Raising the Transom?!

[Seasons Recreational]

Hi all, newbie here! I just bought my first boat, a 1960 Sea King 14'. I also purchased a separate outboard, a 2004 Johnson 9.9 4-stroke. I think that the shaft length might be a tad long for the transom. It's about 3-4" longer than the transom is high. Will this be ok to run on this boat?

I am also considering replacing the transom plywood and there is an opportunity to raise the top of the transom (the existing transom drops in the center). I could gain about 2-3" of height in the transom if I do this, raising the motor and prop almost to where it needs to be. Is this advisable?

Attached photo showing the dropped transom in the center.

Thank you!

 

[briangcc]

Need a side shot so we can see the transom and the outboard. Generally, if the anti-cav plate is in line with the keel of the boat you should be fine.

 

[Seasons Recreational]

Need a side shot so we can see the transom and the outboard. Generally, if the anti-cav plate is in line with the keel of the boat you should be fine.

Thanks Brian,

Here are some better photos with dimensions. It looks like I am a bit low. The anti-cav plate is about 5" below the bottom of the boat and about 3" below the rib (as shown in the photo).

Any suggestion on how much to raise the transom? I am replacing it this weekend...if I raise it to flush, I'll get another 2" higher approx. if I want to pick up the whole 5" I'll have to raise it about 3" above the top of the boat. Not excited to do that... Thank you!

 

[flashback]

You got the idea vent plate on engine needs to be damn close to the bottom of hull. Obviously we don't know what that is but your red sharpie markers will tell you...

 

[Seasons Recreational]

Thanks Brian,

Here are some better photos with dimensions. It looks like I am a bit low. The anti-cav plate is about 5" below the bottom of the boat and about 3" below the rib (as shown in the photo).

Any suggestion on how much to raise the transom? I am replacing it this weekend...if I raise it to flush, I'll get another 2" higher approx. if I want to pick up the whole 5" I'll have to raise it about 3" above the top of the boat. Not excited to do that... Thank you!

Thanks

You got the idea vent plate on engine needs to be damn close to the bottom of hull. Obviously we don't know what that is but your red sharpie markers will tell you...

Thanks Flashback. I think I got it now. This is a helpful photo I found on the internet. I didn't realize the height is critical! Looks like we're going up 5" +/-.

 

[flashback]

Yep, raise transom or shorten the leg.

 

[Seasons Recreational]

Yep, raise transom or shorten the leg.

Cheaper to raise the transom I would suspect.

 

[flashback]

I would think so since you're transom is already in question..

 

[Texasmark]

You have a 20" skeg engine on a 15" transom. 5" is your number. What you have will run but performance will be hindered by too much skeg in the water producing unnecessary drag. Also that extra 5" will put you in the mud, or catch on logs, or moss or lilly pads etc.

Make a pattern of your current transom and add 5" to the clamp bracket area......looking at your 3rd picture that should make the top straight across without the dip in the center.

 

[Seasons Recreational]

You have a 20" skeg engine on a 15" transom. 5" is your number. What you have will run but performance will be hindered by too much skeg in the water producing unnecessary drag. Also that extra 5" will put you in the mud, or catch on logs, or moss or lilly pads etc.

Make a pattern of your current transom and add 5" to the clamp bracket area......looking at your 3rd picture that should make the top straight across without the dip in the center.

Thanks Texasmark. Is there any downside to raising the engine so much?

 

[airshot]

That 9.8 is minimal hp for that boat, a 25 hp would be much better. You might consider getting a larger motor with the right length shaft before raising the transom. Unless you have a specific reason for a small motor, that 9.9 might be dissapointing... Just a thought !!!

 

[Seasons Recreational]

That 9.8 is minimal hp for that boat, a 25 hp would be much better. You might consider getting a larger motor with the right length shaft before raising the transom. Unless you have a specific reason for a small motor, that 9.9 might be dissapointing... Just a thought !!!

I was waiting for somebody to say this. It’s called poor dad gets a project, but no budget

 

[brodmann]

Yep, we've all been there! If it's your first boat, it will be amazing just being out on the water. Enjoy what you have, and one day when you have something bigger and better, you'll look back at this boat/motor set up and laugh at how much you enjoyed that little boat with the little motor! Have fun with it!

 

[Seasons Recreational]

Yep, we've all been there! If it's your first boat, it will be amazing just being out on the water. Enjoy what you have, and one day when you have something bigger and better, you'll look back at this boat/motor set up and laugh at how much you enjoyed that little boat with the little motor! Have fun with it!

I think I’ll have your entire message engraved on the dash. Set me at peace Thanks Brodmann

 

[Texasmark]

Thanks Texasmark. Is there any downside to raising the engine so much?

Well if you had a 15" stock OEM skeg on your engine you wouldn't need to jack ut up 5" to accommodate your 20" OEM skeg.
Since you said you are doing the whole transom, it will all be one piece and you won't have to worry about the strength of a joint there as you would if you were just capping your existing one.

Go find you a dealer or boat yard, marina, and look at transoms on boats similar to yours. Some include aluminum sheets where the engine clamps and on the reverse side so that the engine mounting doesn't tear up the wood. If you are really worried, make a U shaped cap out of one piece of metal that starts on the inside of the boat, bends over the top and goes down the back, covering where the engine clamps......sheet metal shops that make air conditioning custom ductwork have the proper bending machines that can do that for you.