Hull choices

[JohnsonM50]

A potentially good subject was started and went by the wayside, Id like to start it over. [to learn or inform]
Wood as a choice for kneeldowns has been It for many years, polyester & glass is too heavy as in strength to weight.
Composite boats have strength and lightness thats hard to beat however in weight limited classes is it better to put weight where you want it [lead] or run a rig close to required weight and have the drivers mobility factor play in? Would that be an advantage to a heavier driver?
In unrestricted weight racing composite is probably best. How is it in terms of service life and fatigue ?
Wood is something Ive learned a little about over the years. I see at the local races that by far most kneelers are wood and most of them are Sitka Spruce framed [exellent wood] and Okoume/Gaboon plywood skinned. Okoume has a good strength to weight ratio, its drawback is that its natural duability is low [it will rot rapidly]. It is reccomended that the construction method be epoxy saturation-all surfaces, all edges. Many of these boats use weight to make them legal, that brings me to think of another choice. Sapele/Sipo Its a little heavier and a little stronger and has twice the durability. Okoume = non durable, Sapele = moderatly durable.
Harbor Quality Products lists a rating scale.. very durable - 25+years, durable -15yrs, moderatly durable -10yrs, non durable -5yrs and perishable-less than 5. [The only listed wood at very durable is Teak] Sitka Spruce rates well as light, strong and moderatly durable as well as Honduran Mahogany is shown to be a little heavier than Sitka, not as strong [but close] it is however rated as durable making it a good transome choice.
With so many variables to consider the similarities we see in the boats today must be for good reasons. I have an interest in building good quality boats in the future and welcome thoughts, experienced or new.

[Charles Salsman]

If you want a heavy wood that is impervious to water, there is none better than Black Locust. There is a thread at BoatDesign.net about this.

[JohnsonM50]

If you want a heavy wood that is impervious to water, there is none better than Black Locust. There is a thread at BoatDesign.net about this. Very interesting.. I took a few miniutes to look, I will have to go back later to find it. I know locust is very strong and in a young forrest will grow pretty straight & knot free to compete for sunlight. Its being good for marine use I hadnt heard, Thanks

[Charles Salsman]

It's not really a good marine choice because of the heavy weight. But if you're wanting to add weight and build with wood, then it's for you. And it's cheap and not commercially extinct like mahogany (genuine) is, or teak will be.

I dont know if it varies from region to region, but the locust that grows in the mtns of western nc is the type that I can personally vouch for.

Good luck

[Skoontz]

As a landscape contractor, I'll tell you that Black Locust thrives in wet spaces where very else will grow. That tells me it's wood, other than the weight would be a great choice.

[RichardKCMo]

Locust is the way high on the chart of density, higher than oak, on the list of firewood ,splits easy now that my splitter's working push ,pull handle, its like third behind some , nearly 30 mill. btus. It's all good.
RichardKCMo [ QUOTE=Skoontz;29316]As a landscape contractor, I'll tell you that Black Locust thrives in wet spaces where very else will grow. That tells me it's wood, other than the weight would be a great choice.[/QUOTE]

[JohnsonM50]

It's not really a good marine choice because of the heavy weight. But if you're wanting to add weight and build with wood, then it's for you. And it's cheap and not commercially extinct like mahogany (genuine) is, or teak will be.

I dont know if it varies from region to region, but the locust that grows in the mtns of western nc is the type that I can personally vouch for.

Good luck For kneeldown / laydown type boats it wont be a choice but if you were building a sailer where ballast is needed it could be used in framing.

[JohnsonM50]

I dont mean to say race boats need to be heavier at all, where lead is used to make weight is where it might make sense to be a little heavier hence stronger.

[Charles Salsman]

Ok, but consider this. You're impregnating those other woods with epoxy. I wonder what the weight comparison would be to the locust Im referring to, untreated. And would you need the same dimensional lumber. (Not sure how it compares strengthwise)

Those guys at boatdesign.net are always playing around with different ideas like that, theyve probably got 20 threads going about materials at any given time.

[David Mason]

But I don't think most of us are impregnating the wood with the epoxy. We are simply sealing it of with a thin coat. The decks perhaps a thicker coat as it needs to be painted or clear coated for UV protection.

I also think there are a hundred different ways to come to the same results on building boats. I think it comes down to personal preference more than anything. I prefer the softer woods for stringers and frames because it mills a lot easier and saves me from buying a lot of blades. They certainly hold up well for our application. I have a 14 year old Roper hydro that was used heavily for about 12 years. When I say heavily, it raced all season, every season as much as I could in the mod FEH class. The boat is still in great shape, and I finally had to paint it from its natural finish after the 12 years. Just to many battle wounds for it to be pretty natural any longer. I believe sitka spruce was used in this boat. The only reason it is not racing actively today is it gained weight with all the minor repairs over the years from those dumb azz moments. It did whip the drawyers off the Nat Champ in FEH at the Contantine race a couple years ago with the fresh paint. My dad drove it as he is light, and the boat handeled great. I think he would have ran it out of gas running around if we had let him.

[JohnsonM50]

Ok, but consider this. You're impregnating those other woods with epoxy. I wonder what the weight comparison would be to the locust Im referring to, untreated. And would you need the same dimensional lumber. (Not sure how it compares strengthwise)

Those guys at boatdesign.net are always playing around with different ideas like that, theyve probably got 20 threads going about materials at any given time.
Thats a fair consideration but like Dave wrote the epoxy when used is thin [would run off if it werent] and you need to coat the other wood in something. My airborn is white oak, honduran mahogany and sitka spruce- [has been used in arrows and aircraft for some time]. It seems to be predominant in kneelers.