CONTINUOUSWAVE

I am refurbishing a 13-footer that has the original notched transom for a 15-inch-shaft engine. I will be putting on a new Yamaha F25 which weighs 126-lbs.

Shoud the transom be kept at original height?

Should a Kent Fab insert be used to raise the height for a 20-inch-shaft ehgine?

If the new engine has a 20-inch-shaft height, the engine won't work well if mounted directly to a 15-inch transom.

To get a better answer, tell us the shaft length of the new engine.

See:

CETACEA Page 56.

--and--

A 20-inch-shaft Engine on a Classic 13
http://continuouswave.com/forum/viewtopic.php?t=64

Here is another choice.

https://www.nausetmarine.com/shop/boston-whaler-transom-riser/

I copied Don Jahncke’s transom raise job on my 13-footer. It takes more time and skill than one would think.

Makes the Kent and Nauset parts look like a good choice.

Con

If you must install a 20" shaft, consider using this. Many owners have installed them.

https://thmarinesupplies.com/products/cmc-static-jack-plate-5-inch-vertical-extension

I can buy either a 15-inch or 20-inch shaft engine.

Are there are any advantages to spending money to raise the transom?

Should I just keep the boat as-is with 15-inch transom?

I raised mine because I was going to put a power tilt and trim motor on the boat. Most of those are 20”.

If you can buy a 15” motor I would not raise the transom. Just come off plan slower so as not to get pooped by the wake.

Con

Agree with Con.

Don't go to the hassle of band-aiding the transom due to selecting the wrong shaft engine.

I went with the Koski mahogany transom extension http://www.koskiboatworks.com/custom-whaler-accessories.html

Haven't put it on yet, I've grossly underestimated the amount of time to do the repairs I need to do. I thought it looked the best, helped prevent wake coming over, weighed the least, and theoretically you can go back to the original notch if you wanted.

cjohnsen89 wrote:Are there are any advantages to spending money to raise the transom?

I really do not know how to answer the actual question asked regarding what is the advantage of spending money, except in a general answer that spending money is usually good if it gets something you need (or think you need) or makes you happy, and it often allows you to avoid doing a lot of lousy work that you do not enjoy.

Instead I will answer as if you asked this question: Is there an advantage to a higher transom?

You can make a very reasonable assumption that there MUST be an advantage a higher transom just on the basis that Boston Whaler made the transom higher in later models of the 13-footer.

I can think of two advantages: a higher transom will create higher freeboard at the stern. A higher transom will also be stronger than the notched transom.

Simple...if you want PTnT, you will need to put a 20" engine on it, you chose what method you want. I personally think a standard manual jackplate is the most efficient and strongest and the setback gives you better performance. You can usually bolt these to the original holes, thus not having to drill new ones. If you do not want PTnT, buy a 15" engine and call it a day...a cheaper day.