Building a small boat with an enclosed cabin

Designs for inboard or outboard power

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Fish Mag
Posts: 4
Joined: Wed Jan 13, 2016 3:14 pm
Location: Sandpoint Idaho

Building a small boat with an enclosed cabin

Postby Fish Mag » Wed Jan 13, 2016 3:55 pm

Hi everyone. My name is Vince. I live in North Idaho. I'm new to this site and new to the thought of building my own boat. I know what i would like to build but am not finding any plans. I would like to build a 16' skiff with an enclosed hard top for those chilly days with a little heat. Not to ruff out yet need a boat that can handle the ruff stuff if caught out in it. I look at all the plans but don't want to modify anything and make the boat unsafe. I've been looking at the Glen L center console design and like the looks. I don't need a lot of bow space. I want a larger cock pit for fishing. When i look at the boats i worry about making them bow heavy. Any thoughts, ideas or know of any plans that might fit my description? P.S. I don't want to put a canvas enclosure on it. Thanks for any input you may have.

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Joined: Sat Jan 17, 2009 1:37 am
Location: Inverary, Ontario - Cuddy Sport (modified)

Re: Building a small boat with an enclosed cabin

Postby galamb » Wed Jan 13, 2016 5:19 pm

Even on a 16 footer you can move some "stuff" around to keep things balanced around the center of buoyancy.

Depending on what material you use, even an extensive cabin may not add significant weight. In a center console simply moving the console back a foot would shift some significant weight "rearward".

All the Glen-L plans show the center of buoyancy (as designed). From that you just treat the hull like a teeter-tooter. If you put 50 extra pounds 2 feet forward of that (CB) then putting 50 extra pounds 2 feet to the rear of that point will keep things in balance - and not giving you the correct math here, but you might only have to put 20 extra pounds 4 feet back of the CB to offset the 50 pounds 2 feet forward (if you get where I'm going here).

One thing you have to consider a little more (since balance can often be easily maintained) is whether your plan would make the boat "tippy". There is vertical limitations based on the beam of the boat - if you go "higher" than is feasible compared to the width you are working with you could end up being "top heavy" - again, I can't give you the math on that but it most certainly exists. Again, that could be offset somewhat by building a heavier hull (which would lower the overall center of gravity - more math stuff :) ).

While that would increase your stability overall it would also cost you more gas/possibly greater horsepower to push that heavier hull.

On my Cuddy Sport I indulged a bit (along the lines you are thinking) - it was designed as a 24' walk-around cuddy. I stretched it to 26' (25' 11" - the plans give you some options to do so) and instead of an essentially open cock-pick I added an "Alaska cabin" (I boat in Canada - the enclosure significantly expands the boating season which is short to start with).

The effect of my modifications took the (as designed) 1400 lb unrigged hull and turned into an 1800 pound unrigged hull (almost 30% heavier than designed) - and that extra weight does cost me more to push around, but made the boat infinitely more "usable" so for me the trade-off was worth it.

My cabin is essentially constructed of 1x2 and 1x3 framing (douglas fir) covered with 1/4" (6mm) okoume sheet material and a 4oz fiberglass cloth/epoxy which was a good balance of strength and weight when I planned the build. That combined with a great number of windows in the cabin (marine glass for the "windshield" portion and 3 mm Lexan for the side panels) kept the weight reasonable.

Also, with a bigger boat I had the ability to place to 40 gallon belly (gas) tanks under the floor immediately below the (cabin) straddling the CB - that more than offset the "vertical weight" of the cabin.

For all my blabbing, my point is, with some thought and (a lot of on-line reading about boat engineering) you can do most anything you want "within reason".

Yes, Plywood is "real" wood :)

A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

Fish Mag
Posts: 4
Joined: Wed Jan 13, 2016 3:14 pm
Location: Sandpoint Idaho

Re: Building a small boat with an enclosed cabin

Postby Fish Mag » Fri Jan 15, 2016 12:59 pm

GLAMB. Thank you for your input. Low center of gravity was on my mind also and things that you said got me thinking of battery placement, fuel tank placement, etc. After writing this i found dory cabins listed and that gave me a few options for the design. An Alaskan bulk head is what i want because i enjoy the winter fishing. I just need to be careful about over thinking this project, i don't want to bite off more than i can chew for my first boat yet safety is my first concern, our lake can get real rough real quick. I have a 28' bayliner but i still love a smaller boat for shore line trolling on those calmer days.Thanks again for your input.

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