12' porta bote mod project - progess report

[thomasiam]

hi guys.
BTW thanks for all your help and guidance in modifying my new 12' porta bote to handle a 9.9 HP motor.
here are some mods i did for the past few weeks. the original design was done by Stepperbill plus my own add ons.

first and foremost issue was beefing up the transom to be able to handle the weight and thrust of my new 9.9 hp motor.

to do this i got my hands on pourable structural foam and filled the transom cavity. simple two parts mix and pour into the holes i made on top of the transom. it's a closed cell foam.



after that i got some 1/4" aluminum to make the transom support.


the cross "L" bars are welded into the back plates and bolted through the transom.

I added more bolts to the side support. so total of four on each side where the transom is attached to the boat.



lastly i installed a square bar under the seats from bow to stern. the bar was fastened using "closed fastener".



i'm ready to hit the water this weekend i think.

i'm not sure if i want to install U beams on the floor of the boat since that means making so many holes to install it. will see.

 

[barato2]

Re: 12' porta bote mod project - progess report

nice work dude! did you do the TIG welding yourself? i may have to steal your longitudinal support bar idea....i'd like more rigidity but agree with you on fears regarding punching 20+ holes in bottom of hull.

let us know how it works out on the water!

 

[thomasiam]

Re: 12' porta bote mod project - progess report

nice work dude! did you do the TIG welding yourself? i may have to steal your longitudinal support bar idea....i'd like more rigidity but agree with you on fears regarding punching 20+ holes in bottom of hull.

let us know how it works out on the water!

thanks. the welding is technically not welding.. didnt want to get $400 aluminum welding gun for my MIG welder just to do this. ordered DURA FIX Dura Fix Aluminum Welding Aluminum Brazing Aluminum Soldering & Repair Rod is not sold on Ebay US or Amazon seems to work well for this application and only need a MAP gas to do it. just have to do some practice. i also bolted the metal to the transom as insurance.

for the longitudinal support what i did was drilled a bigger holes on one side of the square bar first every 8" or so. than you can position the bar where you want it under the seats. Than you can dill a smaller hole through the bigger hole where the closed fastener can be placed from the out side. seems to work well.

oh ya. every important. you need to bend the bar just a bit towards the front to make it fit with in the boat. you can do that by heating the aluminum bar where you want to bend it with a torch. it's extremely helpful to have a bench clamp. if you get your bar from Home depot the thickness of the metal is so thin it will only take a min to heat the metal to bend. i decided to use a square bar and bend it instead of L beam most people use with notch cut out. i thought once you notch the bar you lose the stiffness of the bar so what is the point.

let me know how it works out for you.

 

[barato2]

Re: 12' porta bote mod project - progess report

ah...you just answered the one Q i had about the side bar. does it seem to affect foldability of your boat?

 

[thomasiam]

Re: 12' porta bote mod project - progess report

ah...you just answered the one Q i had about the side bar. does it seem to affect foldability of your boat?

it will due to the angle of the bar and the thickness of the square bar. have to give something to get something back.....i my case well worth it.

 

[barato2]

Re: 12' porta bote mod project - progess report

hmmmm...i may try using the U-channel like Stepperbill used for his floor, bolted to the sides where you have the square bar. i need mine to fold down normally since i have to haul it 700 miles on top of camper to my fishin' hole

 

[thomasiam]

Re: 12' porta bote mod project - progess report

Great news. the boat worked great over this weekend.


the only issue was i could not go over 50% of the throttle due to too much water coming in from the bow due to splashing. Faster you go more water splashes in. fastest i took it was 9 NM.







have to put in a pump to get the water out.

So my personal review about this boat is great to take out in calm waters with electric or up to 6hp motor. 10 hp is bit over edge for this boat. I'll keep this one for local ponds or rivers but most likely have to get a bigger boat next year if i want to do some joy ridding around the bay or bigger lakes.

from canoe to porta-bote to bass boat here i come...... this hobby is getting bigger and $$ every year...

 

[thomasiam]

Re: 12' porta bote mod project - progess report

btw. hats off to those that take this boat to the ocean. you guys are brave (crazy more like it :fear . this boat really rocks in the waves.

 

[MustardKeen]

Re: 12' porta bote mod project - progess report

Well done Thomasiam.
Could you please tell me what "closed fastener" is?
Have you had a chance to try it out yet?
I was contemplating getting a sheet of 1/4" aluminium, cutting it to the shape of the transom and fastening it to the transom.
I assume you put the additional bolts in the side transom support above waterline.
Thanks again

 

[MustardKeen]

Re: 12' porta bote mod project - progess report

Great news. the boat worked great over this weekend.
View attachment 213716

the only issue was i could not go over 50% of the throttle due to too much water coming in from the bow due to splashing. Faster you go more water splashes in. fastest i took it was 9 NM.

View attachment 213713

View attachment 213714

View attachment 213715

have to put in a pump to get the water out.

So my personal review about this boat is great to take out in calm waters with electric or up to 6hp motor. 10 hp is bit over edge for this boat. I'll keep this one for local ponds or rivers but most likely have to get a bigger boat next year if i want to do some joy ridding around the bay or bigger lakes.

from canoe to porta-bote to bass boat here i come...... this hobby is getting bigger and $$ every year...

I thought that Boat stood for "Break Out Another Thousand". It seems that boating can be an expensive pastime.

 

[barato2]

Re: 12' porta bote mod project - progess report

and when you hit 30', it becomes BOATT....break out another ten thousand.

Mustard----that would be gross overkill and add a lot of weight. you can get adequate strength with something a lot lighter.

Thomas--look at the pix of how i have mine set up. i made a big bow cover due to that very problem you mention.....1/2" ply cut to roughly follow shape of bow, with a "flap" of old motorcycle inner tube hanging down to cover the "snoot" of the boat, and a "v" shaped dam on the top to divert any water that comes over it to the sides instead of into the boat. i won't claim this about many of my "fixes" but this one has done exactly what i hoped and worked just as designed. i've had waves come over the bow many times, and they just run off the cover and stuff in the bow stays drier than anywhere else in the boat. i just affix it to the boat with nylon rope ties right now but am working on something better. and hey....you live in NJ and you're calling other people brave?

 

[thomasiam]

Re: 12' porta bote mod project - progess report

Well done Thomasiam.
Could you please tell me what "closed fastener" is?
Have you had a chance to try it out yet?
I was contemplating getting a sheet of 1/4" aluminium, cutting it to the shape of the transom and fastening it to the transom.
I assume you put the additional bolts in the side transom support above waterline.
Thanks again

sorry the tech term is blind rivets, closed end

I got mine here Blind rivets, Closed end (sealed), Dome head, Aluminum - Aluminum mandrel - Bolt Depot

on your idea of cutting a sheet - the issue is you have to sandwich the hollow transom with two sheets. one side will not be enough in my opinion. unless you have one sheet on one side and L beam on the other.

yes i put in two extra bolts above the water line on each side. it works well.

Good luck

 

[thomasiam]

Re: 12' porta bote mod project - progess report

Barato2- ya i'm a nuclear boy from NJ. home of the best supper sites in the nation

the water is actually coming from the side of the Bow not directly ahead like you described. it's the V below the bow that is kicking in water faster i go. only way i can think of is put a water shield on both side of the boat...... if you look at my last pic above the wake just kicks up inward.....

Mustard - i hear sailing is just crazy expensive to get into compare to motor boats. with anything else you start small and end up with a monster in the end. these boats are fun to modify and great starting boats....

 

[barato2]

Re: 12' porta bote mod project - progess report

Thomas--have you tried adjusting the motor trim? i trimmed mine up a bit and it made a world of difference in how the boat behaves, esp in bad seas. before, it was trying to bury the nose, which did hell on stability, and afterwards rides with the nose much higher and takes less water over the sides.

 

[thomasiam]

Re: 12' porta bote mod project - progess report

Thomas--have you tried adjusting the motor trim? i trimmed mine up a bit and it made a world of difference in how the boat behaves, esp in bad seas. before, it was trying to bury the nose, which did hell on stability, and afterwards rides with the nose much higher and takes less water over the sides.

i have to try that. thanks for the heads up.