Brown/Marples Seaclipper 24MC

SC24MC Costs

John Marples said, the cost to build a SC24MC is between 5 and 10 thousand dollars, depending on materials used in the build. I don't know if John was including the cost of building the SC24MC trailer in his 5-10 thousaand dollar quote You also get the trailer plans when you order the plans for the SC24MC
A great, brand spanking new, little Tri well within the reach of most sailors and "want-to-be-sailors like me"...Don't you think...Even if it does cost a little more to build the trailer
I'm glad I kept those four 12" or 14" mag wheels and tyres...They'll come in handy after all

Cheers,

Bill

 

This design is probably the best I have seen in terms of ease of build, and ease of use... the boat is simple, practical, and probably the cheapest boat to build in the size range....

 

A Sc24mc

You get No argument from me mate But right now I've got to get my skates on and head-off for an apointment that I must keep.

Cheers,

Bill
Australia

SC24MC Sail/plan # 1.

 

Douglas Fir Or What?

G'day mates,

The plans for my SC24MC call for "Dry, Construction Grade Douglas Fir, Small Knots OK". Now, in the States and Canada, most times, buying good quality Douglas Fir is as easy as taking a trip to your local lumber yard and loading-up but...Not so here in Australia. The yards I've talked with don't know what I'm on about when I talk about Douglas Fir, so they try to sell me "treated" Pine or NZ Oregon!

I "think" a good "Untreated" pine "may" suite my needs but the NZ Oregon I've seen has to many knots...It's from young trees.

I'm seeking the advice from experienced Ozzie boat builders on this, what timber would you use in place of the Douglas Fir, for the Aka's (The two beams on a Tri) on my Tri? The measurements are for rough cut timber which I'll dress to size: 2 pieces x 8ft x 2in x 10in. 2 pieces x 6ft x 2in x 10in and 2 pieces x 8ft x 2in x 12in. 2 pieces x 6ft x 2in x 12in.

Thanking you in advance for your advice.

Bill

 

You can pretty much use any material you want for panels. Jim Brown once said to me that John Marples once said to him that you could make hull panels out of klennex, the loads were so small. I would use some kind of light weight brown ply like ocume, mersawa, whatever, but you can doubtless use pine. What maters is the black or purple exterior grade glue, and minimal voids, then sheath everything with glass and epoxy.

DF is a pretty uinique material, it is strong for it's weight, but more heavy than really necesarry, and quite easily split. Go to Forest Products Lab website, and get some numbers for Sitka spruce or black spruce, those are better woods than D-fir, and I can't imagine the Brown Marples team would turn up their noses at those woods. The reason I suggest starting there is that Black spruce, D-Fir and Southern yellow pine are the mojor stud grade woods in NA. That is what this is designed to use, I think (check that in your plans), so you can take the lowest numbers there for your comparisons, because there isn't another wood that actually compares to DFir on strength/weight, though there are better woods than DFir in timber, and any wood can be configured to match it. Then find some numbers on your local woods. Compare. Beam strength increases to the square of thickness and directly in proportion to width. So you can make minor adjustments without much difficulty. John Marples would doubtless give you some answers on this kind of thing since he is an actual engineer, and very supportive. He prefers phone calls, so maybe skype him.

A good way to proceed is to do your own testing. we used a bottle jack to break 18mmx18mm pieces of wood with the bottle jack resting on a bathroom scale, and the piece held fiirmly overhead in a rack. That way you can get actual measurements that are specific to the actual wood you are using, which is far more accurate than tables. But I can hear Jim saying "I just don't think you need to take it that far...". But the one thing is that once you have the info you have it for life and any other boats you may want to make, and you can update it as wood quality shifts.

 

G'day ThomD, Ply panels are not the problem, I can get marine ply at a good price, and I can get good CD exterior ply at a much better price I plan on using marine ply but...We'll see what I end-up with

The SC24MC plans call for DF for the Aka's. House frames here in Ozz are mostly constructed from construction grade Pine and/or Oregon, so I'll do some more checking before I decide what to use for the Aka's.

I agree with Jim on the timber testing To much of a hassle...I will most definitly "not" be building any other boats after this one, I have no wish to build another boat, nor would my health permit me to do so...This getting to be long-in-the-tooth is a pain in the ***...Specially when health problems come along for the ride but we have to live with things and get on with it.

Thanks for you views ThomD...I'll see what I can find out from Jim or John

 

Designer is always you best bet, but it would still help to know stats on your domestic woods.

Everyone shies away from testing, but all you need to do is place two brick on your bathroom scale, a suitable sized stick, and press down on it until it breaks, then compare. It is way more accurate as a basis than any amount of internet opinion, though admitedly getting the piece of dfir to compare migh be a hassle. A constant weight and deflection test is pretty easy also. Every single wooden arrow I shoot is tested, and that is just normal among archers, but when it comes to sending maned vessles out into the oceam it is all guesswork.

 

For what it's worth, what you antipodeans call "oregon pine" *is* what the right-side up part of the world calls douglas fir.

http://en.wikipedia.org/wiki/Oregon_pine

Probably called that because there's a fair amount found in Oregon. Or even in Colorado, (although a different subspecies) as it's what the heavy timber frame of my house is made; we needed to spec DF beams to meet the 120 lb/ft2 snow load requirement. Got a couple in my yard that crap all over the deck come pinecone season.

Most of the common construction lumber (as in studs) we see is DF as well, and pretty clear. I'd be happy to send you a few (they're only ~$3 for a 2x4x8 at Home Despot), but I think the shipping might be prohibitive ;-)

Mike

 

yes,
Living in Tasmania, I can also vouch that it is Oregon that you want. However, as you've discovered you wont get good quality in your local hardware store. Good specialist suppliers can get it, or as I've done, if you can get to where someone is demolishing an older home or building you can salvage very good oregon structural beams from buildings probably up until late 70s

 

Thanks mates

G'day Mike,

Antipodeans! I'm no bleeding antipodean! I'm a good old Ozzie
I'll have 8 of those DF planks you have at Home Depot but make them all 2"x12"x8', rough cut will be okay, I'll rip and dress them when I get them here

I have three 12'x2"x9.75", 100 year old plus, Oregon/DF planks in my shop, I found them in a wrecking yard and thought to myself, they'll come in handy down the track, so I bought them. (That was fifteen years back and they came from an old wool mill that had been demolished) Now I'll use them for the 2 pieces x 8' x 2" x 10" and 2 pieces x 6' x 2" x 10" (dressed down to 1.5"x9.5" as called for in the plans, for the aft Aka)
Now where will I find three more rough cut old Oregon/DF planks of 12'x2"x12" for the forward Aka I wonder...Would the admiral miss the big old DF planks in our roof space, they're beauts and would suit the job spot-on Better not, she might wonder why the roof's sagging

Thanks for your help Mike, I'll get there in the end or...I'll scrub the whole job, head off to the States and buy one of your old Timber motor yachts that no-one in the States seem to want but, again I'll have a problem...How would I get a 50' old timber built yacht back over the Pacific to Australia

Bill

G'day Captainsideburn,

Thanks for the info' mate, I can't find good Oregon in "any" lumber yard locally, it's all young NZ Oregon and that's no good for this job, just to many knots. I would be better of using good CG clear Pine.
I'll get round the wrecking yards again and perhaps I'll find the planks I need, that's how I found the 3x12'x2"x9.75" Oregon/DF planks I have in my shop

Thanks again for your advice mates,

Bill AU

 

Don't worry about the length

Western Red cedar is also good for use in this situation although it is not as strong as the Oregon. I wouldn't be concerned with the length or width. The timber will be stronger if you laminate it. Scarf it to make it to length and width. It will be better than a single piece that could split. Make it from Hoop Pine, Kauri, even clear radiata covered in epoxy is fine. I saw a radiata wing mast on a NZ 36ft Newick tri.

Where are you? If you are in Tassie you will be fine - King billy scraps. Qld you can find some Hoop Pine. Laminate it up and it will be great.

cheers

Phil

 

Folding/unfolding on water?

Now that there is some experience with the Seaclipper (in the 20') does it seem likely that the amas can be folded\unfolded singlehanded on the water?It would make the boat much more usable for me if it could do so due to narrow launch ramps locally. Many thanks, Dave

 

In another life I used to be one of Jim Browns agents.
When Jim started losing his sight John Marples came to his aid and became his exclusive agent.
Knowing Jims design philosophy as I do, I feel that the 24MC bears the fingerprint of John Marples more than that of Jim Brown.
It appears to be a successive development, in a series of scale, from his neat little 3mtr, single person trimaran.
I think it is a very attractive 24 footer, but there are a few things about it that I am not so keen on.

 

Such as? I feel the same way about the look of the cabin.

Dan

 

At least someone is making a lumberyard tri available. A roots return is never out of place and in the current economy makes a lot of sense. Not needing special molds or vacuum pumps makes for less initial investment and gives the backyard builder a tri alternative to the small Wharrams and Woods. The cabin does look basic but I imagine the more experienced builder could contemplate a different one.....