Lower Units/ K@B vs. Lawless

[ggillman]

Ok Tunnel Dudes,

After reading the Hooking Hopper post, how about a discussion about the subject of lower units?

To me the further you place a prop from the transom, the more leverage you get as the hull turns, leading to hooking, flipping and transom lift, worse if ya are using a mod 1440.

I have ran both types and the sweet spot for me with the stock K@B was about 5 to 5 1/2 inches, transom to drive dog.

So what ya think here? Comments, Opnions, Suggestions.

Also NR has a still different lower unit on their 3.5 outboard, anyone tried one of those out?

Gene ;D

 

[Jerry Dunlap]

I like the LawLess Outdrive , however, on boats where I'm running a LawLess OD, I insert the transom so the propeller is the same distance from the back of the boat as a K&B lower unit. This is easily done on custom built wood boats. It's really not an option on fiberglass/plastic boats.

It has been my experience that placing the propeller back to far causes handling and trim problems.

The lower unit on my HTB 290/CMB 21 LS Greenhead is a K&B 3.5 lower unit. I am using a LawLess OD?CMB 21 Gold Head on my new 29.5" hull(featuring some Villain S1 design concepts) and the transom is 1 1/2" forward of the back of the sponsons. I tested the boat on Thursday, but the wind was blowing so hard all I did was bounce over the water.

Jerry Dunlap

 

[TimD]

"Also NR has a still different lower unit on their 3.5 outboard, anyone tried one of those out? "

Gene, do you mean ROSSI?

I have done some testing with the spacing issue and it does seem to differ from hull type to hull type. My 21 tunnel seems to like a 6 inch rear edge to drive dog spacing. I like the lawless because of the flex shaft angle being less - kinder on the shaft and gives a better alignment into the PTO and the propshaft assembly. This would have to be more efficient than the K&B shaft.

 

[ggillman]

Oops, Yeah the new one on their 3.5 outboard, It has a different design than the K@B or Lawless.

Gene ;D

 

[Grimracer]

Dudes

Are we talking about the Bullet Drive? If so I have seen them run but have no opionion at this time. It does however look like it could have some of the same dims as the K+B lower unit.

Also I beleve the unit is cast like the K+B, and you can not replace the skeg. It is also a 90 deg unit like the K+B.

Some time soon we will have to get Brian Nelson involved in this as he has molds for an plastic injected lower unit. "I think" Or he has worked on a set.

I would love to see this as the weight savings would be huge.

Did i get off track? :-

Grim

 

[ggillman]

Sounds like the correct one to me,

The injection molded unit sounds like a good idea also,

The trick would be to find the right material to use for durability.

I think yer on the right track Grim, There would be a big difference in weight.

Gene ;D

 

[TimD]

Injection moulded lower unit sounds cool 8) 8) would be a lot cheaper to make than a machined unit like the Lawless.

The bullet drive looks like it would be a heavy item - anyone know if that is the case?