Car topper to sneakbox Questions

Mark J.

Mark J.

Member
I have a 12 foot aluminium car topper that I am considering modifying into a sneakbox and am hoping for some advice/direction. I've wanted to build a boat for some time and have purchased Devlin plans and the Zack Taylor book but don't think I have time for a full build.

Reading back through the forum I've found reference to a few conversion type boats. My general idea is to rebuild the transom, rip out some of the bench seats and install bulkheads and decking - as well as fresh paint, flotation and odds and ends. The general dimensions of the boat are close to the widgeon and I was planning on doing some mock layouts with cardboard. Looking for a one man + dog boat, I hunt small inland water with runs from 1-5km from launching.



View attachment IMG_2903.JPG

I have a 70's evinrude 9.5 that works OK with the boat currently but may want to upgrade if this plan comes together.

Has anyone else modified a boat like this, or something similar? Any input on things to consider for a conversion project?

Thanks!
 
Hi Mark,

I have modified 3 different aluminum utility boats over the last 20 years. The first got a wooded deck with flip boards. The full write-up is in the original readers rigs (2 pages) off the site's main menu. This was the easiest modification, just needing wood working hand tools.

Next was a fairly heavy 14-ft Star Craft Seafarer v-hull. This write up was lost when the site was up dated 2006 - one of the problems of being so old. Here are a couple of pictures. It''s decked over with an aluminum deck w/ flip boards - kind of an aluminum copy of the wood deck. The deck was welded up for me by a fellow Connecticut hunter who saw my progress post here on the DHBP. Over time the wood flip boards rotted out, sitting on the aluminum deck they never fully dried out. They've been replaced with a composite material.

View attachment 14 ft underway2.JPG

View attachment Trimmeddeck.jpg



The most recent decked over a light 14-ft semi-V with lots of bells and whistles and a jet outboard. The deck was assembled with a combination of solid and pop rivets. These first two boats I left the seats in as well as their flotation since the decks are easily removable. This little jet boat I stripped out everything to a bare hull. Flotation is a combination of in the Bow & Stern with 2" off flotation under the deck to make sure she stays upright and has enough to climb on top of her in the cold water.

Have a great time modifying you car topper.
Scott
 
read my responses to Blakes post about looking for a sneak box. When I did mine, I only left the bow seat in, removed the others, and also cut the hull down, with the deck framing and new crowned deck theres plenty of strength left in the hull.
Read Zack Taylors chapter on the "Zack box", it covers a lot on these conversions and it's where I got the idea. As for flotation, 2-3 doz decoys under the deck will float it, if you're paranoid, put foam under the top deck, or leave the rear seat in. a 9.5 is plenty of motor for a 12' alu conversion
 
Mark~


I have done several conversions like this - but using 'glass hulls, not aluminum. Nevertheless, the process is essentially the same.


Although a different kind of vessel, I did cut down a 17-foot O'Day Ospray for gunning. Design and construction details are in:


https://stevenjaysanford.com/white-wing-2-man-scooter/


I probably posted about it here on duckboats.net, too.



In the pre-digital camera era I converted a Herter's car-topper into a 2-man (shooting side-by-side over the bow.) Once I removed the seats and transom, I was able to widen the beam out to about 60 inches.


View attachment Two-man Grassboat - SJS at speed.jpg



I over-built it somewhat. Now, I would make the bulkheads from half-inch and the decks from quarter-inch plywood.


Longitudinal framing members must be clear lumber but can be Doug-fir, Mahogany or even treated SYP. The most important framing member is the sheer clamp - that is attached to the inside of the gunwale and holds the sides of the hull to the deck. I have bedded mine in 3M 5200 with good success.


The other important lesson I learned (aka mistake I made) was to put 2 strakes on the hull - mostly to serve as runners. In practice, they simply grabbed the bottom when the tide ran out. Next time - if I needed to strengthen the bottom longitudinally, I would install a pair of stringers on the inside of the hull. I like a hull bottom that is smooth so I can horse it off a shoal when needed. If the hull skitters sideways in a turn I just ease up on the throttle.



I agree that a 9.5/9.9 should be plenty of power.


Sounds like a great project. As an aside, I've often wondered whether I should have made the old Herters into a one-man - so I could have retained its sweet tumblehome transom. I will follow your progress with great interest - and a bit of misty-eyed "what if?".....



All the best,


SJS





 
Thank you all for the input, I cleaned out some more space in the garage and will be picking up some cardboard tomorrow. The biggest piece for me will be getting a layout/design that makes sense and then making sure I do it all in the correct order.

More research to follow on what kind of fasteners to use in addition to 5200, but first things first.

Thanks again - hopefully more posts to follow soon.
 
Mark

That looks like the beginnings of a fun project. Can you tig weld? If you can the link below may be of interest to you. This guy modifies old aluminum boat and details his construction to a degree. Could be good for ideas.

https://www.instagram.com/fewmanboats/

Eric
 
While planning your cockpit layout set it up to shoot over stern with space for dog behind you inside cockpit. May require a Dodger over dog at least. Those little v hulls like to be wedged up into a bank crevice to not rock when you sit up to shoot. The other thing I would do is put in a flat floor maybe with some blue insulation foam board between it and hull. Make it removable in case at some point you have to rebuck bottom rivets at some point. By the way run some water inside hull first to make sure theres no leaks before starting anything if you haven,t already. Blue foam should help with flotation removal you,ll have with seat removal. Middle and back seats probably going to need to be removed. Top of deck/cockpit framing should stiffen hull to alleviate twisting. Make sure to design a crown into your deck. Battens and string line will become your friend!
 
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Roy~


I concur with your thoughts about shooting over the stern. My first 2 were designed to shoot over the bow - but time and tides showed me that trying to shove a squarish transom up into a ditch or other cover could be troublesome. It was not worth the effort for the little benefit of getting the motor out of the way.



All the best,


SJS

 
If gunning with a dog only sensible way to do it in my opinion. Plus you can simply let motor stick in bottom after wedging bow into crevice in marsh bank and your anchored unless tide comes to point motor down no longer holds. Never had an issue shooting over motor myself, others may differ. Does help of course to cover that motor in one way or the other .
 
Eric, no I can't tig (or any kind) of weld but know a few people with those skills.

Thanks for the link I will take a look. There seems to be a strong online community at tinboats.net with good resources, and a few popular youtube channels I have been trying to review.
 
Roy and Steve,

Yes my vision has me shooting over the stern with the dog behind me. I build my permanent duck blinds so the dog can mark the fall and want that to be the norm for hunting out of a boat as well. Secondarily I would like the option of flapper boards but we'll see how that develops.

I rebucked some rivets a couple years back, and before stashing the boat at the hunt club, backed a 10" section up with some of the dreaded flex seal. I will give it another water test before things get too serious.

Laid out a few options last night with scrap lumber and drop cloths and liked the direction things are going. I will have to put some thought into a cradle for construction, my garage and driveway are not close to level, but will want the option to roll the boat into the driveway for more working space in the 1 car garage.

Will attempt to put some ideas on paper and report back soon.

Thanks again everyone.
 
Steve, when I built layout blind for my Blackjack originally I bent 3/4" emt conduit like the doors on a field layout blind. Found out after a few uses it slowed the sit up to shoot response and converted the cordura door covering to your lap cover design with 3/8 " fiberglass rods laying across combing. Liked it much better. Am presently converting an old town 14' twin heron kayak to duck hunting mode with dog sitting behind me under dodger . Plan on going the lap cover route with that also.
 
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