TNT build progress

Outboard designs up to 14'

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upspirate

Re: TNT build progress

Post by upspirate »

Coming along great...I love the TNT's.

Is that a long shaft(20") engine? Did you build the transom higher for it?

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Gwoloshyn
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Location: Upstate NY

Re: TNT build progress

Post by Gwoloshyn »

Thudpucker, I think I would rather have an engine! :lol:

It's a 1982 40hp mercury, I believe it's a short shaft but the guy who I bought it from wasn't sure. Now that you mention it, I will measure it tomarrow to make sure it's a short shaft because no, I didn't build up the transom.. I built it to spec from the plans. I will probably be adding additional bracing in the motorwell area just for peice of mind.

If it does turn out to be long shaft (hope not) I could always block up the transom for it, right?

upspirate

Re: TNT build progress

Post by upspirate »

You can build the transom up higher still at this point if you need to. I would also add some additional height where the coamings contact the sides of the transom....maybe starting with a nice sweep from the dip behind the dashboard up to the higher point where you would be the same distance from the transom top as in the short design.

Figure out how high proportionally you need the transom on the profile view on the plans,and draw a coaming shape that pleases your eye.

To determine what motor you have,set the motor upright, set the clamp bracket angle the same as the transom,then measure from the underside of the bracket where it will sit on the transom straight down(plumb) to the cavitation plate above the prop.

This should be around 15 3/4' for short,20 1/2 for long shaft.

To determine how much to add to the transom,I clamp a stick to the cavitation plate,and one to the transom bracket, then measure the distance from where the motor sits on the transom down to the other stick. This is how high to make your transom.I like to run my plate even with the bottom of the TNT's and have had good luck with that height.

I can take a pick and show you what I mean by all this if you need.

upspirate

Re: TNT build progress

Post by upspirate »

Here is what I meant.
This is of a 1959 Mercury Mark 15-A with approx 14 degree set-up for the transom
IMG_0206.JPG
Now here is the straight down height for this motor....approx 16 1/2"
IMG_0209.JPG
Here is the height to make the transom....approx 16 3/4"
IMG_0210.JPG
On TNT's (a fast light hull)I set the motor so the plate is even with the bottom of the boat more or less.,in this case I would make the transom about 16 3/4 long to achieve this.

You may have to play with the height some to get what you want....with stock motors and stock props ,I have gone as much as 3/4-1" above the bottom on light fast hulls.

You may have some ventilation, (cavatation) if so, a cupped prop helps or you need to drop the height some.

I think most manuals say to run the engine height about 1" below the bottom on average hulls...you can set up for this and shim up if you want

upspirate

Re: TNT build progress

Post by upspirate »

On my skiff, I made the transom 16" long as it's not a high speed set-up and will run this Merc 15 on it.....that may still be too high and will have to cut some....we'll see
Attachments
IMG_0211.JPG

upspirate

Re: TNT build progress

Post by upspirate »

If you need to build up to a long shaft height,we can consult with Oyster and come up with a plan.

I'm familiar with the TNT plan and he's built up transoms before

I have some ideas(never done it before) but between us we can come up with a plan that'll work and look good

Just don't go any farther with the motorwell/coamings before you know what you have and what you might need to do

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Gwoloshyn
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Location: Upstate NY

Re: TNT build progress

Post by Gwoloshyn »

Sounds like a plan. I was going to add some height to the coaming anyways to create a back storage compartment behind the seats complete with a locking lid and hatch.. so if I need to raise the transom it will blend in just find with everything else. I will update tomarrow once I find out what kind of motor I'm working with.

How exactly would I go about raising the transom? If I have to, I will be adding some kind of stock but how would I secure it to the existing transom to form a ridgid place for my motor to ride on?

upspirate

Re: TNT build progress

Post by upspirate »

At this point,with your inside motor board in place,I would laminate an outside skin over the whole transom up to the proper height.I would add a piece to the top of existing transom to give the height, and a lamination on the inside over the existing motor board.

Not sure how thick your clamps will hold,but I bet you could fit this in just barely.

The way the coamings screw in from the side will support the added height if you use higher coamings.
I THINK this will be enough,but you would need to talk to Oyster.

As an alternative,if you would need more than say 1/4" on the inside for strength,you could use thicker plywood laminate, and just relieve an area for the clamp screws of the motor. Or....cut the inside motorboard down to the top of the motor well bottom( or all the way to the keel )and replace that part with proper height....that would be most work, but strongest.

Just my thoughts,check with Oyster.

Lets hope you have the proper height and this is just Fri night rambling!!!

One other idea to ponder....make up a new proper height motor board, same width as the inside one, and through-bolt it to the existing transom like a jack plate

upspirate

Re: TNT build progress

Post by upspirate »

Bright side to all this, is you caught it now....the farther along, the harder to fix! :wink:

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Roberta
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Re: TNT build progress

Post by Roberta »

Good to catch it now, for sure. Some of the older Mercs were 15 1/2, 16 1/2, 20 , 20 1/2, and 21 1/2 inches. Best to modify the transom while it is still easy. Pirate's idea is what I would do if I had to.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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Dave Grason
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Re: TNT build progress

Post by Dave Grason »

Message to all forum members that have NOT yet attended a Gathering:

You probably have not gotten to meet UPSPirate in person. He has attended every Gathering that we've had so far and is definately one of the family. He's a wealth of knowledge about boats. When he gets to talking about general boating knowledge, I shut up, listen intently and learn. But here's what's amazing about him. He has yet to bring a boat of his own building to the G. He's brought other people's boats, he's brought production boats. But he hasn't yet brought one that he built himself. :twisted: Haha Warren, you need to poopy or get off the potty. :lol:
Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

Oyster
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Re: TNT build progress

Post by Oyster »

Just my thoughts,check with Oyster.
LOL! I am slowlllllllllllllllllllllllllllllllllly learning that the older I get the less I know. Just ask me how I know that? :wink:


Dave, in regards to Pirate, truer words has never been spoken, at least this week anyway.

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Dave Grason
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Re: TNT build progress

Post by Dave Grason »

LMAO!

Mike, we need to just start a thread called: "POP"

That means "Pick on Pirate." It could just be a wonderful place where the entire intent is to keep Warren from getting a big head. :lol:
Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

Oyster
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Location: North Carolina

Re: TNT build progress

Post by Oyster »

Dave Grason wrote:LMAO!

Mike, we need to just start a thread called: "POP"

That means "Pick on Pirate." It could just be a wonderful place where the entire intent is to keep Warren from getting a big head. :lol:
You mean we should gather in a great big circle and have a big sing=a=long and have a roast a Pirate day?

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Pirate's Wench
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Re: TNT build progress

Post by Pirate's Wench »

Dave Grason wrote:Message to all forum members that have NOT yet attended a Gathering:

You probably have not gotten to meet UPSPirate in person. He has attended every Gathering that we've had so far and is definately one of the family. He's a wealth of knowledge about boats. When he gets to talking about general boating knowledge, I shut up, listen intently and learn. But here's what's amazing about him. He has yet to bring a boat of his own building to the G. He's brought other people's boats, he's brought production boats. But he hasn't yet brought one that he built himself. :twisted: Haha Warren, you need to poopy or get off the potty. :lol:
You can bet if the skiff was ready to be painted we would have brought it along with enough paint brushes to go around. Then we could have had one of those famous Dave Grason "Paint-a-Longs" :lol:
~~~Never walk in the footsteps of others, or you won’t leave any of your own.~~~

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