Transom Leak Help

[Sunken Ship]

2000 Larson 186Lxi w/ Volvo SX
Well I'm back after a few trouble-free seasons. There I was cruising along about 20mph minding my own business and suddenly we all lurch forward with the boat slowing rapidly. I looked back and saw the mud trail and immediately cut throttle and raised the outdrive. Straightened the prop out-it was bad-and finally took it for a drive today. Prop is fine, but she's leaking and I am having to run the bilge every ten minutes or so. Water is coming in at the bottom just under the inside of the boat under the outdrive mount plate (on the inside of the boat of course). Tried to take some photos of the location.

What do you guys think? Serious damage? Thanks for any help.

 

[GSPLures]

By the pictures looks like the transom is rotted. Possible that when you bottomed the out drive with a soft transom that the gimbal may have moved and broke the seal.

 

[Sunken Ship]

I can pretty much guarantee she broke from hitting bottom...not rot. The question is severity.

 

[Scott Danforth]

Its broken.... PERIOD

pull the drive, pull the motor and start finding what needs repair / replace.

Im with GPS.... Looks like rot

 

[Grub54891]

Yup. looks like typical rot issue. Do not use it till it's fixed correctly.

 

[GSPLures]

I can pretty much guarantee she broke from hitting bottom...not rot. The question is severity.

Below the transom plate looks like the glass is cracked and starting to delaminate. If it isn't leaking through a bellow chances are its leaking from the housing. If that is the case the motor needs to come out along with the everything off the back to replace the seal. Not sure about volvos but my mercruiser has a big rubber o ring to seal the housing.

 

[racerone]

Remove the drive ----Remove the motor.---Rebuild the transom.----Opportunity to make it stronger than when new.-----But inspect stringers under the floor as well before deciding on the transom makeover.

 

[jbcurt00]

I can pretty much guarantee she broke from hitting bottom...not rot. The question is severity.

I think most here will agree, the bottom strike flexed the transom, but the result was severe because the transom wasnt 100%. No matter, now its time to pull the drive and engine and assess actual damage.

Based on pix showing fiberglass delamination, its 50/50 at best the transom wont have to be replaced, at best 50/50. I'd bet a case of beer its more then 75% likely to need a new transom.

 

[Sunken Ship]

Thanks for the input guys. I agree hitting bottom flexed it too much resulting in a leak. Gonna see what a local shop says about it next week. Hoping the local boat shop has the tool to scan the transom and see if it is rotted. It appears water is coming in here (see arrow). The stringers are glass so they are not rotted. New transom...surprise woody with a project lol. If that transom is rotted I can't imagine it would not have ripped the outdrive completely off the boat.

 

[GSPLures]

The glass can still be solid for the stringers and the core rotted. Unless the glass is structural with a foam core.

Is it coming in from the keyhole or actually through the transom?

 

[hugh g]

Thanks for the input guys. I agree hitting bottom flexed it too much resulting in a leak. Gonna see what a local shop says about it next week. Hoping the local boat shop has the tool to scan the transom and see if it is rotted. It appears water is coming in here (see arrow). The stringers are glass so they are not rotted. New transom...surprise woody with a project lol. If that transom is rotted I can't imagine it would not have ripped the outdrive completely off the boat.

There's no special scan tool that I know of that can tell you whether or not the transom is rotted. All you need is a cordless drill & a drill bit. Drill a series of holes in the inside side of the transom starting from the bottom. Don't go thru the outer skin. If the wood is punky & wet then your transom is shot & they rot from the bottom up. From your pics it looks like the glass has delaminated. Not a good sign. Best of luck.

 

[JASinIL2006]

The glass can still be solid for the stringers and the core rotted. Unless the glass is structural with a foam core.

Is it coming in from the keyhole or actually through the transom?

A 2000 Larson would have structural fiberglass stringers and bulkheads - no wood. It's only too bad they continued to use wood in the transom.

 

[JASinIL2006]

Thanks for the input guys. I agree hitting bottom flexed it too much resulting in a leak. Gonna see what a local shop says about it next week. Hoping the local boat shop has the tool to scan the transom and see if it is rotted. It appears water is coming in here (see arrow). The stringers are glass so they are not rotted. New transom...surprise woody with a project lol. If that transom is rotted I can't imagine it would not have ripped the outdrive completely off the boat.

You easily could have a bottom strike that causes a leak to start without tearing the outdrive off the boat, if only the bottom part of the transom around the keyhole is rotted.

It's really easy to check the transom yourself without incurring any cost from a shop. (I also have never heard of a 'scan tool' to check the transom.) Just get a drill, a 1/4" bit, and put a piece of tape around the bit about 1.5" from the tip of the drill. Reaching into the back of the boat (on the inside) and drill some holes around the keyhole, being sure not to go deeper than the tape mark on the drill bit. If your shavings are light-colored and dry, you're in good shape. Just fill the holes with a good sealant (e.g., 3M 5200), get the transom seal fixed, and consider yourself lucky.

If the shavings are dark and/or wet, you have rot. It's really simple to check and with a 21year old boat, it's not a bad idea to know for sure you don't have a problem.

 

[kcassells]

Its a shame. No magic fix other than a new transom and probably all the stringers based on the pics you supplied.
If you are handy you have aproject guys here can walk you thu. If not then the local shop is going to bang you.
It is all doable.

 

[hugh g]

Now that the world has lost it's mind the cost of materials has skyrocketed. Another poster here recently got a shop quote of $8000 for a new transom, stringers & floor. Ouch.

 

[Sunken Ship]

Took it to the local boat shop and I did get SOME good news-transom is "solid". Bad news: motor is coming out and it will cost over a grand to fix.

 

[Grub54891]

Took it to the local boat shop and I did get SOME good news-transom is "solid". Bad news: motor is coming out and it will cost over a grand to fix.

So what it the problem?

 

[Sunken Ship]

I finally got off my rump today and pulled the engine and outdrive. Will photograph tomorrow and do some inspecting.

Knowing what many of us have gone through with our older boats I can't image the bill if the transom needs replaced. Not sure if I even trust a local boat shop to fix this. Summer is nigh and we don't want to miss out on another season of swimming.

Here is my original project from June 2016: https://forums.iboats.com/threads/2000-larson-186-lxi-project.673552/page-2#post-5023639

 

[Sunken Ship]

Figged it out...I think. When I bottomed out the washer plate was bent and an impression was made in the wood loosening the seal at the bottom of the transom. The seal being smashed for 21 years did not maintain elasticity allowing the leak to occur through the keyhole and out through the washer plate on the inside.

Seems solid to me... https://ufile.io/e7foqew8

Washer plate indentations. The mess under key hole is just poor resin/glass work at the factory:

 

[Scott Danforth]

I would make some test drills into that transom

it doesnt look "solid"

the tabing is busted underneath the key hole with a big crack, the wood has swollen at the key hole and is black.

the layers are separating around the perimeter of the keyhole which indicates that the glue/wood bond has failed.

I would drill 4 holes, all 1" above the bottom of the bilge with a 5/16" drill bit and drill 1" deep. if the shavings come out dry, light-tan in color and smell like fresh cut wood, you are good to go - just mix up some marine tex and fill the holes. However if the shavings are wet, dark brown to black in color and smell like rotten mulch or my hip waders after a week of installing docks...... transom time.