Rascal Runabout started - more wood questions

[DavidS]

Hi,

I've started the Rascal runabout and have finished all of the frames and transom. The frames were built from a good quality spruce (nearly clear) but my supplier (Randall Brothers in Atlanta) is no longer carrying this wood.

I am starting to look at alternatives for the chine, shear clamp, and planking battens and for these I need 16 ft. lengths. Some folks have suggested Douglas fir but others say that it will break and will be difficult to work with (and may require steam bending). Another possibility is spanish cedar (similar to mahogany). Some other possibilities would be cypress or yellow pine but I don't know much about these types of wood and I hesitate to use them.

Any ideas?

Thanks in advance,
DavidS

[JimD]

Doug fir ought to do just fine. Choose the lengths carefully for straight grain. True, you can only coax so much of a bend out of it, even with steaming, and it will snap on you if you ask too much of it, but lots of boats including a couple of mine use df for the parts you mention. Sometimes just soaking it with water for several days is enough to make it suitably flexible. Resawing the ends at tight bends such as the bow can be helpful, and taking the time to laminated two or three thinner strips with epoxy gives excellent results.

[ 12-30-2005, 04:56 PM: Message edited by: JimD ]

[almeyer]

I used doug fir for the stringers and keelson on my 14' daysailer, and it worked fine. The stringers took not only a healthy bend but also a severe twist near the bow. No steaming. I couldn't find any clear straight grained wood in 16', so I scarfed together 10 and 8 foot pieces. Worked well.
Al

[Graham Knight]

I used DF on my Glen-L Squirt, it'll go round just fine, especially if you do as Jim says and laminate thinner strips.
That also gives you the opportunity to use up some shorter lengths by scarfing them together, stagger the scarfs in the laminations and it'll be just as strong as solid.

[ion barnes]

In the interest of lightness, I would make enqiries with a local Experimental Aircraft Assc. chapter for a source of spruce. Their supplier maybe over the top quality-wise but... Otherwise I would be looking for cypress or as we call it, yellow cedar.

[Bob Smalser]

Since DF is relatively cheap, I'd consider redoing the frames in it, too.

No reason to use rot-prone spruce for anything in a boat with access to DF.

Reduce the scantling specified for spruce by 15% and use the stronger DF, and you have an assembly just about as light and every bit as strong.

http://pic3.picturetrail.com/VOL12/1104763/2595357/29566094.jpg

I bent those 1 7/8 X 2 DF chines framing the bow curve of this punt....but had to kerf them, first.

[ 12-31-2005, 08:56 PM: Message edited by: Bob Smalser ]

[Speedboy]

Dave, when I started building Rascal I wrote Ken Bassett, the designer, because I could not locate a source of spruce for the sheers, chines, and battens. He wrote back saying mahogany was acceptable for all three. He also said you could use spanish cedar for the battens and vertical grain douglas fir for the chines. I ended up used mahogany for everything. Where the battens, chine and sheer approach the ash stem from station 1, I found the only way to get the wood to take the severe twist was to steam them. I cracked one of my 16' long mahogany sheers before I realized steaming was one way to make the twist between station 1 and the stem. I did use spanish cedar to replace the cracked sheer. It felt lighter than the mahogany, and I hear that the sawdust is bad for you (wear a mask), but it worked out fine.
For the battens, since there were so many, I had the local lumberyard set up their moulding machine and it spit out a whole pile of the battens in no time. I think they charged me $60 for a milling charge, but the battens were dimensionally identical with a real nice finish. You may want to consider doing this to save time. Congratulations on your progress and good luck with the build.

Speedboy

[imported_chris]

I also used mahogany for all. Its a little heavier, and harder to bend. But there is very little to bend that severely.

[shellback]

I built RASCAL several years ago and for the chines I used Doug fir. It's hard to find lengths of clear material but if you visit a good lumber yard (or flooring supplier) you'l find T&G flooring in lengths to 19 and 20 foot! Select good stock, rip the T&G off, and then laminate them.

[ion barnes]

How about yellow cedar (cypress)?

[ion barnes]

bump

[Bob Smalser]

Originally posted by ion barnes:
How about yellow cedar (cypress)?AYC is about perfect, and you can get it in BC at a reasonable price...almost as heavy and strong as DF but more rot resistant, easier to bend, and easier to work.

But I don't think it's either easily or inexpensively available for David in Atlanta.

And much as I love H. mahogany, it's mostly milled for cabinetmakers, not boatbuilders, and I've rarely encountered locally-available stock without sufficient grain runout to make it an expensive proposition for bending, given the waste.

[ 01-07-2006, 03:21 PM: Message edited by: Bob Smalser ]

[Bill Perkins]

David I'm sorry to hear that RB have dropped the clear Spruce .I made my chines from their clear Douglas Fir , which is down at the Narjoe yard .The stuff is stiff all right ,but I laminated mine in place useing 2 lams . With the perfect bending form already built ,glulam seemed like the easiest solution with that material .

I just barely made my bend .If it was no go I was prepared to resaw the forward ends on the bandsaw,switching from 2 lams to 4 at the tight forward bend .The strength to weight ratio of the fir is not bad ,and it's more durable than the Spruce . There is a nearby supplier of Aircraft grade Spruce , but I've not even priced that stuff .

[DavidS]

Thanks to everyone for replying.

I called Ken Bassett, the designer of the Rascal, a few days ago and we chatted for quite a while about different types of wood (I gathered that things were slow over the holidays and he spent some extra time talking to me). Ken mentioned that he had used Douglas fir in the past for chines but he had to slice some of the boards with a bandsaw to get them to bend sufficiently. This would be similar to laminating them as others have mentioned here but only the ends that needed more flexibility would be cut. Ken also mentioned that it would be possible to use mahogany but this is getting pretty pricey, at least around here.

On one of my trips to a local lumber dealer they showed my some Spanish cedar and suggested that it looks almost like mahogany but at about 1/2 to 1/3 of the price. I asked Ken about using Spanish cedar and he said that it should work fine for the chines, shear, and planking battens. He also mentioned that a guy in Alabama has decided to use Spanish cedar to build the entire boat (including the topside and deck planks). I would really like to see that boat when it is done.

I also asked Ken about cypress and he said it would probably work just fine but being up North he wasn't too familiar with it and so couldn't offer any first-hand opinion. From what I have read on the web, there may be problems in using epoxy on cypress but I don't know for sure.

Bill P. - thanks for info, I have built the frames for Rascal using the white spruce from Randall Brothers. They are nice folks and have been helpful, it's too bad they will not be carrying this any more. I visited the Narjoe lumber yard a few days ago and looked at some of the fir. I've been visiting alot of lumber yards lately.....

At this point, I'm planning to use the Spanish cedar to the chines, etc. It is about the same price as the Douglas fir and I like the way it looks.

Thanks again to everyone.

[Graham Knight]

Spanish Cedar was used by Chris-Craft after the war when Mahogany was hard to get, they painted it because it didn't varnish as nicely.
There's a large boatyard locally specialising in wooden boat repair, and they use it extensively because of the price of Mahogany, samples I've seen have been quite heavy, I don't know how well it bends but apparently rot resistance is very good.