Stronger Transom Questions...Please Help

AK_Fish

Cadet
Joined
Apr 7, 2010
Messages
11
Hello-

I am new to this amazing website and I have been doing a lot of reading about how to rebuild your transom and how to replace it, but what I am trying to figure out...is if there is any way of just making one stronger without ripping everything apart and starting from scratch. I have a 16' flat bottom Lowe and currently it has a 25 hp mercury 2 stroke and I am about to put on a 40 hp evinrude 2 stroke (70 lbs heavier than the one currently on there) The boat is rated for a 40hp, but because I am putting a bigger motor on, and the boat is an older rivited aluminum, I just want to be sure that the transom is strong enough to hold the motor...Because of course no one wants to be cruising down the river and have the motor rip off the boat, taking the transom and half your boat with it:( Any help or experience / advice that you guys have would be greatly appreciated because I know there are some incredibly smart and experienced experts in the boating field here on this website. Again, this is only my first ever post so please bare with me if I dont know everything yet...:p Also, I have done my research and read a ton about the subject here and over the internet but again, it was mostly things regarding replacing the entire thing. Also I have attached 2 pictures that show the transom so you experts can get an idea of what it looks like and how its designed. Thanks a lot guys...I hope to get some good advice soon!!!!!

Thank You...Adam
 

Attachments

  • IMG00047-20090525-1936 (19).jpg
    IMG00047-20090525-1936 (19).jpg
    136.7 KB · Views: 0
  • IMG00049-20090525-1936.jpg
    IMG00049-20090525-1936.jpg
    142.2 KB · Views: 0

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,065
Re: Stronger Transom Questions...Please Help

Welcome to iboats.

Lets determine if you need extra strength. Place your current 25 into a fully tilted and locked position....... using your body weight push down on the prop....... if the transom moves (just the transom) more that 1/4" it is time to rebuild it. If it is solid..... you will be fine with the extra weight.

If you hung a plate of solid steel on the transom for "strength" the pressure still ends up on the transom. I have seen some real creative attempted transom repairs but it is all plain old physics. The only other way to add strength to a transom is with an additional knee brace
 

AK_Fish

Cadet
Joined
Apr 7, 2010
Messages
11
Re: Stronger Transom Questions...Please Help

Thanks for the welcome...You mean place the motor up out of the water like when your traveling the boat on a trailer right? And what is a knee brace? Is there somewhere to buy one or do you just fabricate it? Also you say to watch the transom and see if only the transom moves more than 1/4". Should I be watching anywhere else to see if other stuff is moving as well. Or only watch where just below where the motor is mounted and below. Thanks a lot I really appreciate it.

Thank You...Adam
 

Gary H NC

Fleet Admiral
Joined
Dec 1, 2005
Messages
8,972
Re: Stronger Transom Questions...Please Help

Welcome AK,

What you are looking for is flex in the transom.
If it is solid with very little flex with the 25 then the 40 should be fine.

Yes,Bob was talking about having the motor up in the trailer position and seeing if when you push down on the motor does the transom give.
 

tx1961whaler

Vice Admiral
Joined
May 31, 2008
Messages
5,197
Re: Stronger Transom Questions...Please Help

If the boat is rated for 40HP and the transom passes the deflection test above, then you're good to go. The extra weight of the bigger outboard is largely irrelevant. It's the extra torque put on the transom by the higher prop thrust that is the concern.
 

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
Re: Stronger Transom Questions...Please Help

Welcome to iboats!:cool:

The boat looks to be in good general condition, so I don't think you'll have any problems, since you are staying within the rated capacity (alleluia!;)) Just check the existing structure for cracks, missing or loose rivets.

Again, this is only my first ever post so please bare with me if I dont know everything yet...:p
Sorry, this is a family-friendly site. I'm keeping my clothes ON, thank you very much! :eek:

(Sorry, I crack myself up sometimes.:redface:)
 

AK_Fish

Cadet
Joined
Apr 7, 2010
Messages
11
Re: Stronger Transom Questions...Please Help

Great Thank you guys so much. I will try tomorrow when I ge back over to to the boat! I really apreciate the expertise!!! One more question...does anyone know where I can get specs on a specific motor. I am trying to find the shaft length of a 1995 evinrude mode E40 TLEOD. But I cant find it. Thanks again guys...What a blessing this is to have such a wealth of knowledge all in one place.


Adam
 

AK_Fish

Cadet
Joined
Apr 7, 2010
Messages
11
Re: Stronger Transom Questions...Please Help

Any other ideas of how to strengthen a transom and / or surrounding areas???
 
Top