97' Sylvan SE Center Toon Addition

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   Hey all

My father and I purchased a 1997 24ft long Sylvan pontoon two years ago. It gets most of it use up on Lake Geneva in Wisconsin which can be quite wavy, especially on the weekends. So this year we decided we were going to add a third pontoon for more flotation and a better ride. I figured I would post everything up in case it could help someone with their conversion in the future.

This is the best photo I have of the boat. Since then, We have redone the seats, electrical, outboard, lighting, added a staircase to the trailer and started revamping the playpen skin.

IMAG0021 by scott011422, on Flickr

And a mockup:
Untitled by scott011422, on Flickr

Had the Donor toon delivered from Great Lakes Skipper. Its a Bemmington 25.5ft oval toon.

Untitled by scott011422, on Flickr

Untitled by scott011422, on Flickr

This toon is off a canceled special order. You can order any 2 toon boat with optional 32" oval logs. However, being its for a 2 toon boat, no integrated transom. So I purchased myself a TIG welder and am teaching myself to TIG Weld. Going to make my own transom. Since I'll be cutting off the back of the toon, its a good time to add a larger fuel tank too. We will be removing the factory 26 gallon tank off the deck which then gives us more storage space, and mounting a 49 gallon in the toon. To get the most out of this tool i am designing the transom to be 100% sealed for maximum flotation. All said and done, this should add roughly 1400 pounds of flotation on a normal outing with a maximum of 4000lbs when fully loaded. Here are my current designs:

Untitled by scott011422, on Flickr

Untitled by scott011422, on Flickr

Untitled by scott011422, on Flickr

I will be using 3/16 Aluminum plate for the outer skin and 2"x 4" 1/4 wall tubing backing that up. I'll also have 3 1/4 thick plates that will be welded into the tubing and outer skin that will be welded onto the skin to help take up the stress from the outboard thrust.

Edited by Scott011422 - 05/16/2018 at 12:53pm

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Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Topic: 97' Sylvan SE Center Toon Addition Posted: 04/23/2018 at 5:55pm
	Hey all My father and I purchased a 1997 24ft long Sylvan pontoon two years ago. It gets most of it use up on Lake Geneva in Wisconsin which can be quite wavy, especially on the weekends. So this year we decided we were going to add a third pontoon for more flotation and a better ride. I figured I would post everything up in case it could help someone with their conversion in the future. This is the best photo I have of the boat. Since then, We have redone the seats, electrical, outboard, lighting, added a staircase to the trailer and started revamping the playpen skin. IMAG0021 by scott011422, on Flickr And a mockup: Untitled by scott011422, on Flickr Had the Donor toon delivered from Great Lakes Skipper. Its a Bemmington 25.5ft oval toon. Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr This toon is off a canceled special order. You can order any 2 toon boat with optional 32" oval logs. However, being its for a 2 toon boat, no integrated transom. So I purchased myself a TIG welder and am teaching myself to TIG Weld. Going to make my own transom. Since I'll be cutting off the back of the toon, its a good time to add a larger fuel tank too. We will be removing the factory 26 gallon tank off the deck which then gives us more storage space, and mounting a 49 gallon in the toon. To get the most out of this tool i am designing the transom to be 100% sealed for maximum flotation. All said and done, this should add roughly 1400 pounds of flotation on a normal outing with a maximum of 4000lbs when fully loaded. Here are my current designs: Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr I will be using 3/16 Aluminum plate for the outer skin and 2"x 4" 1/4 wall tubing backing that up. I'll also have 3 1/4 thick plates that will be welded into the tubing and outer skin that will be welded onto the skin to help take up the stress from the outboard thrust. Edited by Scott011422 - 05/16/2018 at 12:53pm

curtiscapk Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 01/30/2013 Location: OP KS \Truman Status: Offline Points: 982	Post Options Post Reply Quote curtiscapk Report Post Thanks(0) Quote Reply Posted: 04/23/2018 at 10:05pm
	can't wait to see this! Great stuff!
	Craig n Paula THE FLOATER Rebuild 94 Party Barge 24' 115 merc 22mph OP KS Truman Lake

gerard143 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 07/20/2017 Location: NY Status: Offline Points: 58	Post Options Post Reply Quote gerard143 Report Post Thanks(0) Quote Reply Posted: 05/13/2018 at 4:56am
	ya excited to see where this goes.... keep us posted!

Bansil Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 11/03/2016 Location: TN Status: Offline Points: 4	Post Options Post Reply Quote Bansil Report Post Thanks(0) Quote Reply Posted: 05/14/2018 at 8:56pm
	I guess I am #3 to this party

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 05/16/2018 at 12:48pm
	Enough of the Fuel tank mount is designed, material ordered. Going to weld a frame to the bottom of the tube. There will be a lip sticking down on the far side of the tank mount that will slide under the tank frame so I can slide the mount onto the frame and then either bolt or weld the aft section of the mount to the frame. Untitled by scott011422, on Flickr

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 11/14/2018 at 12:37pm
	So i finally got to work some on my toon. Was able to remove the engine and transom. Then slid the centertoon in for some mock ups before i cut her open. Some creative strapping and a chain hoist make easy work: Engine comes off by scott011422, on Flickr Engine comes off by scott011422, on Flickr Engine comes off by scott011422, on Flickr Engine comes off by scott011422, on Flickr This is about how far it will stick out: Engine comes off by scott011422, on Flickr

curtiscapk Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 01/30/2013 Location: OP KS \Truman Status: Offline Points: 982	Post Options Post Reply Quote curtiscapk Report Post Thanks(0) Quote Reply Posted: 11/14/2018 at 9:37pm
	Nice where'd you get the tube?
	Craig n Paula THE FLOATER Rebuild 94 Party Barge 24' 115 merc 22mph OP KS Truman Lake

curtiscapk Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 01/30/2013 Location: OP KS \Truman Status: Offline Points: 982	Post Options Post Reply Quote curtiscapk Report Post Thanks(0) Quote Reply Posted: 11/14/2018 at 9:38pm
	Never mind helps to look up!
	Craig n Paula THE FLOATER Rebuild 94 Party Barge 24' 115 merc 22mph OP KS Truman Lake

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 02/19/2019 at 4:11pm
	It has finally warmed up around here long enough to get some initial cutting done. After removing some of the factory brackets, we laid out lines every 10 degrees to measure back from to get our cut lines. Then shot a line laser from the side to make sure there were no glaring errors. Time to start cutting. Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Also mostly finished the fuel tank design: Untitled by scott011422, on Flickr

curtiscapk Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 01/30/2013 Location: OP KS \Truman Status: Offline Points: 982	Post Options Post Reply Quote curtiscapk Report Post Thanks(0) Quote Reply Posted: 02/21/2019 at 9:07pm
	Nice!
	Craig n Paula THE FLOATER Rebuild 94 Party Barge 24' 115 merc 22mph OP KS Truman Lake

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 03/25/2019 at 3:35pm
	So it turns out they don't make marine rated pre-bent 1.5 fuel hose, So we had to flip the tank around and fill it directly. Other than that, things are moving along. Weather is warming up and making progress: Cutting out Transom Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Bottom of Fuel Tank Frame: Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 04/22/2019 at 1:44pm
	So the big weekend was at hand. We were able to install the fuel tank and attach the transom. Were able to get all the main inside mig welds in while we had access to a spool gun. Welds were not all fantastic due to space constraints. Added in some extra gussets because we could and still have to TIG weld the entire outside. Don't think its going anywhere. Also ended up back filling the fuel frame with 6# closed cell foam which will give the tank and toon some extra support. Also started fabbing the panel that all the hoses and filling will be done thru. Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 04/22/2019 at 1:50pm
	Wrong Picture Untitled by scott011422, on Flickr

curtiscapk Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 01/30/2013 Location: OP KS \Truman Status: Offline Points: 982	Post Options Post Reply Quote curtiscapk Report Post Thanks(0) Quote Reply Posted: 04/22/2019 at 7:15pm
	wow amazing work!
	Craig n Paula THE FLOATER Rebuild 94 Party Barge 24' 115 merc 22mph OP KS Truman Lake

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 04/26/2019 at 2:31pm
	Fuel Panel Mount done Untitled by scott011422, on Flickr

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 05/03/2019 at 6:04pm
	Untitled by scott011422, on Flickr

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 05/29/2019 at 12:00pm
	Getting really close to getting the boat out on the water. I unfortunately didn't think to get any pics of the mounting process. We ended up taking the aluminum mount frame back off the toon and clamping that to the boat. Then we drilled all the holes in the boat using the mounting frame as a drilling jig. Worked Great! We also had to pull the fuel level sensor, in my haste, i forgot that the RTV i had at home wasn't fuel rated. so replaced that and sealed up the access door with some 4200. Untitled by scott011422, on Flickr Mounting Frame Work: Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Time to start sealing it up Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr In place on the Boat Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Also, I found this NOCO 8D Marine battery box to tidy everything up. Has enough room for 2 group 27 battery trays, distribution blocks, breakers and battery tender. Untitled by scott011422, on Flickr

curtiscapk Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 01/30/2013 Location: OP KS \Truman Status: Offline Points: 982	Post Options Post Reply Quote curtiscapk Report Post Thanks(0) Quote Reply Posted: 05/29/2019 at 3:59pm
	freaking awesome job!!!!!!!!!!!
	Craig n Paula THE FLOATER Rebuild 94 Party Barge 24' 115 merc 22mph OP KS Truman Lake

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 06/05/2019 at 5:01pm
	Have the toon pretty much done now. Access ports are complete. The fuel panel is done and sealed. All the wires are ran to the Battery box. Should be mounting the outboard this weekend. Untitled by scott011422, on Flickr Edited by Scott011422 - 06/11/2019 at 1:36pm

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 06/10/2019 at 5:05pm
	Time to finish this project up! Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr Time to see how she floats! Untitled by scott011422, on Flickr Untitled by scott011422, on Flickr About 7" higher! Edited by Scott011422 - 06/11/2019 at 1:36pm

Barnmb7117 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 09/11/2012 Location: Chicago,IL Status: Offline Points: 504	Post Options Post Reply Quote Barnmb7117 Report Post Thanks(0) Quote Reply Posted: 06/15/2019 at 1:02pm
	Wow. It came out really nice. How does it run?
	Mike 1993 Tracker fishing barge 21 2015 Evinrude pontoon series 90 hp Summer - On the wolf River Weyauwega, WI Winter- Chicago, IL

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 06/16/2019 at 10:39pm
	Unfortunately, we couldn't really test it much. We ended the year in 2018 with an overheat we thought was due to excessive seaweed fowling. That ended up not being the case as the outboard overheated 30 seconds after going full throttle all morning. So we ordered all the components for the thermostat and poppet valve. They both looked to be original. Water pump is new and looks great.

Scott011422 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04/23/2018 Location: Sycamore Status: Offline Points: 14	Post Options Post Reply Quote Scott011422 Report Post Thanks(0) Quote Reply Posted: 02/07/2020 at 7:14pm
	So new year, New projects. We did end up getting the engine all worked out. Stupid Poppet valve. Boat sits much higher and carries people soooo much better! But the third toon killed my speed. Now I cant even get on plane with 6 people on the boat. The 75 just isn't going to cut it any longer. Ended up at roughly 52% slip on a 14x13 3 bladed prop at 5k rpm. I did order a 14x11 to get the rpm's up higher, which leads us to this years project. We found a great deal on a 2008 Optimax 150. Bigger motor, Bigger prop, Should be able to get on plane now. So to the point of this posting, I feel the 75 was mounted a little low. I mounted the cavitation plate even with the bottom of the center tube with the boat and motor level. As you can see from the pic, It ended up being low. MY question is, When I mount the 150, being they are both 20" outboards, Can I just automatically mount it one hole higher? Or is the extra speed going to play that large of a role on my outboard height?? Thanks for the help guys Untitled by scott011422, on Flickr

River-Dave Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 08/24/2020 Location: Winfield Mo Status: Offline Points: 2	Post Options Post Reply Quote River-Dave Report Post Thanks(0) Quote Reply Posted: 08/28/2020 at 11:11pm
	did you get the 150 and how is it as far as the height you mounted it? I have a xr6 150 and I’m putting it on a 20 footer. Also was thinking about getting a hydraulic jack plate so I could raise or lower it.