Transom rot !!

[shaw520]

Well the work has started, outdrive is off,..engine is out. Weather turned wet today, next step start ripping, cutting and grinding.

 

[shaw520]

Re: Transom rot !!

Its a 1980 Thompson Sportmen that Ive owned for nearly 20 yrs, I put a fresh 165 Merc in end of last season and runs great, this season I discovered the transom rot. Vacation planned for Aug 22nd, so I need to get the transom rebuilt, engine and drive back together before then.
Tell me,... why do some of these manufactures neglect to glass the inside transom ????

 

[Woodonglass]

Re: Transom rot !!

Welcome to iBoats!
So you can have all this FUN!!!!! Twenty years later. Just think for an extra 50 bucks they coulda/shoulda dun it and you could be havin fun doin sumthun else

I'm just sayin...

Good luck to you on your rebuild

 

[RobbyA]

Re: Transom rot !!

Vacation planned for Aug 22nd, so I need to get the transom rebuilt, engine and drive back together before then.

That's a pretty hefty goal! I hope you're taking more vacation before then to do all the work.


ETA: Spelling....grrrrr.....

 

[shaw520]

Re: Transom rot !!

That's a pretty hefty goal! I hope your taking more vacation before then to do all the work.

Yea! curious to see how much of the transom has to be replaced

 

[oops!]

Re: Transom rot !!

welcome to i boats.

get your wood now.....i suggest at least one layer of one inch ext grade ply...make up the rest with what ever thickeness ply you need. the one inch ply is a really stable wood to work with....

you might get a one inch and a three quarters, and the rest of the thickness will be glass.

engine and out drive removal...= 4 hrs
transom removal = 6 hrs avg (it varies)
hull prep = 2 hrs
clean up = 1 hr
transom build = 3 hrs avg
instllation = 1 hr
cure of instlation = overnight
glassing and cure = 3 hrs
tie ins = 6 hrs avg
cutting the hole and glassing = 2 hrs
gellcoating bilge and new transom = 1 hr
paint bell/ drive /housing = 1.5 hrs.
re instllation of housing = 1.5 hrs
motor installation = 3 hrs (includes hook ups)

these are professional times.....and all times vary
for a first timer.......triple all numbers !
a first time dyi can do a transom in 40-70 hrs depending on skill level.

we just did a 32 footer with twins (bravos) in under 28 working hrs total.

the only time the work slows down is when you dont know what to do next or how to do it.

we are here to give you all the help you need or want....post if your stuck and we can assist quick.

cheers....and good luck.
oops

 

[Friscoboater]

Re: Transom rot !!

You need to see my thread. I have alot pof pictures and videos of transom stuff there. It is in my sig.

 

[shaw520]

Re: Transom rot !!

Thanks guys,.. Ive actually been following both your threads and they've been very informative. My transom is 2" thick so I'll be using two layers of 1" ply. I wont know exactly how big of an area yet till I get out all the rot and find where the wood becomes stable again.
Frisco, did you have any issues with the PL not curing, sometimes large quantities in sealed areas I've seen where it will not cure.??
Ooops, your work times seem spot on, took me 4 hrs to set up rigging, remove engine and drive. Ive done no less than 5 deck/stringers jobs before (including this very boat), but this will be my first transom. Also going to be adding knee supports that where never there before.

 

[shaw520]

Re: Transom rot !!

Ok, well the pulp goes on... after removing approx 50% of the transom I can now see that the inboard stringers are also pulp, so ive removed athe main inboard stringers about 4-5 ft forward of the transom. Updated pics to come tomorrow.

Question; Whats the best way to join the new stringer sections to the transom, ...use pb and 3" strips of cloth at the joints?

 

[Friscoboater]

Re: Transom rot !!

I never had any issues with the PL not curing. I had to take out some of my stringers too, and I used PL and 1708 to join to the new transom.

 

[Woodonglass]

Re: Transom rot !!

Just curious where you get 1" plywood. I don't have any supplier that can provide it in that thickness in the ext. grade. Also where do you plan on applying PL in such quantities that you are worried it will not cure?

I'm just sayin...

 

[oops!]

Re: Transom rot !!

best way to join the stringers is a lap joint (some people call it a scarf joint)

this is where you carve away half the thickness of stringer and over lap them.
(its in my hull thread)

some people "sister the stringers" by sandwiching them in between two pieces of wood. the latter is easier.

but either one, once its all glued, screwed, and glassed......its strong.

cheers
oops

btw.....if you have an i/o (sorry i cant remember)
after you add the glass and thickness of the hull. the two one inch pieces of ply will make it too thick for a mercuriser set up.
this means you will have to router away the top layers of glass and wood, then start playing with flatness and paralellism at the transom plate......and that is a can of worms bud.
use one 1 inch and one 3/4 inch the rest is made of glass and the lamination layers.

cheers
oops

 

[Stampeder]

Re: Transom rot !!

Oops:

Not to be too picky but a lap joint and a scarf joint are different.

A lap joint is where one piece of wood is overlapped by the other. Usually each piece is dadoed in half.

A scarf joint is where they both are cut on an angle and then jointed together. Usually this is done at 45% angle but can vary. Scarf joints will usually used where movement will not expose what is in behind, usually for cosmetic reasons.

Worked in the Shipyards in Ontario growing up......learned a couple things from the shipwrights. Carpentry on boats is the most challenging work of all.

In this case I agree with you that the lap joint would be the better choice. I would also use wooden dowels to pin the joint for some added strength. Not that it would need it as the glass and matt will do a job. Just my finicky way of doing things.

Cheers.
Glenn.

 

[Utahboatnut]

Re: Transom rot !!

I would go with two layers of 1/2" ply and one layer of 3/4" ply getting 1" ply is tough.

 

[Yacht Dr.]

Re: Transom rot !!

2 layers of 3/4 ply is 1.5" + .5" of glass is 2"

Mercs I think have to be mounted within 2-2.25" of transom thickness..

However.. they are very specific about mountings ( Drives should be squared up ). .. .. DIY ? aye.. more cost in the near future screwing it up..aye..

Hey its your drives m8s.. IF You dont know.. then you probably should not be the final say so..

Think of transoms with outboards to your wife .. Seldom do they conform..and never do they d'agree ( pun hehe )..

Im no expert..

YD.

 

[shaw520]

Re: Transom rot !!

after you add the glass and thickness of the hull. the two one inch pieces of ply will make it too thick for a mercuriser set up.

Yup!,.. good point oops, I forgot I'll be adding glass to an area that wasnt glassed before, so 2 layers of 3/4 with 1/2" of glass will put me there.

I already had in mind that I would sister the stringers in,... but my question was how to join the new stringers to the new transom?? ...maybe some resin peanut butter with 3" strips of cloth, then glass everything over?? I want alot of strength in this area to minimize transom flex, hence why I'll be adding knee supports as well.

 

[shaw520]

Re: Transom rot !!

Some progress, transom section is PL'ed and clamped in place. Stringers and knee supports next. Alot of work doing the transom no doubt!!

 

[oops!]

Re: Transom rot !!

Oops:

Not to be too picky but a lap joint and a scarf joint are different.

lol....this depends on the

1.area you live in.
2. the internet page where you see the joints.
3 the guy that taught you.
4. the sobriety of the guy that came up with the idea in the first place.

LOL....

i know joints have totally different names in different areas. in my own thread there is a detailed section on lap joints, and a very well known poster mentioned in his area it was called a scarf joint.

 

[oops!]

Re: Transom rot !!

as far as the transom wood thickness....

i really love the one inch product as a base....man that stuff is rigid.....if it does warp during drying...it is very little. from now on all my transoms will be started from a one inch base and built out from there.

another factor in the thickness of an i/o transom......you want all the glass to be of a uniform thickness in the plate area. if not you will end up playing with flatness and parallelism....that can be a real pita.

 

[shaw520]

Re: Transom rot !!

as far as the transom wood thickness....

i really love the one inch product as a base....man that stuff is rigid.....if it does warp during drying...it is very little. from now on all my transoms will be started from a one inch base and built out from there.

another factor in the thickness of an i/o transom......you want all the glass to be of a uniform thickness in the plate area. if not you will end up playing with flatness and parallelism....that can be a real pita.

....good advise right there

BTW,.. thought I should mention that in the progress of removeing the rotted wood, I discovered that the moisture that caused this problem was getting in through the screw holes that mounted the swim platform. The previous owner had installed a swim platform (27 yrs ago) when the boat was new, and even though he sealed the screw holes, he didnt properly chamfer the gelgoat, so they 'spidered'.