I’m looking to install a shoe/ride plate on my intake before I put it back in the boat and have a few questions.
1) when machining for the shoe, is the shoe mounting plane (yellow line) parallel to the hull mounting surface (red line)?
Almost always, yes. That will also make the shoe surface 4-degrees to the suction housing gasket surface.
2) let’s say my shoe is 1/2” thick, so I only remove 1/2” of material from the intake? That way I’m starting from 0 when adding shims.
That's really not the right way to think about it. EVERYTHING is relative to the keel. Again, what kind of boat? Every intake install is different. If you wanted to start with a guess, a 5/8" shoe is a safe bet. I wouldn't do a half inch shoe, but it comes back to what is the hull?
It sounds to me like you have the technical savvy and the tools and machinery to do the work. I would not make the shoe until after you have the intake set in the hull. That way, you can actually measure your biting edge depth and make the shoe accordingly.
Ideally, for a back cut shoe, you would want the end of the back cut, just in front of the ride plate, to be even with the keel. This is a "safe" yet aggressive setup.
You should also make a selection of shims to increase your biting edge depth. Your shim set should also include ride plate shims. Whatever change you make to your shoe shims, you need to make the same change to your cradle and ride plate, otherwise your ride plate angle changes.
You will want enough shims to bring your biting edge depth even with your keel. Typically shims are 1/32", 1/16", and 3/32" thick. How many shims you need are relative to how ambitious you are about "dialing in" your boat. Most people are satisfied with the "safe" setup and never add any shims. A few people will end up with a whole case full of shoes and shims.
Be advised, DON'T start out with every shim installed. Gradually add shoe depth and thoroughly test to verify that your boat is safe and wants more shoe depth. The more shoe depth you add, the more dangerous your boat becomes.
3) as far as the ride plate, any angle will be determined by the cut on the rear of the shoe?
It depends on the type of boat.
A V-bottom hull will start out with 4-degrees (safe) ride plate angle and may approach a 6-degree (kill) ride plate angle. I would most likely start out with a 2-degree ride plate step in the shoe.
In a tunnel hull, the step would probably be zero or 1-degree max.
These angles are guidelines and many factors need to be considered. There is no such thing as one-size-fits-all. There is "good enough for most" and "pushing the edge of performance" as well as all levels of in between.
Thanks in advance
John
Hope this is helpful.
Cheers,
Joe
