Mounting 20-inch-shaft Engine on 13-foot with Notched Transom

  ContinuousWave
  Whaler
  Moderated Discussion Areas
  ContinuousWave: Whaler Repairs/Mods
  Mounting 20-inch-shaft Engine on 13-foot with Notched Transom

search | FAQ | profile | register | author help

Author Topic:   Mounting 20-inch-shaft Engine on 13-foot with Notched Transom

boatdryver posted 01-15-2014 03:09 PM ET (US)
[Seeks] an off the shelf bracket or simple fixed jack plate to [permit mounting of a 20-inch-shaft outboard engine on the transom of a 13-foot Boston Whaler boat with a 15-inch notched transom.] One shop I talked to thinks a custom aluminum fabricator will be required. My 13-foot Boston Whaler boat is so old there are no visible markings. It is pre-smirk with a blue interior. The outboard engine is a new E-TEC 30-HP, and the 20-inch shaft is required to get a model with electric start and tilt. Thanks, JimL
Tom W Clark posted 01-15-2014 03:24 PM ET (US)
Jim -- There are a number of adaptors out there, though not all of then provide enough lift. The T-H Marine Mini-Jacker, for example, is a nice piece of hardware but only provides 3" of lift and you need every bit of 5" or VERTICAL gain.
The transom on a 13' Whaler slopes back quite a bit so the transom needs to extended a lot more than just 5" if you want to gain 5" of height.
The best of the adaptors out there is probably the KentFabrications' Transadaptor13:
http://www.kentfabrications.com/TransumAdaptor.html
(Apparently his welding is better than his spelling)
Even with the Transadaptor, I'd mount the E-TEC 30 up off of it a hole or two.
Tom W Clark posted 01-15-2014 03:28 PM ET (US)
The Transadaptor13 also has the benefit of fully blocking the transom notch and reducing the amount of water slopping over the transom. No off-the-shelf jack plate will do that.
cc378 posted 01-18-2014 08:18 AM ET (US)
I used the Transdaptor and love it. I have it installed on two 13' whalers and have good performance on both. One has a Honda 25 and the other has a Yamaha 2 stroke 25.
cc378 posted 01-18-2014 08:20 AM ET (US)
Updated link to transdaptor http://www.kentfabrications.com/TransumAdaptor.html
thegage posted 01-18-2014 10:04 AM ET (US)
Another nod to the Transdaptor. Expensive, but it does the job very well. If you get one, as Tom notes just make sure the engine mounting holes are drilled so that you can raise the engine high enough to get the best performance. The Transdaptor is actually slightly dished, so if the engine is all the way down on the transom it is way too low--that was the case with my E-TEC 30 with manual tilt. With the E-TEC you're going to want to be able to experiment with raising it all the way up in order to get the best performance.
John K.
contender posted 01-20-2014 08:50 PM ET (US)
It comes down to how you want your whaler to look, The plates in the previous threads can be used, but then (to me) looks like crap with holes in the transom. I would have the notch filled in using fiberglass and make it a full transom and make it look factory. When it comes down to it the costs are going to be about the same, but maybe a little more time in doing it correctly....to each his own

Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.

Author	Topic: Mounting 20-inch-shaft Engine on 13-foot with Notched Transom
boatdryver	posted 01-15-2014 03:09 PM ET (US) [Seeks] an off the shelf bracket or simple fixed jack plate to [permit mounting of a 20-inch-shaft outboard engine on the transom of a 13-foot Boston Whaler boat with a 15-inch notched transom.] One shop I talked to thinks a custom aluminum fabricator will be required. My 13-foot Boston Whaler boat is so old there are no visible markings. It is pre-smirk with a blue interior. The outboard engine is a new E-TEC 30-HP, and the 20-inch shaft is required to get a model with electric start and tilt. Thanks, JimL
Tom W Clark	posted 01-15-2014 03:24 PM ET (US) Jim -- There are a number of adaptors out there, though not all of then provide enough lift. The T-H Marine Mini-Jacker, for example, is a nice piece of hardware but only provides 3" of lift and you need every bit of 5" or VERTICAL gain. The transom on a 13' Whaler slopes back quite a bit so the transom needs to extended a lot more than just 5" if you want to gain 5" of height. The best of the adaptors out there is probably the KentFabrications' Transadaptor13: http://www.kentfabrications.com/TransumAdaptor.html (Apparently his welding is better than his spelling) Even with the Transadaptor, I'd mount the E-TEC 30 up off of it a hole or two.
Tom W Clark	posted 01-15-2014 03:28 PM ET (US) The Transadaptor13 also has the benefit of fully blocking the transom notch and reducing the amount of water slopping over the transom. No off-the-shelf jack plate will do that.
cc378	posted 01-18-2014 08:18 AM ET (US) I used the Transdaptor and love it. I have it installed on two 13' whalers and have good performance on both. One has a Honda 25 and the other has a Yamaha 2 stroke 25.
cc378	posted 01-18-2014 08:20 AM ET (US) Updated link to transdaptor http://www.kentfabrications.com/TransumAdaptor.html
thegage	posted 01-18-2014 10:04 AM ET (US) Another nod to the Transdaptor. Expensive, but it does the job very well. If you get one, as Tom notes just make sure the engine mounting holes are drilled so that you can raise the engine high enough to get the best performance. The Transdaptor is actually slightly dished, so if the engine is all the way down on the transom it is way too low--that was the case with my E-TEC 30 with manual tilt. With the E-TEC you're going to want to be able to experiment with raising it all the way up in order to get the best performance. John K.
contender	posted 01-20-2014 08:50 PM ET (US) It comes down to how you want your whaler to look, The plates in the previous threads can be used, but then (to me) looks like crap with holes in the transom. I would have the notch filled in using fiberglass and make it a full transom and make it look factory. When it comes down to it the costs are going to be about the same, but maybe a little more time in doing it correctly....to each his own