque than the 500cc motors. The motor has a 20in shaft and my boat has a 15in transom. This is a remote motor so I have a steering wheel and controls for it.
I am not a "go fast person" I'm mostly a go slow person that wants his boat and motor to be operating at its best. Peak miles per gallon rather than go fast is much more important to me. I use my boat for cruising,exploring,scuba diving and fishing...nothing other than general boating wouldn't you say?
I needed a way to use a 20in shaft motor on a 15in transom and I found an easy simple solution was to use a jack plate. It is a simple light weight jack plate and I'm sure it will work good for me. I thought it would be a simple solution for others also so that really was the whole point to my reply. Another point I made was there are a number of things that go into getting peak performance from you boat/ motor combination,meaning more than just "go fast",one of them being prop pitch. I used as an example props and pitches from different ends of the prop spectrum and where mine should probably be for my boat and boating needs.
For me a jack plate is a good solution to my problem while nether suggesting or implying it's a solution for everyone's motor installation issues. I roll my boat up twice a year and it's a simple thing to unbolt four bolts and take the jack plate off before rolling it up. Sure, if you had to do it every time you went boating it may not be the solution for you but it is one option to think about. Hopefully my chiming had cleared up your confusion.
Then you cross your fingers, slow down and hope the hub holds until you reach calm water.
