Author |
Message |
JBSedon
MMT Member
Joined: Tue Jul 05, 2011 11:55 am Posts: 25
|
 Shaft Length Question
Hey guys!
I'm getting ready to build a longtail. I picked up a Kohler Command Pro 25 motor yesterday. Doing the hone, rings and seals this week just for good measure. No mods planned since its a longtail, except for an exhaust. I'll build that later though. Doing a tubular frame design. No hull for it yet, I'll get to that later too, but I'm planning on something along the lines of 1442. This is strictly a small river duck rig.
Couple quick questions.
Is 15 degrees the max downward angle for the shaft due to the joint efficiency?
What are the factors determining whether I should go with a 59" or 72" driveshaft?
I was planning on a 72" until I saw the SWOMP with a 59", and it peaked my curiosity. I like the idea of the 59", but don't know what it affects.
|
Sun Jan 18, 2015 8:40 pm |
|
 |
Kcpanages
MMT Addict
Joined: Sat Dec 13, 2014 5:41 am Posts: 532
|
 Re: Shaft Length Question
59", UR limited on transom height, 72" gives u a better range for transom height and a lil more reach
Sent from my iPhone using Tapatalk
|
Mon Jan 19, 2015 12:26 am |
|
 |
JBSedon
MMT Member
Joined: Tue Jul 05, 2011 11:55 am Posts: 25
|
 Re: Shaft Length Question
Is 15 degrees the max downward angle?
Is there a performance difference between the 59 and 72?
|
Mon Jan 19, 2015 12:32 pm |
|
 |
FRANKtheTAU
MMT 1000 Club
Joined: Thu Dec 29, 2011 10:30 pm Posts: 1386 Location: West TN
|
 Re: Shaft Length Question
15 is max. 59" shaft creates less tiller torque. And as far as the 59" shaft being at a disadvantage because it's shorter, I personally have never thought, "Damn I wish I had the 72" driveshaft".
_________________ 40 Backwater SWOMP Lite / 1752 Alweld Mud
6.5 Backwater SWOMP Lite / 1440 PolarKraft
|
Mon Jan 19, 2015 3:01 pm |
|
 |
da go get'er
MMT 1000 Club
Joined: Wed Oct 27, 2010 8:30 am Posts: 3406 Location: Prairieville
|
 Re: Shaft Length Question
In the same height transome a 72 is faster
_________________ 17*38 Klibert 23GDLT I toast to staying positive and testing negative!
|
Mon Jan 19, 2015 4:29 pm |
|
 |
JBSedon
MMT Member
Joined: Tue Jul 05, 2011 11:55 am Posts: 25
|
 Re: Shaft Length Question
Faster you say? Is it a noticeable difference in speed?
72" just seems like so much tail out the rear of the boat. I'm located in Ohio, going to be running mostly rocky rivers and I do not want a jet. I will also be running muddy backwaters and lilly fields on some lakes and rivers.
|
Mon Jan 19, 2015 4:47 pm |
|
 |
Kcpanages
MMT Addict
Joined: Sat Dec 13, 2014 5:41 am Posts: 532
|
 Re: Shaft Length Question
|
Mon Jan 19, 2015 9:28 pm |
|
 |
139sst
MMT Pro Member
Joined: Thu Feb 16, 2012 4:02 pm Posts: 202
|
 Re: Shaft Length Question
You will better served to get at least a 1542 with that 25. The 1442 runs better with a lighter load in the back. Slow turns could be a little sketchy.
|
Tue Jan 20, 2015 6:59 pm |
|
 |
da go get'er
MMT 1000 Club
Joined: Wed Oct 27, 2010 8:30 am Posts: 3406 Location: Prairieville
|
 Re: Shaft Length Question
_________________ 17*38 Klibert 23GDLT I toast to staying positive and testing negative!
|
Tue Jan 20, 2015 7:07 pm |
|
 |
Glades Ranger
MMT 1000 Club
Joined: Mon Sep 19, 2011 6:32 pm Posts: 1490 Location: south Florida
|
 Re: Shaft Length Question
Not to hijack this, but Frank the Tau, if I upgrade from a 27 HP LT to the Swamp 35 SS, on my grizzly 1648, should I get the 59" or regular length 72" model? I like the idea of a shorter turning radius, but I am 25 years used to the 72" model. As I am hitting 61 this month, less tiller torque is welcome, but as da go get'er stated, how much of a speed loss with the 59" drive? Either way, I am almost sure I am going with BackH20's product!
_________________ Sailing in the sawgrass /1648 grizzly and Swomp 26.5 EFI
|
Wed Jan 21, 2015 3:10 pm |
|
 |
FRANKtheTAU
MMT 1000 Club
Joined: Thu Dec 29, 2011 10:30 pm Posts: 1386 Location: West TN
|
 Re: Shaft Length Question
If you have a 16" transom, I would run the SS. Jake and Arlon have both told me that benefits of the easier driving of the SS model FAR outweigh any miniscule speed increases you may see from putting an LS on a 16" transom. And I'm running over 26 mph with my set up. That is plenty for me.
_________________ 40 Backwater SWOMP Lite / 1752 Alweld Mud
6.5 Backwater SWOMP Lite / 1440 PolarKraft
|
Wed Jan 21, 2015 6:25 pm |
|
 |
Glades Ranger
MMT 1000 Club
Joined: Mon Sep 19, 2011 6:32 pm Posts: 1490 Location: south Florida
|
 Re: Shaft Length Question
Loud and clear, Frank! Thanks! I will have to wait another season, but I look forward to the upgrade!
_________________ Sailing in the sawgrass /1648 grizzly and Swomp 26.5 EFI
|
Thu Jan 22, 2015 5:17 am |
|
 |
|