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Cajun_Ag
11-11-2009, 11:48 AM
I'm in the process of designing a mini 12X(6.5-7')w/ 50-70hp 2 stroke. I plan to run the boat in East Texas so it will see some stumps while running, fishing and some light bowfishing. Do you guys think a 1/4" plywood hull glassed on both sides will work for this purpose. Also what do you guys recommend as a stringer material since it will contact water by way of the holes attaching the rigging. Does steel Flex add much strength to a hull or is it just for making the bottom slick. I'm also considering some very thin (1/8-1/4") poly, but will probably run it until I determine if it's needed.
Thanks in advance any help is appreciated

Duane Scarborough
11-11-2009, 07:02 PM
Cajun_Ag ,

I'm certainly not an expert on this, but I'll throw in my 2 cents worth. ;)

Please keep in mind that my opinion on this may be worth exactly 2 cents. :o But you asked. ;garfield;

Many years ago, there were hundreds of boats built the way you describe, but with much larger engines. Hardly anyone builds them that way anymore, and there are reasons for that.

They can get heavy pretty quick, and are not as strong (on a weight to strength basis) as a properly built laid-up fiberglass hull, or an aluminum hull.

Though it may seem like a very cost effective way to get a hull, the material costs will add up really quick, especially if you are paying retail prices.

Designing your own hull may sound like a good idea at first.... but considering that the guys who've been doing this for a long time have spent years getting it right, and wasted several thousands of dollars in the process, the odds of your first self designed boat turning out a winner is slim.

For these reasons, I think that you'd be better off in the long run to start out with a proven hull, New or Used, from a reputable builder.

I went through some of these questions when I was starting on my build. I wanted to build my own Mini Airboat. But, after a lot of thought, I chose to buy a proven hull, and then build the rigging myself, instead of starting totally from scratch. I'd highly recommend that you do the same.

As for the steel flex, and other painted on coatings, as far as I understand, they are only to help make the hull slick. If you know that you are going to abuse the hull, polymer is a good idea, but it also comes with a need for much more HP, because of the added weight...


Please keep us posted on what you decide to do.

Thanks,

Duane

Wildfowl
11-11-2009, 07:44 PM
Hi Cajun,

Kind of like Duane said the wood hulls just get heavy. They would work ok strength wise but the weight will be tough to overcome. You get a crack and a leak and your done for with the wood soaking up the water.

I have seen a few of the old wood boats (1950's-60's) with big engines struggle compared to the glass and now aluminum hulls. Have seen at least a dozen over the years (70's to 90's) come out to the rive and make a run and they don't come back for one reason or the other.

The hull for a mini is going to be your biggest challenge. Has to be the right width and light. I think the new hulls are very reasonable if you add up what the glass and all the work will cost you on your own. The only reason I went with a used one was I lucked out and found one on the Island. And I do mean lucked out. ;garfield; I think I did anyway... :mrgreen:

A 1/4" plywood will get you the strength with a layer of woven matt/cloth or two to rap it up. But if you go that far, imho, you just as well use the wood boat frame for a mold and add a couple more layers of woven mat to the two you would have anyway and make a glass hull. Funny how that works. Well not funny but interesting yes? There is a lot more involved like flex and stiffness characteristics as well.

If wood was the way to go and it had something to offer I think we would see a lot more wood airboats on the water. Wood does make a good V hull and sail boat but that is a whole different design.

Would love to see you pull out a good one and have some success. I'm sure everyone here is willing to help if you give it a go.

By the way my opinion is availble at a discounted rate of ... well... lets see... less than Duanes anyway :D He's older. ;stir; :mrgreen: Mine might be worth just what you paid for it. :lol:

Duane Scarborough
11-11-2009, 08:02 PM
Mike,

You just had to discount the rate, didn't you? ;rasta; I was in line to get rich, and you blew it for me.....

You brought up a good point about the water absorption.... just ask Buster. Even as light as foam is, it's a water magnet.

Duane

Sandman
11-12-2009, 06:18 AM
I was thinking of doing a wood hull and at times I still think of it.. but these two are completely correct...
Wooden hulls are a constant maintenance issue.. think of the cedar strip canoe as an example, many hours building one with a similar cost outcome for a decent glass canoe. Then constant maintenance to keep it in tip top condition. Every ding will let in water meaning that re-sealing the boat on a yearly basis becomes the reality of owning one.
I was also thinking of doing a foam core glass boat. In my opinion foam makes a better material than wood for lightness. Sandwiched glass covered foam is extremely strong and allot of major boat manufacturers use this process for boats that are intended to avoid obstacles. Surf boards are glass over foam, they are extremely stiff and durable.. but never intended to run on mud or rocks.
I still favor the foam design but if I do one it will have the hull thickness to survive impacts. Eventually the foam will break down and absorb water :cry: Once that happens.. the foam would need to be removed (labor intensive) and the hull stiffened or the foam replaced.
Cost plus labor = a less enjoyable boat.
So, my plan is to save, buy a hull intended for airboating.

Cajun_Ag
11-12-2009, 11:39 AM
OK so no plywood. I will say that I am somewhat determined to build my own boat, for the experience more than anything else. So I found this C-Flex stuff and although it is intended for large boats and poly resin, there have been positive results with epoxy and cloth sandwiching it. I also know a local guy who can built an aluminum hull for me as a last resort I just need to check the costs.

Wildfowl
11-12-2009, 12:12 PM
That sounds like an idea... glad the reply(s) didnt slow down your determination.

Looking forward to seeing your progress.

Cajun_Ag
11-17-2009, 11:00 AM
This is my hull design. I located a 800cc engine for cheap. It's more HP (~100) than I was looking for, but I've never heard anyone say they wish they had less. Ya it's also a gas hog. I work for an O&G company so I look at as job security. The design 12.5' long and 6.5' before the upturn. Draft is 3.5" w/ 850# displacement

Papee
11-17-2009, 05:59 PM
Looks like a winner, mine was only 6'8" of flat bottom when it was at 16 ft in total length with a 5' wide bottom and it worked pretty well.

Duane Scarborough
11-17-2009, 06:17 PM
Cajun_Ag,

It looks pretty good from here. :D

If you're up to building a hull from scratch, then I'm sure up to seeing how you do it. And your build photos. ;thumb;

We'll be rooting for you.... 8-)

Duane

Wildfowl
11-17-2009, 06:34 PM
Very nice! ;thumb;