# transom extension for added flotation



## Rollbar (Oct 20, 2016)

These are out of stock, but when in stock, they are like $250.00 (if memory serves) AND they come in different sizes.
Amazon.com : Beavertail Float Pods Size: Small : Boating Tools : Sports & Outdoors 






Amazon.com : Beavertail Flotation Performance Pods, Large : Sports & Outdoors


Amazon.com : Beavertail Flotation Performance Pods, Large : Sports & Outdoors



www.amazon.com


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## ET101 (Sep 10, 2020)

I was kind of hoping for a cleaner, more permanent solution. I will be replacing floor, stringers and transom in the near future so I figured that would be a good time to glass up something to the back... just not sure how to tie it in to the raised transom to make it look good.


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## DuckNut (Apr 3, 2009)

ET101 said:


> I was kind of hoping for a cleaner, more permanent solution. I will be replacing floor, stringers and transom in the near future so I figured that would be a good time to glass up something to the back... just not sure how to tie it in to the raised transom to make it look good.


There is another thread on here about alternative ideas for a pumpless baitwell. Check that one out. Capt. Lemay has a great picture of his old skiff that had posd on the back which doubled as livewells. You can get some ideas from that.


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## ET101 (Sep 10, 2020)

Something like this.... would the transom just continue across like a bulkhead or would it go completely around the exterior?


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## jonny (May 1, 2007)

Is your boat glass or aluminum? I thought it was aluminum. Sounds you are saying glass. Not sure if your boat is sitting low. Or if that’s it’s design. Plus being a tunnel always hurts draft a bit. It doesn’t have much freeboard in the back at all. It’s kinda like a cut down panga. I bet you can gain a inch or two. By rebuilding the decks with foam core. And losing all that plywood. You could get by a smaller console as well.
You are right about being tough to tie into the raised transom. I would try to keep them low and flat. Not going all the way up. But just above the waterline. This will also save weight. This way you can use it as a entry point. Like a dive platform. Maybe even add a boarding ladder to the side.
A big issue you need to think about is the stress at the back. Which is a lot. My suggestion would be to extend the stringers from inside through the extension. By sistering them to the existing stringers. Or it sounds like you were planning on replacing them already. This will spread the load into the rest of the hull. And not have a high stress point at the back. Which would eventually fail.
If the draft is fine. Which it looks like about 8 inches or so. Which is pretty good. Another option is pull that cap off. Rip some foam or plywood about 4 inches. Glass it in raising your freeboard. Then put the cap back on.


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## ET101 (Sep 10, 2020)

The boat is fiberglass and is in need of work. I picked it up for 500 and so far am only in it another 800 or so rebuild the powerhead. I figure I have some room to do stuff to it before I exceed its value. I would like to get it to sit level while floating in the water. My plan is to build a deck for up front and put the fuel tank under that. I am also planning on building a much smaller console along with moving the gunnel cap from inside to outside... 7 more inches of deck space makes a big difference on this little boat. I know its not technically a poling skiff but I do believe it has potential to float pretty skinny with thought and weight reduction. I was thinking that added flotation on the back rear of the motor would aid in this quite well. Were you recommending to cut the transom flat across from gunnel to gunnel? I wouldn't necessarily be opposed to this but, I've only got maybe 4 inches of up adjustment left on manual jackplate and cutting out the top of the transom would remove around 7 inches. I liked the idea of building it like the picture I posted above... that would tie in the high transom center to the back of flotation. I was thinking that I could keep the transom where it is currently going across from gunnel to gunnel and gusset the sloped peice going rearward opposite the stringer so the transom would be sandwiched between them. Then fiberglass everything else. Do you think divinylcell would be strong enough for the flotation or would you think something like coosa? I attached some pictures of the "tunnel", more like a 20x20 pocket, along with how I would like it to sit in the water.


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## Smackdaddy53 (Dec 31, 2012)

Johnny an average sized skiff tunnel only adds another 1/8-1/4” draft if you do the calculations. I have it saved somewhere...here it is!


Captain Mac Jank
Zephyr Cove Guide Service

A tunnel that is 3" deep at the transom and slopes down flush with the bottom that is 14" wide and 32" long has about 672 cubic inches of volume. A cubic foot is 1728 inches and can float about 62 pounds. 
672\1728 is ~0.38 so multiply 62x.38 and you get 23.56# loss of bouyancy. That is just a rough tunnel size and shape, most tunnels have sloped sides so that is even less volume lost. Disperse that along all that wetted area of a hull and the draft loss is miniscule (like 1/4" with a man on the bow when draft matters most). I can see if it is a 6" deep tunnel that is 48" long and 18" wide like some of the aluminum tunnel hulls but most skiff tunnels I have seen are not very big at all...


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## Gogittum (May 24, 2020)

Your boat looks very similar to the 16 ft Glen L console skiff, but looks like yours has a tunnel hull. My last boat looked almost identical but was the 16 ft cabin skiff variation, (without the cabin) which had raised gunwales. With the freeboard yours is showing in the pictures, I'd be very spooky about taking it anywhere but a calm lake.

The suggestion about raising the gunwales sounds to me like a very good one.










Here's mine on the Lower Colorado River. Note the difference in freeboard - and this was in fresh water. This boat was a joy in all kinds of weather - and handled rough water extremely well. Note the compact console as well. Think it was a Todd product - very strong and very light weight. Motor was a 50 hp Tohatsu - no problem with flotation.


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## ET101 (Sep 10, 2020)

I'm curious as to how much weight is in wet 3/4 ply floor, wet transom wood and wet stringers. I imagine that after i go through everything with lighter material, I will get a bit more height out of the back. I am afraid that after I do all of that work, it will still need more flotation in the back. I dont want to go back into it after it gets done. Any harm in adding flotation off the back and not end up needing it?


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## jonny (May 1, 2007)

Yeah you can do a lot of weight savings. By using some foam core. No need for the real real expensive coring. You can get good core for about half of h80. I was referring to doing pods like you were saying. But just keep em low at water height. To use as a entry point. With that curved hull side. It will be tough to match. Unless you spray it with some pva. And pop a couple of quick temp molds off it on each side. Or just go with square boxes off the back. I would gut of the wet plywood. And see how she’s floating. Then go from there if it’s worth the work and money


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## ET101 (Sep 10, 2020)

Would you mind telling me what core you're talking about... i have seen nida and divinylcell. What other affordable options do I have? I'd like to do the transom in coosa or comparable... price depending. I have the budget to do good core and polyester or epoxy and wood... unless I use raka epoxy. I have heard good things about raka and its affordable.


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## JC Designs (Apr 5, 2020)

Carbon core is a good option for your core needs. They have poly foam, pvc foam, pe foam, honeycomb “nida core”, and a coosa comparable fiber reinforced pu foam. Tell’em I sent ya please!


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## JC Designs (Apr 5, 2020)

ET101 said:


> I'm curious as to how much weight is in wet 3/4 ply floor, wet transom wood and wet stringers. I imagine that after i go through everything with lighter material, I will get a bit more height out of the back. I am afraid that after I do all of that work, it will still need more flotation in the back. I dont want to go back into it after it gets done. Any harm in adding flotation off the back and not end up needing it?


3/4 ply weights around 60lbs per 4x8 sheet alone! Water log that at roughly 8.3 lbs per gallon and I am willing to bet you can shave a few hundred lbs off that chunky gal!

Remove the floor and weigh the pieces. If you go with pods/sponsons you may end up unhappy with the results. Os your jackplate manual or power?


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## DuckNut (Apr 3, 2009)

I am going to go against the grain here but hear me out.

Your boat appears to have a pretty solid deadrise and that will cause it to sit a bit deeper. The tunnel is not a hindrance. I also see a jackplate on there with a heavy azz motor. This additional setback is adding to your squatting. Somebody was led to believe that putting a jackplate on is the holy grail to solve the squatting issue of that heavy azz motor. Because the JP did not solve the issue but made it worse they bolted on trim tabs thinking this would help. Those trim tabs would not fit if that JP was not there as they appear they would not allow the motor a full turn.

My personal belief is that given the characteristics of the hull from your picture you may have the best your going to get. The hull is narrow with a good deadrise and a heavy azz motor. My suggestion would be to find a 25 2 stroke and hang that on the transom (remove JP) and see how she floats. I think the hull may be exceeding its capabilities.


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## ET101 (Sep 10, 2020)

JC Designs said:


> 3/4 ply weights around 60lbs per 4x8 sheet alone! Water log that at roughly 8.3 lbs per gallon and I am willing to bet you can shave a few hundred lbs off that chunky gal!
> 
> Remove the floor and weigh the pieces. If you go with pods/sponsons you may end up unhappy with the results. Os your jackplate manual or power?


Thank you for that source on composite materials... i haven't heard of them before. 
The jackplate is manual, i have about 1.5 inches available to go up on that and 2.5 left on actual motor mount to jackplate. 
The boat had filled with water and rolled in the slip on the previous owner. He craned it out of the water and never did anything with it then sold it to me 6 months later. I consider myself lucky to have been able to save the motor. 
What is the thinnest material I could go with for spanning 30 inch wide stringers? I was hoping to be able to use 1/2" material and raise it enough to be able to make it a self bailing deck. Thats the reason why it rolled in the slip... cold front came through and PO was out of town. 
I want to thank everyone for their input so far... it is greatly appreciated.


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## ET101 (Sep 10, 2020)

DuckNut said:


> I am going to go against the grain here but hear me out.
> 
> Your boat appears to have a pretty solid deadrise and that will cause it to sit a bit deeper. The tunnel is not a hindrance. I also see a jackplate on there with a heavy azz motor. This additional setback is adding to your squatting. Somebody was led to believe that putting a jackplate on is the holy grail to solve the squatting issue of that heavy azz motor. Because the JP did not solve the issue but made it worse they bolted on trim tabs thinking this would help. Those trim tabs would not fit if that JP was not there as they appear they would not allow the motor a full turn.
> 
> My personal belief is that given the characteristics of the hull from your picture you may have the best your going to get. The hull is narrow with a good deadrise and a heavy azz motor. My suggestion would be to find a 25 2 stroke and hang that on the transom (remove JP) and see how she floats. I think the hull may be exceeding its capabilities.


The hull is rated for a 70hp albeit 2 stroke. And the trim tabs are surprisingly factory original from 1989 the best I can tell. I believe you are not wrong to mention the deadrise and the boat is skinny at 66 inch beam but I think if I was able to lighten it up some along with move weight like an 18 gallon fuel tank up front, it will help. I dont expect this to be the best flats boat ever made or anything but I think that some of its issues can be corrected. In its original design, it was made to handle the bay chop to get to the flats. Thank you for the insight DuckNut.


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## JC Designs (Apr 5, 2020)

ET101 said:


> Thank you for that source on composite materials... i haven't heard of them before.
> The jackplate is manual, i have about 1.5 inches available to go up on that and 2.5 left on actual motor mount to jackplate.
> The boat had filled with water and rolled in the slip on the previous owner. He craned it out of the water and never did anything with it then sold it to me 6 months later. I consider myself lucky to have been able to save the motor.
> What is the thinnest material I could go with for spanning 30 inch wide stringers? I was hoping to be able to use 1/2" material and raise it enough to be able to make it a self bailing deck. Thats the reason why it rolled in the slip... cold front came through and PO was out of town.
> I want to thank everyone for their input so far... it is greatly appreciated.


Give me a bit and I’ll draw ya up a quick plan. 30” with 1/2” is doable but you might get some flex and would need to over glass to make “strong enough”. But there is a way...


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## JC Designs (Apr 5, 2020)

DuckNut said:


> I am going to go against the grain here but hear me out.
> 
> Your boat appears to have a pretty solid deadrise and that will cause it to sit a bit deeper. The tunnel is not a hindrance. I also see a jackplate on there with a heavy azz motor. This additional setback is adding to your squatting. Somebody was led to believe that putting a jackplate on is the holy grail to solve the squatting issue of that heavy azz motor. Because the JP did not solve the issue but made it worse they bolted on trim tabs thinking this would help. Those trim tabs would not fit if that JP was not there as they appear they would not allow the motor a full turn.
> 
> My personal belief is that given the characteristics of the hull from your picture you may have the best your going to get. The hull is narrow with a good deadrise and a heavy azz motor. My suggestion would be to find a 25 2 stroke and hang that on the transom (remove JP) and see how she floats. I think the hull may be exceeding its capabilities.


Damn you, I was getting to the jackplate and was going to suggest to him when he rebuilds the transom to build it higher to begin with.🤘🏻 Great minds buddy, great minds!😎


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## DuckNut (Apr 3, 2009)

ET101 said:


> The hull is rated for a 70hp albeit 2 stroke. And the trim tabs are surprisingly factory original from 1989 the best I can tell. I believe you are not wrong to mention the deadrise and the boat is skinny at 66 inch beam but I think if I was able to lighten it up some along with move weight like an 18 gallon fuel tank up front, it will help. I dont expect this to be the best flats boat ever made or anything but I think that some of its issues can be corrected. In its original design, it was made to handle the bay chop to get to the flats. Thank you for the insight DuckNut.


I might be a dick in a different part of the forum, but here is where people are asking for assistance and glad to help. I am glad you are being realistic, that is the first step to recovery.


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## ET101 (Sep 10, 2020)

DuckNut said:


> I might be a dick in a different part of the forum, but here is where people are asking for assistance and glad to help. I am glad you are being realistic, that is the first step to recovery.


I am open to ideas here... thats why I'm asking. If I had it all figured out... i wouldn't need to ask lol. I just looked at the transom and it looks like it would have to be built only 3 inches higher to make the motor sit where it currently is. I think that is definitely doable... though I would have liked to keep the jackplate. I see how the leverage increase of the motor hanging 6 inches off the back increases the weight on the transom. Thanks again for the help.
JC... i am going to replace the stringers during all of this so... i can possibly move the stringers in more. The best i could do is maybe 2-3 inches on each side and that would put them right on the edge of the tunnel.


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## State fish rob (Jan 25, 2017)

If your pulling console to replace stringers ,I would relocate it closer to the bow.


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## Smackdaddy53 (Dec 31, 2012)

State fish rob said:


> If your pulling console to replace stringers ,I would relocate it closer to the bow.


Stick it on the front deck like a crab boat.


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## ET101 (Sep 10, 2020)

I was thinking that... besides that... make it smaller too. It is a pain to walk around the console on that skinny boat.


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## ET101 (Sep 10, 2020)

Took it out for a test spin yesterday. Still working the kinks out on the motor but, it is now broken in enough to be able to get up on plane. Hopped up pretty well with the 40 and handled very well on plane. Hit wake and could barely feel it. Back of the boat comes up pretty good when on plane its just sitting still that the transom sits low. I had a buddy on the front and it did lift the back by an inch or so. I'm liking the way this boat is turning out. Still have some kinks to work out with the motor(had a coil failure on test drive) before i can start playing with weight loading in it.


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