A couple of mods to an OLD 12'er

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finstr

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I don't have an original pic but this 12' tinny was in rough shape. Picked it up for $200 last year. Was covered with 5 coats of blue tremclad. 4 patches on the bottom with a ton of silicone. I redid the transom and added 5" to accomodate the long shaft 5hp Honda which was too under powered so I bought an 8 short shaft and ended up cutting the 5" back out.
9uroFE52.jpeg


Painted the sides with a metallic green Chrysler colour. Interior with etch primer and texture trunk paint. Trailer was $150 with a bad axle so I built an axle out of a Corolla
WFIwgwvv.jpeg
 
Lookin' good!

If you haven't already, get rid of those patches using silicone. Most silicone goops cure by the addition of an acid-base that will corrode aluminum.
 
DaleH said:
Lookin' good!

If you haven't already, get rid of those patches using silicone. Most silicone goops cure by the addition of an acid-base that will corrode aluminum.
Click to expand...

First thing I did! Lol
Get this; a small puncture in the hull maybe 1/4" long. So the PO drills 12 holes for 1/8" rivets and uses steel patch with silicone on both sides. Then puts larger aluminum patch over top with 12 more rivets and silicone. The steel had rusted and corroded the aluminum patch. Add 20lbs of Tremclad to hull, well you get the idea.
So for each small puncture there was no less than 24 holes drilled! :roflmao: insane.

I ground the mess off clean and used a Norton epoxy for adhering body panels. Its bond is much sronger than the aluminum and will not tear. Then I put a small smear of Shoe Goo around the perimeter to seal it and smooth the edges.
 
Nice work!
I've been thinking of doing trim tabs on a 1974 Starcraft 14 1/2 ft Holiday because its a big heavy closed bow design rated for 55 hp and the reservoir I want to use it on has low hp limits of 20 hp two stroke or 25 hp four stroke. Currently there's a 1986 20 hp Evinrude short shaft on it. Which weighs about 86 lbs (but its not working so I may ADD weight by replacing with a used 25 four stroke for better slow speed salmon/trout trolling.

My questions please:
(1) how much did the trim tabs improve top speed and cruising speed? Its a 10 mile long reservoir, long and narrow, and I'd like to be able to max out speed.
(2) for all members: any links to prefabricated small trim tabs I could buy suitable for a 14 tinny? I could get em on but couldn't fabricate my own. I found some for small boats on Cabelas but they're adjustable so I wonder if anyone has had good or bad experience with them, e.g. do they fail to hold the desired angle when in use?
(3) any thoughts on pros and con's of weight vs. top speed and trolling performance of the current 20 hp two stroke (maybe $500 to fix) vs. Buying a used 25 hp four stroke for about $1500 to $2k which would weigh about 130 lbs? Regarding weight vs power Tradeoffs as it affects boat speed?

I'm new here and really admire all the expertise and ingenuity. Thanks very much to all!

Sent from my SM-N900V using Tapatalk
 
onthewatersx3 said:
Nice work!
I've been thinking of doing trim tabs on a 1974 Starcraft 14 1/2 ft Holiday because its a big heavy closed bow design rated for 55 hp and the reservoir I want to use it on has low hp limits of 20 hp two stroke or 25 hp four stroke. Currently there's a 1986 20 hp Evinrude short shaft on it. Which weighs about 86 lbs (but its not working so I may ADD weight by replacing with a used 25 four stroke for better slow speed salmon/trout trolling.

My questions please:
(1) how much did the trim tabs improve top speed and cruising speed? Its a 10 mile long reservoir, long and narrow, and I'd like to be able to max out speed.
(2) for all members: any links to prefabricated small trim tabs I could buy suitable for a 14 tinny? I could get em on but couldn't fabricate my own. I found some for small boats on Cabelas but they're adjustable so I wonder if anyone has had good or bad experience with them, e.g. do they fail to hold the desired angle when in use?
(3) any thoughts on pros and con's of weight vs. top speed and trolling performance of the current 20 hp two stroke (maybe $500 to fix) vs. Buying a used 25 hp four stroke for about $1500 to $2k which would weigh about 130 lbs? Regarding weight vs power Tradeoffs as it affects boat speed?

I'm new here and really admire all the expertise and ingenuity. Thanks very much to all!

Sent from my SM-N900V using Tapatalk
Click to expand...

I had a chance to try out the trim tabs and they do work although limited. I think because my top speed with the 8hp isn't very fast they don't have the uplift they could have. Plus I've added a fair bit of weight to the boat with a large battery,trolling motor,seats,shelf etc.
I have drilled a few holes for adjustments and will continue to play with them. I'm also considering putting pneumatic cylinders on them so I can adjust while at speed. It's such a tiny boat but the physics are the same I think.
I can't comment on the 25 hp 4 stroke other than I really like the way they idle and how quiet and clean they are.
 
I've spent a lot of time in 12 foot tinnies and agree you have a weight to power issue. I've had more luck moving the battery and the gas tank into the bow, and setting the motor trim bracket in the 2nd hole from closest to transom. Otherwise the bow stays too high and the stern stays dug in and you don't get up on plane. You might consider longer trim tabs and/or trying a bit of down angle so they lift more, though who knows if the added drag will defeat the purpose. Good luck and thanks.

Sent from my SM-N900V using Tapatalk
 

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