Transome making a cracking sound on occasion, why?

[Colorado1135]

when I use my outboard (9.8 merc on a 14' lund) once in a while I hear a pop or crack sound, once a trip maybe. sounds like someone whacking it with a stick when I'm running full speed (which isn't much). last night it happened again and I had a tiny bit of water in the boat when I got to the ramp. is my transom bad and I need to replace it?
how big of a job is it?

the first time or two it happened I thought I ran over a chunk of wood or something in the water, after last night I think I might have a problem. :?

 

[Johnny]

first of all, how OLD is the transom ? any idea ?
PHOTOS of your rig can help us help you.

since you have a small motor, and most likely a tiller steer,
I would remove the motor and try to take "tissue samples"
of any existing holes you have in the transom. As well as the
ends if you can get to them ok. Plus the pressure test.
Take a screwdriver and poke around on all the wood you can get to.

If any of this wood looks like dry rot or not sound, time to replace.
If the transom appears to be sound, you may have some metal fatigue
somewhere in the hull is flexing under stress of the high speed.

you are correct to be concerned.

 

[crazymanme2]

Something on your transom is cracked.

 

[Colorado1135]

first of all, how OLD is the transom ? any idea ?

since you have a small motor, and most likely a tiller steer,
I would remove the motor and try to take "tissue samples"
of any existing holes you have in the transom. As well as the
ends if you can get to them ok. Plus the pressure test.
Take a screwdriver and poke around on all the wood you can get to.

If any of this wood looks like dry rot or not sound, time to replace.
If the transom appears to be sound, you may have some metal fatigue
somewhere in the hull is flexing under stress of the high speed.

you are correct to be concerned.

no idea on the age of the transom, I'm guessing original from '73 when it was made. I tried to see if I could see any wood but the whole thing seems to be covered.
I tried thumping on it to see if any of it sounded bad and it sounded solid, but if it was it wouldn't be making a pop or crack sound. the first trip I took it I recall it happened 2 or 3 times. I figured it was because it hadn't been out in years and just had a little stiffness to work out? probably sounds bad saying that.
if I keep from running the outboard full speed and rely on the trolling motor 95% of the time will she hold up til september? that way my fishing season won't be shot and I'll have the winter to work on it (slow season). right now I'm busier than a... well I'm pretty busy lets say.

 

[CMOS]

A possibility: when I first took out my 1963 tinny I also heard a couple loud pops, or more specifically what sounded like someone smacking the hull with a big screwdriver handle.

Turned out to be 2 snapped rivets. Easy fix.


CMOS

 

[Colorado1135]

A possibility: when I first took out my 1963 tinny I also heard a couple loud pops, or more specifically what sounded like someone smacking the hull with a big screwdriver handle.

Turned out to be 2 snapped rivets. Easy fix.


CMOS

were they completely missing or loose? how did you locate them, just visually and feeling them I would assume

 

[juggernot]

While on the trailer you should be able to see/hear if the transom is cracked by rocking the engine up and down while looking at the transom. If you see it flexing/bowing/bending etc. it prolly needs repairing. It likely has rotten wood inside the metal.

 

[Captain Ahab]

Make sure your motor is tight on the transom. If my motor gets a little loose it makes that noise

Also - when was the last time you greased the pivot on your motor?

 

[CMOS]

A possibility: when I first took out my 1963 tinny I also heard a couple loud pops, or more specifically what sounded like someone smacking the hull with a big screwdriver handle.

Turned out to be 2 snapped rivets. Easy fix.


CMOS

were they completely missing or loose? how did you locate them, just visually and feeling them I would assume

Not missing! The heads where still in place, but I would wiggle the seat that they were placed into. Usually I could see a minor shift in the position of the rivet head, just enough to see the old paint (or no paint) under the head.


CMOS

 

[Colorado1135]

I will check all those things, thank you all for the tips on where to start looking. I agree the wood is likely bad or going bad since it is that old, and that has been on my radar to fix this winter already.
the motor was greased this past winter so I don't think it would have been that.

Thanks Guys!

Ryan