Transom Capacity

[MN Sun]

Hey Guys-

Been a while since I have had something to post but now I have a question for which I can't seem to find an answer

I have a 1988 Alumacraft Competitor CS rated for 90HP. It has a 1988 Mercury 80HP ELPTO weighing 268lbs dry. I have an opportunity to purchase a 1997 Honda 90HP. Thing is, the Honda weighs 358lbs dry. I know this is not an issue for the overall weight capacity of the boat, but is 90 extra pounds on the transom acceptable?

Any help/insight you guys have is much appreciated!

Happy boating!

-MN

 

[joelybob]

Re: Transom Capacity

I would contact Alumacraft and see what they think.

 

[64osby]

Re: Transom Capacity

The boat is rated for 90 hp. The transom if in good shape should handle it with no problem. The issue is you are using an extra 90 pounds of the capacity of the boat.

Do you know what the boat weight capacity is? Installing the motor may require moving other weight forward to balance the boat.

Another consideration is do you have a kicker motor?

 

[Texasmark]

Re: Transom Capacity

BIA ratings have to do with the boat's dimensions and safety characteristics. Transom toughness isn't one of them. I have only seen one boat with the transom ripped out of it and it was a homemade 14' wooden boat with the old "Fat 60" rude. First time out, in front of all his buddies on the pier he goosed it and didn't get 20 ft. Engine submerged (in salt water) and only thing holding on to it were the cables.

Most transoms are at least 1 1/2" thick and have a knee in the center. I've seen a pair of 90 hp towers on such. OEMs usually over design their equipment so that no big surprise comes up later requiring a recall and a lot of expense and adverse publicity. Personally wouldn't worry about it but calling Alumacraft sounds like a good idea.

My 2c,
Mark

 

[greenbush future]

Re: Transom Capacity

BIA ratings have to do with the boat's dimensions and safety characteristics. Transom toughness isn't one of them. I have only seen one boat with the transom ripped out of it and it was a homemade 14' wooden boat with the old "Fat 60" rude. First time out, in front of all his buddies on the pier he goosed it and didn't get 20 ft. Engine submerged (in salt water) and only thing holding on to it were the cables.

Most transoms are at least 1 1/2" thick and have a knee in the center. I've seen a pair of 90 hp towers on such. OEMs usually over design their equipment so that no big surprise comes up later requiring a recall and a lot of expense and adverse publicity. Personally wouldn't worry about it but calling Alumacraft sounds like a good idea.

My 2c,
Mark

I watched an older wood Thompson with a tower of power, just about tear the entire back off that boat. It separated 3/4 of the transom from the back of the boat, just bouncing off some 4 footers, trying to make the weigh in for a salmon tourney on Lake Huron. We didn't take her back out the second day of the tourney, scrapped the hull after that.

 

[snowman48047]

Re: Transom Capacity

I emailed Lund about this exact topic. I was questioning the weight difference between a 2 stroke 120hp Merc and a 4 stroke 115 Yam. The answer I got was as long as you don't exceed the HP rating and the total capacity of motor, passengers, gear, etc... then you are good to go.

Send them an email and I'm sure they will say the same thing.

 

[WIMUSKY]

Re: Transom Capacity

If Alumacraft says the extra weight will be fine on the transom, you'll probably be a little tail heavy with the extra 90#. You may need to move weight forward, if possible. Otherwise, your hole shot may be affected and you may not be able to trim it out as much. I'm assuming it's a 16'. My 60hp 4 stroke weighs the same as that 90. And 20# more than a 90 of the same year as my 60 and boat. Mine's rated for 90 too.

You see newer motors on older boats all the time. And yours isn't really that old....

 

[BobGinCO]

Re: Transom Capacity

That's 90 pounds of beer you can't bring along...

 

[MN Sun]

Re: Transom Capacity

That's 90 pounds of beer you can't bring along...

That's exactly what I told the Admiral (wife) the only dowside was!

But seriously, thanks for all the great advice and insight, guys! I will contact Alumacraft just to be sure, but I think I'm gonna go for it.

This forum truly rocks, I never cease to find great information from everyone involved!

-MN

 

[WIMUSKY]

Re: Transom Capacity

Actually, you'll probably need it to put in the bow for better balance....lol

 

[GA_Boater]

Re: Transom Capacity

Actually, you'll probably need it to put in the bow for better balance....lol

But in the end 90 pounds of beer end up as only about 5 pounds of empties and a higher lake. Bring a designated drive along.

 

[MN Sun]

Re: Transom Capacity

Actually, you'll probably need it to put in the bow for better balance....lol

See! This is why I love this forum. Common sense advice! :bounce:

 

[saumon]

Re: Transom Capacity

But in the end 90 pounds of beer end up as only about 5 pounds of empties and a higher lake. Bring a designated drive along.

I always wondered why lakes level vary so much. Now I know.