Transom extender on a power sailer

[TortugasRoyal]

Starting a new thread set to the general interest category so I can capture the expertise of all forum members. Not just Mac26x. Could use some help creating my new transom extender for my Mac 26x sailboat.

Here's the original thread: http://forums.macgregor.sailboatowners.com/showthread.php?t=149685

I want to eliminate all the engine, rudder, and rudder connector congestion at the rear of the boat. Move all of that back to the rear of an extender with a platform.

I have read propaganda touting the benefits of extenders such as faster on plane, up to 25% better fuel economy, and 2-3 mph WOT speed increase. Is it true?

The platform welded, permanent top will be lower than the boat deck in rear. Over that a removable deck installed flush with the boat deck. In that space, the twin rudder connecting hardware and all wiring and steering cable will be located. The platform will be equal to the boat's stern opening 48", or should I go full stern width?

Should the extender be flotation type, perhaps 24" long? What about following seas?

The transom will be reinforced with aluminum.

http://s2.beta.photobucket.com/user/Chamelea26X/library/Mods%20-%20Transom

How shallow can one expect to run the outboard cavitation plate with a 24" extender? Setback and depth discussed here. 12:1 rule is it real?

http://www.ifish.net/board/showthread.php?t=288623

Mac26x boats have a bowup problem when trying to achieve plane. My nissan NS50d transom thrust rod is at the last hole closest to the stern/boat. Some owners have installed wedges to angle to prop more inward toward the bottom of the boat. Should I make the new outboard mounting plate more angled than the OEM stern? Or will the lever arm created by the extender be enough to correct this?

What kind of propeller pitch change will I have to do with the prop running in cleaner water? 10x10pitch great slow speed control but can over revs WOT and slow to plane at 15 mph at 5500rpm. Optimum for a nissan 50hp is suppost to be 11.5x11pitch. Got a 11.5x12pitch I have not tried yet on stock boat.

Think it is OK to mount my magma charcoal grill on a pedastal back there?

Suggestions regarding built in ladder design please.

thanx for your time!

 

[MrBill_FLL]

you are underpowered with a 50hp. if your goal is to plane better/faster you need a bigger engine. (70hp would be about right, IMHO). if you want a swim platform, then this may work for you. -notice the test case had 2) 200hp engines. -not underpowered. these brackets work great on open fish/gofast. not so much with semi displacement hulls. the engine shim might be the best idea here...

 

[TortugasRoyal]

you are underpowered with a 50hp. if your goal is to plane better/faster you need a bigger engine. (70hp would be about right, IMHO). if you want a swim platform, then this may work for you. -notice the test case had 2) 200hp engines. -not underpowered. these brackets work great on open fish/gofast. not so much with semi displacement hulls. the engine shim might be the best idea here...

Primary goal is to unclutter the stern, move the engine and rudders back, greatly improve the ergonomics. and have a swim platform. Could someday install a larger engine......

 

[mklein@iowatelecom.net]

Don't let this thread die! I am greatly interested in the results. Please keep posting information on the progress. I may have to do something like this someday! Thanks, Mark

 

[MrBill_FLL]

fwiw, I saw a picture of a 'swim platform' on an X. it was actually over the rudder controls, (arms) in front of the engine. wooden, slat type, raised up maybe 2" over the controls. -probably on macgregor-sailors.
very elegant, and nice design.... on this idea, I still worry about the transom connection to the sides. not the transom itself.


ps: link for brackets, and jack plates http://www.bobsmachine.com/

-also not a fan of the 'T' type boarding swim ladder... has to be stored someplace. prefer the nesting type. ie: http://www.garelick.com/Under-Platform-Sliding-Ladder

 

[vizwhiz]

I checked into this once, and the Armstrong guy I contacted was very interested in working with X/M owners to develop the right type of platform/extender, especially knowing the quantity of boats out there, and the potential for truly improving the boat performance, particularly ease of boarding the boat. Their platforms have the hideaway swim ladders available as an option already. They are probably the most worthy builder...and were interested. Will gladly pass along my contact info if you are interested.

 

[TortugasRoyal]

I shopped, via email, the vendors making units for $1500 or less. Only one expressed interest in making this. And he wanted drawings to fabricate from. If I had that, I would have it made locally. So this project is not going to happen. Going with plan B. Install SeaStar hydraulic outboard steering and use two panther 55-2750 drive brackets to link to each rudder. That will get most all the clutter out of the way.......

 

[TortugasRoyal]

bought an 18" mount
http://www.ebay.com/itm/AFFORDABLE-OUTBOARD-ENGINE-MOTOR-BRACKETS-SINGLE-TWIN-CUSTOM-MADE-/221249586028?pt=Boat_Parts_Accessories_Gear&hash=item338380c36c&vxp=mtr
and installed hydraulic baystar steering also.
Upgraded auto pilot to hydralic pump steer as well.
the mount can hold a 14 gallon fuel bladder.
flipped rudder crossbar 180 degrees to reduce remaining clutter.
still have to install raymarine rudder position sensor for autopilot.
resuseing rudder to outboard link.

 

[MrBill_FLL]

have you done a sea trail yet? how did it work?

 

[TortugasRoyal]

No test on water yet.