Why Does The Outdrive Feel Solid When The Transom Is Rotted?

[DavidW2009]

I recently bought a good trailer. A 1987 Baretta Super Sport (16') came with it. From the inside, the transom is obviously rotted and soft spots in the floor.

From the outside, the transom looks great. No stress cracks anywhere.

With the drive in up position, I can lift the back end of the boat by the skeg and see no deflection in the transom. I read this is a way to check a transom on an I/O.

How come it feels so solid when it's so rotted inside? What is actually supporting the outdrive?

Before I start any work on this boat, I'd like to lake test it next month. But I need to determine if it's seaworthy (lake-worthy).

(I hope I'm posting this in the right place. Move it if necessary)

 

[199q]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

core sample is the best way to tell. a few shallow holes through the wood, catch the shavings.

if they are wet you have rot, if they are dry you are good to go!


I would check it out before the lake test just to be safe. also ensure you have a paddle, long ropes, bailing bucket and a charged battery with a good bildge pump.

those items are only needed if things hit the fan, but if you have them and need them you will be a happy happy person. if you have ever tried to paddle your boat with your hands, you will carry good ones after that!

boats dont sink because something happened. boats sink because people are unprepared and something happens. i think you would be fine though, just be cautious!

 

[DavidW2009]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

I removed the power steering pump from the transom today and set it to one side as part of inspecting the lake-worthiness of the boat.

I wasn't expecting to see wood infestation in a transom. Either termites or some wood borer got to it in the recent past. In the bilge, under the P/S pump, was a pile of sawdust.

I wonder if the pest control companies do boats? LOL.

 

[zach103]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

i don't know much about the i/o's but i know the outdrive is connected to the engine.. so maybe thats why you don't see anything moving.. that and im sure the fiberglass on the outside is a good thickness

 

[DavidW2009]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

The engine has two motor mounts and the bell housing has two mounts. I'm thinking that most of the weight and forces of the outdrive are transferred to these four mounts. The mounts are sturdy and appear to be in good conditon, as is the wood that is glassed over.

So, I may be safe in lake testing it and assessing it mechanically to see if it's worth a new transom, stringers and deck.

 

[zach103]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

before you go out make sure your bilge pump is working and take someone with you.. have somone on shore.. just incase samething goes wrong you can paddle back right onto the trailer.. we don't need you and the boat sinking

 

[DavidW2009]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

Yes, I agree with your last comments.

I plan on putting it in the water and leaving it tied to the dock, engine running, and check for any leaks at all. If I see a leak around the keyhole area, the boat goes back on the trailer.

 

[zach103]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

Ya thats deff a good idea.. . When do you plan on taking it out?

and you shouldn't have to worry about the whole sea worthy thing... if your worried.. take the hose out and fill the boat up a little and see if anything leaks out.. the transom should be fine especially if your just gunna sit at the dock.

 

[DavidW2009]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

I plan on taking it out in a few weeks. I'm waiting for the weather to get past the freeze point so the boat can be summerised.

I don't want to risk damaging anything by filling the boat inside with water.

If it doesn't leak at the dock, I'll take it out. There's a small lake near here that's shallow. It has whole inlets that are only 3-5 feet deep, mud bottoms. I'll test it there.

Thanks for you input.

 

[proshadetree]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

Most transoms are only rotted on the lower section. My bayliner was solid 1/4 way up it was only rotted at the lower end. I didnt do sample I set it in the water and my son said "water water water" He didnt see where it was pouring in at. I pulled the boat and saw water exiting the transom under the drive plate.
Im still glad I didnt do a sample I dont have a patch at the back of my boat. The only way I would have found mine was to drill below the outdrive. I couldnt get to it from the inside.

 

[Bondo]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

The engine has two motor mounts and the bell housing has two mounts. I'm thinking that most of the weight and forces of the outdrive are transferred to these four mounts. The mounts are sturdy and appear to be in good conditon,

Ayuh,... The Flex you can't find in the rotten transom is what Destroys the Coupler...
The outdrive should Not be pushing on the motor...

 

[DavidW2009]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

Bond-o,

Thanks for the feedback and understanding.

That puts things in a different light. The boat will not get lake tested until it's fixed. Or never, if it's parted out.

 

[Bondo]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

Ayuh,... That's why We're always harpin' about Alignment,+ Checking it...
That's usually the 1st fatality in a Rotten transom scenario... The Coupler...

You,... Jumpin' on the outdrive, in No way compares to the levered torque thrust applied to it under Launch...
Idle to WOT...

Good luck with it whatever you do,....

 

[199q]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

Another thing you may try is to back the boat into the water on the trailer. you can still lower the drive and start it as long as the out drive is in the water.

To be totally honest though, get a pair of muffs from walmart and you can test it in your back yard. you wont sink there!


If it is rotted though, it will leak. and if it is rotted bad the forces of driving around could crack your transom and sink you.

 

[tinkeringwackyone]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

my boat was taking on water but didn't know where. I back my boat in the water, but left it on the trailer. just Idle it wasn't doing anything, even in idle reverse nothing, but kicked up the throttle and the outdrive stressed the transom and broke the seal on the outdrive, was able to look under the bell housing and see the water coming in. This took all of 10 mins. hope this helps.

 

[DavidW2009]

Re: Why Does The Outdrive Feel Solid When The Transom Is Rotted?

After reading the comments on this thread and others, I took another look at the transom today to see if I could find the answer to the question.

I removed the doghouse, rear seats and a trim panel and gained access to the transom. With a sharp knife, I poked all around the drive on the inside.

I found the entire upper half of the transom to be sound. The upper mounting bolts were holding the outdrive solidly to the transom. There's enough load bearing strength to make the outdrive feel solid when lifted from the outside. The runners that support the motor mounts are solid, also. They look like they're completely encapsulated in thick layers of fiberglass and resin. (Too bad the stringers and the deck were not built like that)

The entire lower half of the transom was completely rotten. The boat is not sea worthy. It would probably leak like a sive. The knife blade went all the way thru.

The boat (according to the PO) has not been in the water since 2005. At that time the transom may have been okay because there are no stress cracks anywhere.

The boat sat uncovered under a tree for (5) years without being used. Methinks the major part of the rot damage took place since the last time it was in the water.

When I bought my Bayliner, the first thing I did was have a new carport installed just for the boat(s). Letting a boat set out in the open is inviting a shortened life-span of that boat. Imho, a cover is not enough to keep the sun and the elements from deteriorating the boat. Need a good sturdy carport or garage and a cover.

(Rant over.)