How much timber?

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sproggy
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How much timber?

Postby sproggy » Wed Feb 01, 2017 2:38 pm

I'm putting together an order for timber but I am confused by the bill of materials. I'm building the Nimrod but the same applies to all the boats I've looked at. For the frames, 35 bd ft is quoted. Then there are sizes given additionally for the sheers, chines, battens and keel.

What I don't understand is how 5 frames can possibly require 35 bd ft - an average of 7 square feet of timber per frame. Is that right? Or is the 35bd ft supposed to include enough for all the longitudinals too?

Mahogany is very expensive. I don't want to order more than I need but I don't want to run out either! Can anyone clarify how the BoM should be interpreted in this respect please? I fully expect to feel stupid once I hear the answer because I realise these things shouldn't require interpretation... :roll:

Thanks.

Ian

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Bill Edmundson
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Re: How much timber?

Postby Bill Edmundson » Wed Feb 01, 2017 2:47 pm

Ian

My advice for the frames is just get good material. By the time you finish this boat, any money saved on the frames will be nothing. The wood is not just the frames, it's the longitudinal, the deck framing, seat framing... some of it is saw dust and just drops(waste).

Bill
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Roberta
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Re: How much timber?

Postby Roberta » Wed Feb 01, 2017 3:20 pm

35 BF for the framing is not all that much. BF is 1" X 12" X 12". When you consider about 10-12 linear ft on average for a frame, 35 ft will go quickly. Some of the frame members will be curved resulting in more waste because the members will need wood that is wider. Then there are carlings, deck beams, seating and other things that pop up. The BoMs list mainly just the items needed for the basic hull. Decking, and other items will be extra. Plans will make basic suggestions on the finishing items, but because many builders like to personalize their boats, details are not always provided because of the many ways boats can be built.

Look over the patterns and size up the lengths and widths you will need for the framing. That way you can prevent having a lot of wasted cutoffs. All the other listed materials are in addition to the 35 BF. Like Bill suggested, Try to buy finished limber unless you are willing and able to resaw and finish plane the rough board foot timber. About 30% of your wood will be sawdust and firewood.

Roberta
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sproggy
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Re: How much timber?

Postby sproggy » Wed Feb 01, 2017 11:04 pm

Thanks Bill and Roberta for your replies. I am dividing my timber purchasing into phases - phase 1 is for the hull structure, phase 2 is planking/outer longitudinals then phase 3 is decking and fit-out. This approach is partly for budget reasons, partly to avoid me having to store too much material in a limited build space. Quality timber is quite expensive here (35bd ft of mahogany will cost around £400, an 8x4 sheet of 3/4" marine ply £160) and while I do definitely want that quality I don't want to buy more of if than I need.

The mahogany I buy will be planed (25mm rough down to approximately 19mm finished) by the supplier which is an extra expense but a job I wouldn't want to do myself. It'll make working much easier. I'm trying to be clever when ordering for the longitudinals to minimise wastage - the supplier sells in a variety of widths and thicknesses so this should be easy enough. Most of the wastage, as you say Roberta, will be from cutting the frame members which are irregular shapes.

Thanks again!

Ian

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Re: How much timber?

Postby JimmY » Thu Feb 02, 2017 1:40 am

Hi Ian,

For another data point, I'm building a Squirt (11' boat), and I bought 28 bd-ft of 4/4 Sapele and used almost all of this for the frames, battens, and keel. There is a lot of waste and how much depends on the widths of the boards you get. I needed another 20bf-ft for the sheers and chines. Also allow for screwing up a piece or two as you get started. I do have a few pieces left over, and these will be used on the sub-deck structure.

You might consider Sapele over Mahogany. It has a beautiful grain and color, machines well, and is about half the cost of Genuine Mahogany (at least here in the States).

So, 35bd-ft for the frames sounds a little tight for a 15' boat from my point of view.
-Jim
Nothing says poor craftsmanship like wrinkles in your duct tape!

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sproggy
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Re: How much timber?

Postby sproggy » Thu Feb 02, 2017 2:01 am

JimmY wrote:You might consider Sapele over Mahogany. It has a beautiful grain and color, machines well, and is about half the cost of Genuine Mahogany (at least here in the States).


The supplier I'm planning to use doesn't list standard prices for Sapele (although they do mention it on their website) so perhaps it's less easily available over here. Or maybe just not so popular. But thanks for the tip - I'll ask them about it. They say it's less durable than mahogany but then the boat won't live in the water and it'll be encapsulated.

Total timber cost (mahogany, ply, cheap construction softwood for the build form) including tax but not including planing comes to £1,620 (just over $2,000) - that's for a completed hull up to the 'flip' stage so no decking or interior. Then there's £400 worth of silicon bronze fasteners and close to £300 worth of epoxy. This is not a cheap project, but then I never really expected it would be. I thought the motor would be the single biggest expenditure but it seems the timber wins that little competition. You'll probably think that sounds very expensive (so do I!) but I believe it simply reflects the market rates in our country.

I'll stick with the 35bd ft recommendation from Glen-L for the moment. You're right - I may well screw up. And it may be tight. But I can always order more if I need to. This project won't go quickly due to work and family commitments so that much will keep me going for a fair while.

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hoodman
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Re: How much timber?

Postby hoodman » Thu Feb 02, 2017 4:32 am

$2000 for all the timber and plywood for the hull is not too bad. Although it is probably more than I spent for a larger boat that used thicker ply, it is not shockingly so.

I would second checking the price for sapele. Lots of folks over here are using it with great results. At my local supplier it has price parity with white oak. Just make sure you're getting quarter sawn.

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sproggy
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Re: How much timber?

Postby sproggy » Thu Feb 02, 2017 5:15 am

White oak here (well, at the supplier I'm looking at) is 82% of the cost of mahogany. So maybe less of a difference than in the US but oak and sapele could be further apart in pricing here than they are there. If sapele is similar in price to oak I'll stick with mahogany as the difference isn't significant.

Iroko is very slightly cheaper than mahogany but I recall it's not nice to work with, plus I'm not keen on its colour.

My list of questions for the timber supplier is getting longer..... Sometime soon I'm going to have to just make a decision, place the order and then get on with it. I'll be calling them tomorrow.

Mark-NJ
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Re: How much timber?

Postby Mark-NJ » Thu Feb 02, 2017 5:16 am

Bill Edmundson wrote: The wood is not just the frames, it's the longitudinal, the deck framing, seat framing... some of it is saw dust and just drops(waste). Bill


What Bill said is spot on. I would only offer this: Even very small, irregular-shaped pieces that look like 'drops' when you cut them have a way of finding their way into your build later on down the line. Don't pitch / burn any of them....throw them all in a box. You'll be surprised how many 'little pieces of scrap" wind up getting used. A support stop here, a brace block there, etc.

Hold off on the bonfire until the very end....

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Roberta
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Re: How much timber?

Postby Roberta » Thu Feb 02, 2017 5:42 am

Definitely hold off on the fire till the end. Small pieces will be used for things like blocking.

Roberta :D
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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sproggy
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Re: How much timber?

Postby sproggy » Thu Feb 02, 2017 6:57 am

If it all goes horribly wrong I'll be having a much bigger bonfire than just the offcuts.... :lol:

Point taken, though - don't throw anything away.

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hoodman
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Re: How much timber?

Postby hoodman » Thu Feb 02, 2017 8:04 am

In the end I'm figuring I'll have plenty of small oak pieces to make a nice end grain cutting board.

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sproggy
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Re: How much timber?

Postby sproggy » Thu Feb 09, 2017 8:09 am

I've been onto two suppliers (well, three, but one of them was trade only so wouldn't deal with me) and both have recommended utile. Sapele is around 20% cheaper than utile (so the same price as white oak, as noted by hoodman) but the guy I talked to at some length reckoned the difference in quality was greater than the difference in price. 'Proper' mahogany is 2-3 times the price of utile and is less regular in both colour and grain. Too rich for me anyway.

So I'm going for utile. Of the two suppliers, only one (Robbins - http://www.robbins.co.uk/marine/index.asp) could guarantee me all quarter sawn boards so I'll go with them. Other deciding factors were that Robbins also offer what's reckoned to be some of the best marine ply in the country and quoted a slightly better price all-in.

So now I know what I'm getting I just need to prepare the garage.....and warm up the credit card....before placing the order.

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Roberta
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Re: How much timber?

Postby Roberta » Thu Feb 09, 2017 8:37 am

Great!! Keep us posted.

Roberta :D
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

Hercdrvr
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Re: How much timber?

Postby Hercdrvr » Thu Feb 09, 2017 2:08 pm

I prefer to do the grocery shopping and get $40 cash back then use it to buy another piece of lumber. Gotta keep my costs under the the promised $1500 total boat cost. I think she's on to me though.

Best use for scrap plywood is to use it to make templates for your next boat build.

Matt B


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