Help with an unkown 12 ft aluminum vhull

[Alec Ricard]

Hello all I'm a newbie when it comes to aluminum boats and their repairs and modifications. I have a 12 ft aluminum v hull and I'm looking for helpful info. What's the simplist way of removing the middle bench and putting a flat floor in? not a mini bass boat setup as I like to keep center of gravity as low as possible in the boat. There's a slow leak from a couple middle bench rivets that I have brazing rods and silicone to seal it up. Can I use spray primer & paint and some clear coat for the hull? I have a great 62 evinrude 3.5 HP 2 stroke runs like a dream is this motor capable of safely traversing rivers with medium current? Are float pods beneficial? I have damaged strakes but they still hold shape and should do they're job but have a couple holes are they worth repairing? Or should they be replaced? Or is it not really of concern? Any extra info would be greatly appreciated I'm restricted in budget and I favour simplicity in design so please keep that in mind. I can provide specific pictures for analysis.

 

[Ray Clark]

Regarding bench removal, I recently posted this in another thread on the board about removing benches in aluminum boats:

"If there is an existing bench in that boat: My concern about just cutting a pass-through an existing bench is altering the lateral strength of the hull. I think those benches provide a fair amount of rigidity to the hull. I've considered doing that to my V-hull tinny, but the structural integrity risk stopped me. I converted my middle bench into a battery box."

My engineer son-in-law shares my concern, and he has some experience with boats of varying structural integrity. Rigidity removed from the hull in the center needs to be at least partially replaced in my view.

As for sealing rivets with silicone, I've read here and in a number of other places that silicone is not really suitable for sealing boat rivets below the waterline. I don't have first hand experience on that; maybe others will chime in.

Regarding boating on rivers with a 3.5 HP motor: I wouldn't do it. You said the river is of medium current. How I might test that motor safely for use on the river: Take the boat and motor to a lake and determine your top speed with the boat loaded at max weight. Compare that top speed with the speed of the river current. The boat has to be faster than the current, or you can't just control it. If it was me, I'd want to be faster than the current by 5 mph or more. You need to be able to go upstream at a reasonable rate of speed. Additionally, river conditions can change quickly. You don't want to be underpowered on a river.

 

[Alec Ricard]

Ok I was thinking in lieu of the center bench was a 2x4 spanning the width of the bottom and other 2x4's at a 45 degree angle from the gunnels to the bottom 2x4 and I was thinking of doing 2 that way the outside pressure would push the angled 2x4 down into the horizontal 2x4 spanning the bottom I have a crude sketch I'll add to this to give you an idea the view is from the transom and the yellow is the 2x4's

 

[airshot]

Some folks just cut out the center of the middle bench seat to make a pass thru area without having to step up and over....this retains some structural integrity in that area. NO silicone under the water line, it wont hold or last. There are many quality sealants that can be used that are made for below the waterline. If your serious about stopping leaks, clean the interior then coat with gluvit sealer and paint. Make sure any wood on the transom is solid, if not replace it with plywood or your motor might go for a swim...and they dont float !!
As for your 3 hp motor, how fast is the current ?? Big question there but it is important!! I have a 2.2 hp on my 12' jon boat and that works OK in a 5 mph current but not any more than that..

 

[Alec Ricard]

Some folks just cut out the center of the middle bench seat to make a pass thru area without having to step up and over....this retains some structural integrity in that area. NO silicone under the water line, it wont hold or last. There are many quality sealants that can be used that are made for below the waterline. If your serious about stopping leaks, clean the interior then coat with gluvit sealer and paint. Make sure any wood on the transom is solid, if not replace it with plywood or your motor might go for a swim...and they dont float !!
As for your 3 hp motor, how fast is the current ?? Big question there but it is important!! I have a 2.2 hp on my 12' jon boat and that works OK in a 5 mph current but not any more than that..

The 3.5 gets its current weight from the photo to 8mph up to ten in ideal conditions with me in it and im 280 IBS

 

[LaqueRatt]

Just my opinion and I'm a bit of a noob too, but I'd get a bigger motor. That size will surely move the boat, but if it's like my 2 14 footers it will never get on plane with anything smaller than maybe a 9.9HP. You'll have to creep along at trolling speed or have the nose so far up in the air you'll not be able to see where you're going. Better than rowing, but not enough power to do much more than putt-putt along. OK for a pond maybe, but not a river or a decent sized lake. For my boats a 14 HP needs to be nearly wide open to get on plane. The 18 HP will throttle down to about 3/4 and maintain plane.

 

[Alec Ricard]

I hear what you're saying but I think people underate these small HP motors considering I've used a 2.5hp on a ten foot wooden boat in saltwater I know it's two different environments but if it can handle the sea and travel a moderate speed even with wind then I figured a 3.5 would be ok for the prairie pot hole lakes around me not to mention the price of motors here in Canada currently 5hp motors going for like 2 grand. I guess I should've added I'm not looking for speed just to get to the fish and casual sails with the kids. Even a weeken trip down the river and back.

 

[LaqueRatt]

Again, just a noobish opinion, but don't you think a wood boat is a lot heavier than aluminum? That heavy wood boat may not nose up like an aluminum boat. Another factor is my boats are way stern heavy. If you don't have a 70 lb battery in the back and 60 lbs of gas yours might behave better than mine. Man I'm glad I don't live by you. A couple months ago I picked up a running 6 HP Johnson for $75. Way too small for my boats though so I'll probably sell it. It was just too nice to pass up.

 

[Weldorthemagnificent]

Removing a bench can cause a hull to flex more than it was meant to. That being said, if all you ever do is travel at displacement speeds (not planing) and 6 HP or under, I say go for it. Not pounding through whitecaps. If rivets are leaking, rebuck them. You can get a tool for this but all I do is get a buddy to hold a sledge on the outside and whack the rivet from the inside. Sometimes hit em again with a center punch to swell it up.

 

[Alec Ricard]

Beautifully simple thank you. Am I replacing the rivets and then hammering them? Or just deforming the existing rivets to expand and so it doesn't leak any more?

 

[Sea Antsy]

... sounds like a plan... be aware that all rivets are not the same size or SHAPE... then there are the pop rivets-open or closed head...
be careful using a CENTER PUNCH...for some rivets it may be the best tool, but..
your objective is to PUSH-DRIVE-FORCE the material of the rivet outward to the sides of the hole and better fill in the gaps
making a mushroom of the head.. on some size/shape rivets the centerpunch might be too sharp-pointed to mushroom properly
consider having a few different size philips screw hex bits on hand to mushroom out the bigger rivet heads..
good luck

 

[uncndl1]

Hello all I'm a newbie when it comes to aluminum boats and their repairs and modifications. I have a 12 ft aluminum v hull and I'm looking for helpful info. What's the simplist way of removing the middle bench and putting a flat floor in? not a mini bass boat setup as I like to keep center of gravity as low as possible in the boat. There's a slow leak from a couple middle bench rivets that I have brazing rods and silicone to seal it up. Can I use spray primer & paint and some clear coat for the hull? I have a great 62 evinrude 3.5 HP 2 stroke runs like a dream is this motor capable of safely traversing rivers with medium current? Are float pods beneficial? I have damaged strakes but they still hold shape and should do they're job but have a couple holes are they worth repairing? Or should they be replaced? Or is it not really of concern? Any extra info would be greatly appreciated I'm restricted in budget and I favour simplicity in design so please keep that in mind. I can provide specific pictures for analysis.

People above have answered most of your questions.
I used zinc chromate primer from hardware store after cleaning my old aluminum boat.

Here’s a link to my project:
https://www.tinboats.net/threads/wards-sea-king-aluminum-boat.39891/

 

[Fishingman48]

Somewhat of newbie here as well been here a couple yrs. and still learning, I guess we all never stop learning. Even the Pro's find new way's and pass em' on! Yeah I seen yah talkin about no bench in center of boat / I have a troller 14' w/ 20hp merc bow is close with storage comp. & putting in a seat / now my stern is " one bench" a large live well is part of the bench if not 80%.
Wood blocked underneath to help with my weight and weight of live well when in use . Now point I am getting at is I believe the bow being closed off and the only bench being in stern tightens up center of body where you don't have that fixability of in and out or rolling of side walls of boat . I am just saying if you want to remove the bench in center and open center of body you would have to compensate for it some place else! Like the bow with a platform which would grab the side walls & pull them in "depending on size of your front platform" if you so choose to install one ? This allows for walking around within center area & use of pole seats with base's built into your floor which can be removed & turn into a "multi use floor area".The pic ture shown is a "86 on 87 the side walls are thinner than 86 & allows more area for movement walls are 60% filled with pour foam other 40% is storage / pole's, ropes, anchors, rear bench as stated live well & bow is storage . this hold's a 20 hp merc. Calls for I think was 25 hp. rear bench can be modif. as you wish SEATING FOR SHORT POLE VERSION OR BENCH CLAMP TYPE if your taking out center benches and putting in front platform the side basically in a way become your center benches but not in center used for buoyance & storage and strength side as drawn in and bolted to platform & live well bench also draws in side's when bolted into place. Just an idea for you .
I also seen you were talking about tightening up rivets ? Yeah the sledge on one side & two pounder on the other, I remember my father and I doin this as he had a few slight leaks crambed in some seam seal , he would heat it up a bit and allow it to seep in and cool said it worked better as got into area & filled it in instead of covering area and while it was warm I would be on one side he would be on other making sure to mushroom heads,& if they split he removed and installed a new one . & if your the guy on the inside of boat wear ear plug's!!!!!!!
I do hope my 2 cents helped ! & bye the way welcome!