How to make stronger transom for 12' PB?

[thomasiam]

Hi all,

I am thinking of getting a 9.9 HP gas engine for my 12? PB. Why spend the $$ for a 6hp if I can boost up the transom and get a 9.9.

Have anyone made their boat transom stronger to handle 9.9 hp motor and if so how? I?m thinking strong and light material to support the transom such as aluminum plate and C channels. Any thoughts?

 

[barato2]

Re: How to make stronger transom for 12' PB?

you mean a four stroke or 2 stroke? if it's a 2 stroke, you won't need to do much of anything. just replace that little dingleberry flap on the outside of transom with a hunk of exterior 3/4" ply the width of transom or nearly so. i've been using an 8hp on mine in severe duty, and even at one point had my 2 hp kicker on the butt simultaneously with the 8.

if you mean a 4 stroke, what kind of weight do you project? some of the more modern small 4 strokes are almost as light as a 2 stroke, but for some of the older ones that weigh 85-95 lbs, you will need to brace the transom. i have some pix saved of a fix that one guy (stepperbill) did to his transom using alum channel bolted to inside, but will have to look for em.

if you're upping the power, you may want to add longitudinal stiffening to the hullto raise the speed at which the hull begins the Dreaded Portabote Undulation

 

[thomasiam]

Re: How to make stronger transom for 12' PB?

you mean a four stroke or 2 stroke? if it's a 2 stroke, you won't need to do much of anything. just replace that little dingleberry flap on the outside of transom with a hunk of exterior 3/4" ply the width of transom or nearly so. i've been using an 8hp on mine in severe duty, and even at one point had my 2 hp kicker on the butt simultaneously with the 8.

if you mean a 4 stroke, what kind of weight do you project? some of the more modern small 4 strokes are almost as light as a 2 stroke, but for some of the older ones that weigh 85-95 lbs, you will need to brace the transom. i have some pix saved of a fix that one guy (stepperbill) did to his transom using alum channel bolted to inside, but will have to look for em.

if you're upping the power, you may want to add longitudinal stiffening to the hullto raise the speed at which the hull begins the Dreaded Portabote Undulation

thanks for the info.
i am looking at 9.9 HP 4 stroke Nissan. i think the weight is 81.5 lbs. it would be great if you can send me the stepperbill's plan if you have it around. what is PB undulation? sorry but i'm new at this....

 

[Wakko]

Re: How to make stronger transom for 12' PB?

81 pounds? :scared:

 

[barato2]

Re: How to make stronger transom for 12' PB?

Thomas---i was referring to the undulation that travels through the hull and forms the usual "de facto" limit on how fast you can shove the things. when you get up on plane enough, the middle of the boat bows downward, away from the center support for the middle seat, and the boat gets squirrelly. on mine, this usually starts about 11-13 mph. adjusting the trim angle on your motor (moving the pin) sometimes helps....helped a lot with mine. i'll find and post what Mr Bill did....great ideas which i may adapt and riff off of

81 lbs is pretty heavy....you''ll definitely want some serious bracing. altho it's no more than my two motors together weigh, and the transom didn't come off the boat with both mounted simultaneously

 

[thomasiam]

Re: How to make stronger transom for 12' PB?

Thomas---i was referring to the undulation that travels through the hull and forms the usual "de facto" limit on how fast you can shove the things. when you get up on plane enough, the middle of the boat bows downward, away from the center support for the middle seat, and the boat gets squirrelly. on mine, this usually starts about 11-13 mph. adjusting the trim angle on your motor (moving the pin) sometimes helps....helped a lot with mine. i'll find and post what Mr Bill did....great ideas which i may adapt and riff off of

81 lbs is pretty heavy....you''ll definitely want some serious bracing. altho it's no more than my two motors together weigh, and the transom didn't come off the boat with both mounted simultaneously

thanks for the info. please share mr. bill's idea.

 

[Wakko]

Re: How to make stronger transom for 12' PB?

The top lip of my plastic transom smashed when the oversize mounting discs on the bolts crushed it when I got sideswiped by a 42 foot tidal wave at the local ski lake Sunday. I need to bolster this baby up or build a replacement, so any information ASAP would be great. Monday's Labor Day and a great lake day.

 

[barato2]

Re: How to make stronger transom for 12' PB?

gents---here are pix of the mod.s Stepperbill made to his transom to beef it for a huge motor....i think he's running a 15 hp 4-stroke. i like his ideas and will likely emulate them if i want to use my 10hp Honda on it

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Jakko, i wonder if just adding two pieces of alum L-channel stuck together to form a "U" over your transom might be enough to get you going for the weekend?

 

[Wakko]

Re: How to make stronger transom for 12' PB?

Yeah, I bet it would. The transom is strong enough for my little 7.5 anemia pump, it's just not shaped right. Well, especially with the cracks on the top. Waht's with his floor in that pic?

 

[thomasiam]

Re: How to make stronger transom for 12' PB?

this is totally awesome. thanks a million. i found guys that will sell me 1/2" thick aluminum rods/angle so on. Online Metal Store | Small Quantity Metal Orders | Metal Cutting, Sales & Shipping | Buy Steel, Aluminum, Copper, Brass, Stainless | Metal Product Guides at OnlineMetals.com

will build this and post my boat. thanks guys!!!!!!

 

[barato2]

Re: How to make stronger transom for 12' PB?

Thomas, 1/2" thick is gross overkill and will weigh a lot more. 1/8" thick is enough.

Wakko---he also installed longitudinal stringers (1/2" U-channel inside and out, with hull sandwiced between) to reduce the undulation and to up the speed at which it starts. he sez it's been very effective and his top speed is well over 20mph....calls it a "Sportaboat". i may try this but need to be sure since it involves drilling lots of holes below water line.

 

[thomasiam]

Re: How to make stronger transom for 12' PB?

Thomas, 1/2" thick is gross overkill and will weigh a lot more. 1/8" thick is enough.

Wakko---he also installed longitudinal stringers (1/2" U-channel inside and out, with hull sandwiced between) to reduce the undulation and to up the speed at which it starts. he sez it's been very effective and his top speed is well over 20mph....calls it a "Sportaboat". i may try this but need to be sure since it involves drilling lots of holes below water line.

do you know how long of a longitudinal stringers he use? all the way to the front?
i was also thinking about foaming the inside of the transom to give it a extra stiffness.

it's funny by the time I'm done with this add-ons i should just buy a regular boat.

thanks

 

[barato2]

Re: How to make stronger transom for 12' PB?

not sure but i think they went most of the way forward.

no Q this thing has some "issues" you wouldn't have with, say a 12' aluminum boat. but it also offers benefits they can't.....far more seaworthy, IMHO, than equiv size tinnie, and unsinkable and no "booming" from the alum hull. i HAVE several regular boats (3 tinnies, one fiberglass sailboat, and several inflatables), and still find i use the PB more than the others.....my 4WD truck has gotten up to almost 24 mpg with it on top of camper shell. i AM thinking of getting a trailer so i can set the 'bote up at home for local trips.

 

[thomasiam]

Re: How to make stronger transom for 12' PB?

not sure but i think they went most of the way forward.

no Q this thing has some "issues" you wouldn't have with, say a 12' aluminum boat. but it also offers benefits they can't.....far more seaworthy, IMHO, than equiv size tinnie, and unsinkable and no "booming" from the alum hull. i HAVE several regular boats (3 tinnies, one fiberglass sailboat, and several inflatables), and still find i use the PB more than the others.....my 4WD truck has gotten up to almost 24 mpg with it on top of camper shell. i AM thinking of getting a trailer so i can set the 'bote up at home for local trips.

that's cool. i already got a trailer for the PB. just simpler and saves time if the place has a ramp. i have few more extras i am going to setup on my boat so it should make it more stable since im going to add a fish finer, toiling motor and stabilizer (left over from canoe) for my heavier friends join me fishing standing up. it's going to be a monster. hope it wont be a Titanic on after the modifications.

 

[barato2]

Re: How to make stronger transom for 12' PB?

if the stabilizer is one of those "outrigger" type arrangements, you may find you don't need it. trolling motor should be easy, just be sure to get one with short enough shaft....most are waaaaay too long for comfortable use on PB.

here's what i did to mount transducer on mine.....a 3/4" ply board on outside of transom, bolted through it w/ two 1/4" SS bolts well above water line (and holes spaced so i can attach rod holder on inside of transom).

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board is long enough to reach down to where you'd mount transducer. not 100% happy with the PVC-pipe arrangement to mount transducer, but it lets me raise it for beaching. i got mine as a kit from Cab~~~'s with the bag you see in pic, small AGM battery, and charger.....it's one of the Eagle "cuda" units with sonar and GPS, and IT SURVIVED BEING SUBMERGED IN SALT WATER FOR 3 HOURS ONCE. did i mention that i'm impressed with its durability? esp offshore in the PB, where i don't take anything along that can't get drowned. its big limitation is power; i can't get readings much below 450'

 

[thomasiam]

Re: How to make stronger transom for 12' PB?

borato 2 - that boat is totally stocked!!!! i see the cross support via plywood seat. nice....

as long as Fish finder goes i am using this setup.

it's totally adjustable and secure on to my PB.

it seems like so many of us are having this transom issue why don't they just make the transom out of better and strong material.... if you buy a new PB it's not cheap so they should really think this over.. i kind like because i am learning so much about Boat 101 and how things work due to these upgrades....


i should get my 9.8 HP outboard and aluminum supports today. will post once i get it all together. thanks again. you are in the west coast? Nice yellow tail in your photos.

thomas

 

[barato2]

Re: How to make stronger transom for 12' PB?

you may have seen the response from "portabot" to your transom comments. that was Sandy Kay, the CEO of the company. as one of the portabote's strongest advocates, i figured i should give him an earful, and did, in response to his claim that somehow your transom problems (and those of everyone else who's complained about the plastic trans) were due to something you did wrong rather than poor design.

i actually live in the desert, far from any ocean, but travel regularly to San Carlos, Sonora, Mexico for my dose of salt water. that's where the yellowtail and sailfish pix are from. thanks.