The game is afoot

prop protection

Or old school as per photo. However like the idea of the duct. Reduces speed on the top end a little but increases driving thrust on the low to mid range while protecting the prop. Another option jet drive ?

 

sounds like another idea bites the dust

oh well
speaking of ideas that are biting the dust I got a price back on seedlac, about $2500 for enough to make 30 gallons at 9# pr/g

If I remember your thinking I can get the epoxy for half that, and its generally superior in all aspects except in environmental and health considerations. Gotta wonder if there is a non petroleum based epoxy. I noticed titebond 3 claims a type 1 status but we kinda went over that and its not all that stable, although Tad did mention a guy who built his hulls out of alphaliphatics and then skinned them in epoxy and cloth.


http://www.boatdesign.net/forums/wooden-boat-building-restoration/titebond-iii-testing-27019.html

 

Boston Re. epoxy, have you built up a sensitivity to it over the years. Man thats the cadillac lanimating glue and hull/glassfiber coating -Do her inside and out. Have you thought about strip planking-- The guys here at Covey Island Boat Works specialize in it.-- Very strong requires less internal framing. ---Geo.

 

I was kinda thinking almost no internal framing, and ya I'm kinda stuck with epoxy, har har har

 

If your thinking of something with no enternal framing I hope you have to blow it up. Hot air is best.

 

Boston, Strip plank requires possibly the least amount. I'm sure the guys on the forum can advise you on how much and where but when the hull is removed from the building moulds it is already very stiff with no internal framing and then would be the time to epoxy coat her inside. If I were to build in wood (no chines)it would be my choice of construction. Anyhow will stand by on your progress, I'm a builder not a designer per say and if I can see helpful input I'll jump in. Got this keel/ballast design thing i'm into now, coming along real well with the forum help, just a couple more queries to put to bed and i'll be using strip planking to make up the male mould to glass up the shell for it. Just think if we didn't have boats to build what wonderful trouble we could get into--Geo.

 

trust me I get into enough trouble as it is
oh and no I don't think I have any issues with epoxy its just I was hoping for some alternative

cheers
B

 

Just out of curiosity how many of you readers/contributors would recommend strip planking over cold molding ?

 

Cold molding alone, requires a very closely spaced, time consuming to build jig. Once the first couple of veneers go down, then the hull becomes firm enough to take the weight of a man standing on a buttock with a staple gun.

A better alternative and a common build method is a strip planked core with a veneer exterior. You can orient the veneer so it looks like a carvel hull if desired, though usually it's just applied on a bias, so it's easier to fit. The jig is much simpler to make, using much less material. The strips can be quite inexpensive and any trained monkey can install them over the jig. The veneers need to be fitted, but if a painted finish is desired, you don't have to be neat as wood butcher's friend will rescue any major screw ups. A well designed strip/molded hull requires no internal framing in the conventional manner. Perimeter cleats for berths, counter tops, cabinets and other internal furniture will usually provide sufficient stiffness, possably a bulkhead or two. The result is a monocoque structure, devoid of the usual timbers and typically lighter by a considerable margin as well.

 

hmmm the stations are every 3' and I was thinking i'd have to develop some take offs from the lofting to decrease that for cold molding, not sure how fair anything would turn out on 3' stations

interesting stuff Par
trained monkey eh, watch me screw it up.

Getting the dust collection system set up and just organizing for the moment.

this suggestion has an interesting side effect of being able to utilize a lower grade of lumber on the strips and simply cut out defects and scarf together the worthwhile stuff. I see where it would use less wood in the end. You end up with a thicker hull though. Not as light but still pretty light and almost as stiff.

I wonder if I could get away with TB-3 on the strips and go with epoxy on the outside kinda like the guy Tad mentioned. I'm thinking red ceder on these strips, that stuff soaks up a lot of glue and isn't all that strong anyway.

I could go Poplar oh that would cause a ruckus

a previous quote concerning alternatives to epoxy in this kind of construction

so I'm kinda curious as to how Guzzwell got away with using Elmers glue, I'd think that if this is acceptable then the TB-3 should work like a charm if used in the same way.

 

Van Blerk

Van Blerk engines were the Rolls Royce of their day or pretty close. Huge displacement, low PRM and massive weight. I think there are only a handfull left in existance and mostly in museums so I don't think you will find one.

 

Ok working on my materials list I come up with a hull weight ( strip planked with diagonal veneers + an outer veneer aligned end to end. ) of 1,416lbs at 500sq/ft. Doesn't include the keel, finish, engine or internal framing like engine beds and bulkheads.

my goal is to keep it under 3,000lb dryweight, I'll likely go over by a little but its always nice to have a goal. The engines I'd picked are no longer available. I'm going with the belt drive thing I described but loose the flip up capability= no trany needed and neutral is a simple disengagement of the belt with a lever arm/tension pulley.

woods dirt cheap right now
500' ceder (5/8 x 7/8 with a cove in it )
250' cherry (3/16 veneer one inside one outside laid diagonally)
125' black walnut (3/16 veneer one outside finish)

ends up at 1 3/16 thick which is a bit heavy

$1,575

but thats before I add for waste so call it 2.5k and I'm grinning ear to ear. that and something like 25 gallons of glue. Still hoping for some feedback on the glue question guys.

in case your about to land-blast me for my wood selections consider this. All three are very rot resistive and all three have excellent glue properties, take finish well and are all available at the same mill, have very similar expansion and contraction characteristics and none react poorly to contact with certain metals.

Pondering what to make that keel and apron out of, cherry would maintain the same expansion and contraction rate so it might flex more evenly, but its not a very strong wood, based on what engine I find cherry might be plenty strong enough for displacement speeds. white oak is the more traditional wood and its a lot stronger, is about 7lb a cubic foot heavier though and there are rumors it doesn't take epoxy well. Any advice would be appreciated tho as nothing is set in stone till I actually have it loaded on the trailer.

 

Looking forward to your mistakes so I can avoid them, Bos

 

oh I'm sure there will be some. I'm kinda waiting on a few answers about glue and some opinions about my using cherry for a skin, that question about how close to place the molds in a strip planked hull and a few others but all in all once I get the materials sorted out and a few technicalities about the build process I'd say I"m pretty well ready to start slicing up some wood. Where are my people when I need em eh.

kinda cant wait to get cracking,

 

B.......I think you have heard this before but I'll repeat it for those that haven't.........

The structural design of any boat depends on the materials, construction method, framing method, operating speed, displacement, and the operational envelope (sea state)........A boat is not a house, every part is closely interrelated with every other part.....do you want to create a dogs breakfast or a great boat....your choice.....

The last house I built I cheaped out on some materials and methods.....I regretted that every day I lived in that house and promised myself I would never do that again.....The last custom boat I had built for my self I bought nothing but the very best available marine materials.....I have never regretted that (In fact I often congratulate myself on how smart I am ) especially 10 years on when doing maintenance......

One cannot advise on the skin construction method or materials without knowing the loads and the support system......

You have no design yet......thus it makes no sense to start cutting wood except in big chunks for re-saw later......

Start cutting finished sizes now and I guarantee there will be "If only I had...." somewhere down the road........