What are Stumble blocks and what do they do

[teddy dauphinee]

I have heard and seen these but don't really know what they are for and why they are where they are.

Stumble blocks under a tunnel hull.

Why are they put on a boat?

What do they do?

How do you know how wide and how long to make them?

 

[lohring]

Stumble blocks limit the amount the bow can come down in the turn. This keeps the boat from hooking. I think Rod Gerraghty came up with the idea quite a few years ago.

Lohring Miller

 

[VansRacing]

Lohring is correct. Rod came up with that years ago and it was a great idea. We call them "Rod blocks" here in our area. They work. When I am testing a new hull, I take 6 or 8 sets of them with me and change them out to get the best set.

-Carl,

 

[Bill Gibson]

Its best to make up some different sizes and shapes and test em....I use double sided tape to attach em....its kinda funny in that at one time stumble blocks were regarded as a "crutch" due to a poorly designed hull...now lots of boats use em! Your trying to find that line where the boat will turn well and not hook, but will not slide out of the turn also....