Transom question

[Johnshan1]

I have a 15' center console that I built, we just bought a new engine for it (160 lbs 40 hp Tohatsu) and the transom seems to flex a touch when i tilt the engine all the way up and push down on the leg of the engine, it is 1 1/2" thick made of 3 sheets of 1/2" ply I used west system to hold it together.<br /><br />I am going to add an aluminum plate to the transom to stiffen it up, do you guys think im all set or should I worry about that little bit of flex? Thanks a lot.<br /><br />PS- the boat is just 1 year old so there is no rot anywhere.<br />-John

 

[phatmanmike]

Re: Transom question

your transom should NOT flex at all, unless you have a jon boat.... otherwise flex is bad!!!!.. drill a small 1/8 inch hole through the transom, not under the water line, and check the drill bit for moisture. make sure to seel it up with GIT ROT or MRINE TEX... just an idea<br /><br />flex is bad...<br /><br />did i say that flex is bad...

 

[G DANE]

Re: Transom question

How much load do you put on the motor leg ?<br /><br />If your transom is only supported at the gunwhales and by buttom of the splashwell, a 1 1/2" ply transom will always be forced to flex a little if you put lots of weight on motor leg. Try to watch motor carefully during hole shot, from boat lying still. The motor will flex in its mounts, but do you observe the transom flexing too ? If it does flex visible, you will have to get someone with more experience to look at you boat. If it doesnt, I think your OK.

 

[G DANE]

Re: Transom question

If it is possible, get the aluminium plate bent 90 deg in top, and make it cover upper edge of transom, in the internal engine notch, will add much more strength. Be sure to seal under it or water will gather there.

 

[Boomyal]

Re: Transom question

Is your hull made from wood? You may want to add a knee from the middle of the transom to the floor. Bolt it up from the bottom and thru the transom then glass every thing over.

 

[Winger Ed.]

Re: Transom question

Originally posted by Johnshan1:<br />1 1/2" thick made of 3 sheets of 1/2" ply <br />-John

With that small a motor, you should be OK. Next time around, you might try 2 pieces of 3/4 plywood instead of the 1/2".<br />It should be stiffer for the same size & weight.<br /><br />Something I did on a hull once when it seemed to bow out it flexed so much while under way, was just put a piece of 1 1/2 x 1 1/2 Aluminum angle stock (3/16ths thick)I scrounged somewhere across the top of the transom under the engine brackets going across the transom to the outboard edges of the motorwell. <br /><br />Ed.

 

[ob15]

Re: Transom question

Johnshan1 <br /><br />it's the same guy from Bateau.com (same boat). I'm Surprised your transom is flexing. Mine is solid as a rock with a 50 on it (190lbs). I am assuming you put the motor well in it. The plate should work or maybe just some 2 by's across it where the motor bolts in. <br /><br />Wait til you get that 40 on. You'll have a blast with it.

 

[Whit]

Re: Transom question

Hi John, That's the last thing I want to hear as I am just finishing up the same boat. (with a Yamaha 50)Is it the wood itself that's flexing or does it feel like it's moving where you tied the transom into the hull? <br /><br />I agree that it's VERY unlikly you have any rot given the age and that you used marine ply and epoxy. Check and make sure the taped areas have not delaminated or come loose. To firm up the wood itself, another layer of Biax would probaly be easier than a metal plate. Also, I forget who, but someone who built around the time you did built an extra compartment in the splashwell for a bilge. It's shown on one of the builders websites. That would stiffen the transom quite a bit. Good luck

 

[Johnshan1]

Re: Transom question

Thanks to everyone!<br /><br />I guess I should have said this first- I built the boat for a short shaft engine. <br /><br />I striped the transom down to 1/2" (1 layer of plywood) and then added another 2 sheets of the correct height to allow the use of a long shaft engine.<br /><br />The problem was the splashwell was then too low to offer any support. I built 2 storage compartments on top of the existing splashwell to really give some good solid support.<br /><br />I guess I am more paranoid then anything, I dont see much in terms of flex (heck maybe its in my head???) perhaps 1/8" with the engine all the way up and a good amount of force down on the leg.<br /><br />I must say I epoxy'ed the living heck out of this thing and with the extra spports I added (the 2 compartments) I doubt I will have any problems, but I am just paranoid.<br /><br />I think with the addition of a metal plate there will be no flexing at all.<br /><br />I will hafta get some pictures on here to show everyone. <br /><br />In the mean time keep the thoughts comming

 

[Johnshan1]

Re: Transom question

By the way its the wood itself in the middle flexing not the points of attachment. All my layers of Biax epoxy are just fine.

 

[ob15]

Re: Transom question

Don't want to change the subject but Whit, You're building the OB15? Got mine done right before xmas and am loving it.

 

[Johnshan1]

Re: Transom question

I must say I love mine too, the tree did some damage but the boat is 10 times better than before, and I did get a payout of $1000 from the insurance adjuster for damages. It was roughly $200 in materials to get it to its original form again <br /><br />I should be back on the water with the new tohatsu 40 within 3 weeks, cant wait!

 

[heatherjoy]

Re: Transom question

heres a picture of our boats transom:<br /><br />

<br /><br />Please give us some ideas or thoughts, John said he wanted to put a plate on the inside of the transom area where the motor clamps, the only part that flexes is lower part of the transom where the motor clamps.<br /><br />Thanks!

 

[ob15]

Re: Transom question

How far down is the bottom of the motor well? It looks a little low but could be wrong (I mad mine higher so it could be right). Does the motor come with holes in the mounting plate below the clamps? If so, permanently mounting the motor with 4 bolts would probably stiffen it up real good. A plate should be fine also. It would have to be thru bolted to the transom. Probably easier to mount the engine instead.

 

[bidlimit]

Re: Transom question

I'll bet your fine...but two knees wouldn't hurt either.

 

[Johnshan1]

Re: Transom question

Thanks guys.<br /><br />Dave- I made the splashwell with the intent to use a short shaft engine, thats as high as it would/could go then.<br /><br />My new engine of course, is a long shaft <br /><br />The motor bracket extends to below that splashwell actually! Its a huge huge bracket, and I never thought that alone would stiffen things up but I bet you are right.<br /><br />Thanks guys.

 

[ob15]

Re: Transom question

Been out of town (fishing of course). Did you get things taken care of?

 

[Johnshan1]

Re: Transom question

Hey Dave,<br /><br />I waited to respond until it was all finished up.<br /><br />The boat is being launched tommorow! I need to get some new pictures the thing looks great I think, I used 72 feet of 1 1/4" oak trim when it was all said and done through the boat.<br /><br />Back to the transom, I got a peice of 1/2" aluminum plater, 10"x24" and bolted the engine down. <br /><br />I must have been just paranoid, because I can stand on the cavitation plate and nothing moves at all! This thing is nice and solid to say the least (knock on wood).<br /><br />I will have some pictures and a reveiw of the tohatsu engine as well, stay tuned

 

[Johnshan1]

Re: Transom question

Well I dont have pictures yet <br /><br />The boat performs great as always, even with the new transom. The 40 hp Tohatsu doesnt flex it at all, after an hour I applied full throttle, since it was very rough i didnt get a chance to run it this way for long, but I will say that its plenty fast enough, I cant say I would want to go any faster unless I had a totally flat day.<br /><br />I would guess 30-35 is the speed we saw, I will know more once its fully broke in.

 

[Johnshan1]

Re: Transom question

33 mph on the GPS, plenty fast for this boat.<br /><br />

<br /><br />

<br /><br />Just need to sand down those ugly hatches and varnish to match the rest of the oak, and then throw another coat of paint on the outside, the Interlux paint I used last year sucks if I must say so, Petit this time around should be better.<br /><br />Not too bad for a homemade boat huh?