How much "Transom Flex" is too much...

[mbhoag]

OK, I have spent the last 2 weeks reading all the repair and rebuild postings, and what is involved in replacing stringers and transoms... so now I may just be paranoid... but I must ask the question.

So I was able to get out on the water today myself with my 1986 Bayliner 18' fiberglass bass boat (125 hp Force)... and I noticed that every time I gave it a little gas, there was movement of the engine, and the transome itself 'flexed' or moved a little...

I would make a guess that the movement or flexing was maybe 1/2 to 1 inch? (watching it from 5 feet away as I worked the controls) Is this normal, or do I need to pull my decks and start drilling core samples?

 

[NYBo]

Re: How much "Transom Flex" is too much...

That would be 1/2 to 1" too much flex, sorry to say.

 

[mbhoag]

Re: How much "Transom Flex" is too much...

That would be 1/2 to 1" too much flex, sorry to say.

Well crap... I was afraid of that... guess I am glad I was on a 'no wake' lake, and did not find out how much flex & give (or lack of give) it might have with a hole shot to WOT! :facepalm:

 

[ThrottleBack]

Re: How much "Transom Flex" is too much...

i dunno bout everyone else but if i can stand at the controls and SEE that the engine is moving at all it's too much

 

[Frank Acampora]

Re: How much "Transom Flex" is too much...



On an 18 footer, there should be NO flex of the transom. Just to be certain, while the boat is on the trailer and with the engine vertical, stand on the anti-ventilation plate and bounce. You should see NO transom movement.

Now if your transom IS flexing, I have had very good luck with capping it with aluminum and tying it into the splashwell. Beats taking the boat apart for repair. Done correctly, you will have a stronger transom than the original

I also have had very satisfactory results with Git-Rot.

 

[ThrottleBack]

Re: How much "Transom Flex" is too much...

View attachment 205242View attachment 205243View attachment 205244View attachment 205245View attachment 205246

On an 18 footer, there should be NO flex of the transom. Just to be certain, while the boat is on the trailer and with the engine vertical, stand on the anti-ventilation plate and bounce. You should see NO transom movement.

Now if your transom IS flexing, I have had very good luck with capping it with aluminum and tying it into the splashwell. Beats taking the boat apart for repair. Done correctly, you will have a stronger transom than the original

I also have had very satisfactory results with Git-Rot.

that engine cover is beautiful

 

[crabby captain john]

Re: How much "Transom Flex" is too much...

Normal-- no, not at all. Now time to check the stringers.

OK, I have spent the last 2 weeks reading all the repair and rebuild postings, and what is involved in replacing stringers and transoms... so now I may just be paranoid... but I must ask the question.

So I was able to get out on the water today myself with my 1986 Bayliner 18' fiberglass bass boat (125 hp Force)... and I noticed that every time I gave it a little gas, there was movement of the engine, and the transome itself 'flexed' or moved a little...

I would make a guess that the movement or flexing was maybe 1/2 to 1 inch? (watching it from 5 feet away as I worked the controls) Is this normal, or do I need to pull my decks and start drilling core samples?

 

[12thManFalseStart]

Re: How much "Transom Flex" is too much...

What is the stringers?

 

[MTboatguy]

Re: How much "Transom Flex" is too much...

What is the stringers?

The supporting structure that goes under the floor.

 

[crabby captain john]

Re: How much "Transom Flex" is too much...

What is the stringers?

1st,,, any soft spots on the floor? OK,,, stringers are what supports the hull, fore & aft AND port & starboard. They also support the floor and everything above it. Very often if rot is found in the transom, stringers, or floor it will be found in more than one area.

 

[12thManFalseStart]

Re: How much "Transom Flex" is too much...

1st,,, any soft spots on the floor? OK,,, stringers are what supports the hull, fore & aft AND port & starboard. They also support the floor and everything above it. Very often if rot is found in the transom, stringers, or floor it will be found in more than one area.

I'm not sure how to check the floor. Can't really get to it except for a small hole in the very back. I mean, the v hull of the floor, where the water drains out is a small square cut out about 10 by 10 inches. The floor you stand on is solid.

 

[MTboatguy]

Re: How much "Transom Flex" is too much...

You have jumped in with both feet buddy, you need to spend some time in the repair and restoration section of this forum, you will be amazed at how much you will learn, there is a lot more to a boat, than just buying and putting in the water, spend some time reading and learn.

 

[mbhoag]

Re: How much "Transom Flex" is too much...

I am fully aware of what & where stringers, transom and bulkheads are.

I did take a look at things and grab a couple of pictures. It is hard to see in Pics, but it looks like the PO had sealed up a couple of stress cracks where transom meets splashwell with some sort of silicone...I've had the boat 3 years and never really looked that close! (that was silly of me I know).

Also, you can see a slight bowing of the transom under the weight of the motor. I had noticed this before, but thought It was normal with a several hundred pound motor attached.

Last, is a very shaky video... it is hard to hold phone, video and wiggle motor at same time... but if you look closely you can see some 'give' in the transom as motor moves.

It may be a week or two before I can get started, but looks like I will be adding a teardown and restoration thread of my own to the forum. I wanted to remove and reconfigure my decks anyways, and add more storage space




Video

 

[NSBCraig]

Re: How much "Transom Flex" is too much...

Fix it right. Don't spend a bunch of time and money trying to slap some aluminum on it to make it "good enough". Good enough isn't good enough when it comes to everyone who is gonna ever get on your boats lives. No there is no way to do it correctly. (Sorry it's true) AND NO you will not have a transom stronger than it was originally. That's completely not true and (yep this one is harsh) demonstrates a complete lack of knowledge of boat construction.

To all the LEO's, Coasties etc who frequent this forum- Anytime you see a boat with an aluminum plate on the transom, the boats owner fully understands that their vessels is unsafe to operate. These are the first people you should stop and do a safety check on because they have already demonstrated a complete lack of concern for safety.

It's not that hard to fix right and there are a bunch of people here that have done it and will guide you through it.

 

[Frank Acampora]

Re: How much "Transom Flex" is too much...



In this instance DONT listen to NSBCcraig: With your Chrysler/Force, the engine clamps tend to bite into and deform the transom fiberglass. Eventually this causes the trim cylinder ram to move off the stainless seat on the steering yoke and trim will not work. The ram will simply move in free air, not against the yoke.

With your engine it is absolutely essential for continued good performance to use a minimum.080 thick hard aluminum plate on the outside of the transom, under the clamps. Do not go too thick or the transom clamp screws will no longer fit over the transom.

Usually, if you have repaired the transom, a plate about 16 by 16 inches is plenty large. You will need to drill a drain hole in it to match the splashwell drain hole in the transom.

 

[NYBo]

Re: How much "Transom Flex" is too much...

I have agree that in this case that puny piece of aluminum under the clamps is a tip-off to investigate further, especially with that crack at the splashwell. But hindsight is 20/20; thankfully you caught it before a catastrophic failure. Plus, this thread inspired another member to check his, discovering a major rot problem.

 

[pckeen]

Re: How much "Transom Flex" is too much...

I'm not sure that Frank and NBSC are actually disagreeing. NBSC is indicating you need to do a proper transom repair, and Frank is indicating that you need an aluminum plate on top of an already solid transom.....if I'm understanding them both properly. An aluminum plate on top of a solidly repaired transom would be the way to go. Slapping a metal plate on a rotten transom will be a bandaid fix.

The cracks and deformation in the transom you have look like you have a rotten transom - looks to me like it is ready to let go. I would not take that boat out on the water.

 

[mbhoag]

Re: How much "Transom Flex" is too much...

As you can see from these pictures, there are no plates on the outside of the transom, just the two metal plates on the inside under the clamp heads. After I pull it apart and replace/repair the transom, I will take the advice to add a single aluminum plate under the clamps so that they will not dig into the fiberglass.

I have seen plates under many many motor clamps in my life, I never gave them a second thought when I bought the boat a couple years ago.

I have no intention of doing a 'half assed' repair, it will be torn down and done correctly.

 

[NYBo]

Re: How much "Transom Flex" is too much...

I have no intention of doing a 'half assed' repair, it will be torn down and done correctly.

That's the spirit!:clap2:

 

[NSBCraig]

Re: How much "Transom Flex" is too much...

My bad. I didnt see your motor didnt have top bolts, just clamps. Yeah I would put something under them.