Lip on XB21 Boats

[xb03fs]

80 is like nothing. 65-70.... that's another story lol

65-75 is my least favorite speeds in a allison. Both boats that seems to be the transitioning area requiring the most input

[K-DAWG]

65-75 is my least favorite speeds in a allison. Both boats that seems to be the transitioning area requiring the most input

Yep, that's about what I think. Once you get above 75 I feel much safer. Low 70's seems to take a lot of work to keep her flying straight.

[xb03fs]

Driving Geoff 300 was great with 2 people and powerpoles it ran to 90 like my 250 runs to 85... so effortless.

[NOTGSXR]

65-75 is my least favorite speeds in a allison. Both boats that seems to be the transitioning area requiring the most input

You're right.. I usually breeze past 75 asap..... 80 - 90 is super smooth.

[xb03fs]

You're right.. I usually breeze past 75 asap..... 80 - 90 is super smooth.

The 300 makes 90+ that silky smooth. The extra hp is nice. Never even thought about 300s till a couple months ago

[hooken203]

.030 was removed from the lip on my boat by the main pad sander at Allison boats. It made a big difference in bow lift. My boat will run 70 as smooth as butter. I think you could get on the back deck and take a nap at 70.

[Strokerdean]

Johnny, thanks for the reply. I am by no means a Engineer or Boat designer, my back ground is aviation, drag racing cars and ski racing boats. Logically thinking I would believe a lip in the rear of the pad would act like a hook on the pad. I've always been under the impression that a hook on the bottom causes handling problems. Am I looking at this the wrong way? Could it be that the lip is so slight that there isn't a hook affect and it just changes the ride/handling characteristics. Could the long keel of the Alli be the reason for a lip from the factory? Again I would think with the long keel the lip would try to push the bow down. I enjoy reading the Allison forum and am not trying to create any hate or discontent as I am just curious why the pad has a lip and what it does.

The hulls on the XB21's are pretty much identical "except" the height of the lip. I think Darris plays or played with the lip to achieve various performance from the different models. I have been told there are 2 molds at the plant. Each mold has a different lip from one another. I know one boat that almost has no lip. It sure seems to run great. It has top end speed and handles well enough. Hole shot is good too. But the guy with that boat may have a lighter setup than many others.

[xb03fs]

My opinion only:

The lip lift the rear helping the boat run flatter for better aero dynamics.

It lifts the rear earlier helping the boat clean up faster to accelerate better

Helps keep nose planted in rough water

Help raise stern in hook situations to realease rear of boat keeping a hook a hook and not a barrel roll

[NOTGSXR]

My opinion only:

The lip lift the rear helping the boat run flatter for better aero dynamics.

It lifts the rear earlier helping the boat clean up faster to accelerate better

Helps keep nose planted in rough water

Help raise stern in hook situations to realease rear of boat keeping a hook a hook and not a barrel roll

Interesting thought about the barrel roll nathan... some think the lip is the possible cause of said hook..

[K-DAWG]

Also, I have read from different threads on different occasions some of them here some on A-Owners. That the more HP you have the less lip you need. The lip helps boats with less power get the boat up out of the water so it runs faster. I cannot tell you if that is true or not only what I remember reading on the multiple threads I have seen on this subject over the years.

[Tim Powell]

65-75 is my least favorite speeds in a allison. Both boats that seems to be the transitioning area requiring the most input

Ive not seen this in any of the boats that I have driven. However I am mostly a 2 seater guy.

[tritontr21]

Ive not seen this in any of the boats that I have driven. However I am mostly a 2 seater guy.

Have you ever driven at that slow of speed

[Tim Powell]

Have you ever driven at that slow of speed

Thats a good question

[Johnny Maxwell]

Johnny, thanks for the reply. I am by no means a Engineer or Boat designer, my back ground is aviation, drag racing cars and ski racing boats. Logically thinking I would believe a lip in the rear of the pad would act like a hook on the pad. I've always been under the impression that a hook on the bottom causes handling problems. Am I looking at this the wrong way? Could it be that the lip is so slight that there isn't a hook affect and it just changes the ride/handling characteristics. Could the long keel of the Alli be the reason for a lip from the factory? Again I would think with the long keel the lip would try to push the bow down. I enjoy reading the Allison forum and am not trying to create any hate or discontent as I am just curious why the pad has a lip and what it does.

Dean you are 100% correct in that the lip is a drag, or hook if you will, on the rear of the boat. It will and does cause the stern to lift. When the stern lifts then naturally there will be some bow lift. I think that both hydrodynamic reactions (bow and stern lift) are great in the right measure. I'd rather have too little lip than too much. If your running WOT and have to let out of it with a tall lip, that bow will take a dive. Ask Powell about that experience once upon a time. LOL

[Strokerdean]

That's what I have heard. I have one more question. With a smaller lip will you get more bow lift(flying the nose) and run flatter with a larger lip. I have seen some alli's run a high bow wile most run pretty flat. Thanks for all the input, I try to be helpful when I can and want to learn what I can.

Dean you are 100% correct in that the lip is a drag, or hook if you will, on the rear of the boat. It will and does cause the stern to lift. When the stern lifts then naturally there will be some bow lift. I think that both hydrodynamic reactions (bow and stern lift) are great in the right measure. I'd rather have too little lip than too much. If your running WOT and have to let out of it with a tall lip, that bow will take a dive. Ask Powell about that experience once upon a time. LOL

[tritontr21]

That's what I have heard. I have one more question. With a smaller lip will you get more bow lift(flying the nose) and run flatter with a larger lip. I have seen some alli's run a high bow wile most run pretty flat. Thanks for all the input, I try to be helpful when I can and want to learn what I can.

That is the general rule of thumb. I do believe prop, load, driver style and comfort level plays into it as well.

[Johnny Maxwell]

Setup us a very big deal as all of us probably can attest. Prop, motor height, trim, weight distribution, etc., and lip. It's like putting makeup on a woman. She can look ok without it but can look like a model with it. You can cover up a lot of flaws in a hull with some awesome setup and driving skills, but just like some women have natural beauty and don't need makeup, some boats, when all the parts and pieces are set right, don't need much input from the driver to be an incredible ride.

[fishnfireman]

Setup us a very big deal as all of us probably can attest. Prop, motor height, trim, weight distribution, etc., and lip. It's like putting makeup on a woman. She can look ok without it but can look like a model with it. You can cover up a lot of flaws in a hull with some awesome setup and driving skills, but just like some women have natural beauty and don't need makeup, some boats, when all the parts and pieces are set right, don't need much input from the driver to be an incredible ride.

Well put --- Even I can understand that.

[xb03fs]

Setup us a very big deal as all of us probably can attest. Prop, motor height, trim, weight distribution, etc., and lip. It's like putting makeup on a woman. She can look ok without it but can look like a model with it. You can cover up a lot of flaws in a hull with some awesome setup and driving skills, but just like some women have natural beauty and don't need makeup, some boats, when all the parts and pieces are set right, don't need much input from the driver to be an incredible ride.

I think mine is like this. It is incredible. My bottom was essentially blueprinted a few years ago by Allison after I hit a stump and knocked some gel off. It drove good before but it may be even better now.


Only have s 6” straight edge will try to get another but I need
Some smaller bits. Smallest I had was 3/32 and it is still a little thick.

I am going to get some smaller bits and a longer straight edge... but mine is going to end up 5/64 or 1/16” I am positive...

My lip is also not reall a lip but more of a 1” wedge... I know some are a very short lip...

[catfish123]

I think mine is like this. It is incredible. My bottom was essentially blueprinted a few years ago by Allison after I hit a stump and knocked some gel off. It drove good before but it may be even better now.


Only have s 6” straight edge will try to get another but I need
Some smaller bits. Smallest I had was 3/32 and it is still a little thick.

I am going to get some smaller bits and a longer straight edge... but mine is going to end up 5/64 or 1/16” I am positive...

My lip is also not reall a lip but more of a 1” wedge... I know some are a very short lip...

Very interesting that when they blue printed the bottom, they apparently made your lip entirely different than the lip that comes from the molds from your description of it. I know a person who had their lip on an XB2003 totally redone at the factory and the boat was not driveable afterwards.