Oak Timbers

[jimschofield]

Hi builders,

I'm putting a cutting list for the oak timbers. Does this look right ?


2 posts, 1320 x 60 x 50.     

6 header pieces of 830 x 60 x 25.    

5 keel pieces, 1200 x 60 x 60.


Does the oak mast support bridge attach to frame D1 on the jig or are they put in afterwards ? From what I can see, Trekka blog does not show them before planking.

Also, has anyone considered putting the keel timbers on the jig, as per the B&B video. The bunk sides give the correct shape but are tabbed into the frames, so would those tabs have to be cut to release them after turning the hull, to put in the keel timbers ?


I'm building the 580 in my head first !!!


Jim

[peterbrumby]

Sept 10, 2020 8:46:46 GMT jimschofield said:

Hi builders,

I'm putting a cutting list for the oak timbers. Does this look right ?


2 posts, 1320 x 60 x 50.     

6 header pieces of 830 x 60 x 25.    

5 keel pieces, 1200 x 60 x 60.


Does the oak mast support bridge attach to frame D1 on the jig or are they put in afterwards ? From what I can see, Trekka blog does not show them before planking.

Also, has anyone considered putting the keel timbers on the jig, as per the B&B video. The bunk sides give the correct shape but are tabbed into the frames, so would those tabs have to be cut to release them after turning the hull, to put in the keel timbers ?


I'm building the 580 in my head first !!!


Jim

[peterbrumby]

Sorry Jim...didn’t do the reply right.

My numbers are slightly different, but I took them before the corrected sheet that was issued the other day.

I assume also the keel pieces (5) you intend to cut down as I believe they are all slightly different lengths.

I can send my numbers when I get back to my machine if it helps.

Peter

[jimschofield]

Thanks Peter,

I'm measuring for the longest keel piece and then cut them all down.

I'm wondering could we use three header pieces of 60 x 50mm each, so three instead of six. Or are we required to have all the six pieces laminated together for extra strength ?

Jim

[peterbrumby]

Hi.

To be honest I just took as off the plan and will laminate all 6. Total came to £260 from a local oak supplier.

i plan to install after I have flipped the hull.

i thought about putting in on the jig but decided too complicated, especially if I didn’t get it right! 

I also previously thought the the whole of the bunkside was to be “watertightish”, including the piece that was under the cooker and chart table. However I see on Trekka these have been cut away, which is useful.

Peter

[pete]

Hi Jim,
I am trying to follow fairly closely the B&B video construction method - i.e. using bunk sides/ cockpit sides on the jig to locate frames, and adding the oak floors at this stage, so not having to then remove the bunk sides later to fit the oak floors once the hull is turned.
I used the templates on one of the B&B drawing sheets (Fyne will have these if you don't have them already) to cut the floors to the right profiles. They appear to line up well, but i've not let those stringers in fully yet, so can't say for sure. I'll pop a couple of photos on my blog to show the general arrangement as it stands.
I did a post about making frame D1 - I've used solid oak for the floors, but laminated would also be good - and maybe less prone to shakes, twisting etc as it dries out (assuming its not stable already), and thinner planks are substantially cheaper.

For the uprights and cross piece - the B&B video seems to indicate oak, but once i weighed a bit of it, the cross piece especially is far too heavy at that height in the boat in my opinion. Also massively over engineered. The plans do not call out oak for this piece. I laminated up some nice dense bits of douglas fir and used these for the uprights and the cross piece. Also - note the cross piece could really do with tying into the half deck beams in frame D1 - which they don't if you follow the plans. The blog post has a little about this bit too, for the sake of a tiny amount more material the strucutre gets a lot stronger.

I overbought on the oak somewhat (even when you include the bowsprit)... if you're interested in a 65mm thick rough sawn plank of fine, knot and shake-free material let me know! Not sure what the postage is like on a 20 kilo 2.5metre length will be though...

[jimschofield]

Thanks guys,

Different ways of doing the same thing but I've a much better idea of what I'm doing now. Great series of pictures Pete, and I envy your workshop and joinery skills !

Thank you for your offer of the oak but I'll get some sizes together and call in to my local joinery, might be cheaper than shipping.

I've begun cutting out the jigsaw pieces from the pile of plywood and my frames await building, I'm way behind you both, but the Winter is long.

Jim

[pete]

No worries Jim, enjoy the build! The kit seems to be going together very nicely so far. I'm just doing random evenings on the boat, can't commit to full days at the moment, so depending on the workshop time you can get you may well catch me up pretty quickly!

Just noticed your original post - might be worth a double check of the cross section of the oak floors, I think they are 60 x 70 mm, not 60 x 60. I'm not at the shed just now, so cannot measure what i've made, but the old template I found in the bin seems to be 70mm deep. You may want to measure the notches in the bunk side piece before ordering.

[peterbrumby]

Sept 11, 2020 12:53:20 GMT pete said:

Hi Jim,
I am trying to follow fairly closely the B&B video construction method - i.e. using bunk sides/ cockpit sides on the jig to locate frames, and adding the oak floors at this stage, so not having to then remove the bunk sides later to fit the oak floors once the hull is turned.
I used the templates on one of the B&B drawing sheets (Fyne will have these if you don't have them already) to cut the floors to the right profiles. They appear to line up well, but i've not let those stringers in fully yet, so can't say for sure. I'll pop a couple of photos on my blog to show the general arrangement as it stands.
I did a post about making frame D1 - I've used solid oak for the floors, but laminated would also be good - and maybe less prone to shakes, twisting etc as it dries out (assuming its not stable already), and thinner planks are substantially cheaper.

For the uprights and cross piece - the B&B video seems to indicate oak, but once i weighed a bit of it, the cross piece especially is far too heavy at that height in the boat in my opinion. Also massively over engineered. The plans do not call out oak for this piece. I laminated up some nice dense bits of douglas fir and used these for the uprights and the cross piece. Also - note the cross piece could really do with tying into the half deck beams in frame D1 - which they don't if you follow the plans. The blog post has a little about this bit too, for the sake of a tiny amount more material the strucutre gets a lot stronger.

I overbought on the oak somewhat (even when you include the bowsprit)... if you're interested in a 65mm thick rough sawn plank of fine, knot and shake-free material let me know! Not sure what the postage is like on a 20 kilo 2.5metre length will be though...

Jim

your boat is looking very tidy from you blog pics. Looking great. I reckon I gotta spend a couple of days tidying so I can get some pics up lol!

interesting you had a couple of similar experiences to me too. Reassuring actually.

Peter

[jimschofield]

Pete,

You're right about the size. I measured the slots on the bunk side and they have slots 70 x 60 for keel timbers, one big one for the double on D1 and one smaller one.

And Peter,

When I get a chance, I'll check out that "watertightness" on the bunk floor area of Trekka. I though that was the whole idea ?

Jim

[Admin]

Sept 11, 2020 20:34:58 GMT jimschofield said:

Pete,

You're right about the size. I measured the slots on the bunk side and they have slots 70 x 60 for keel timbers, one big one for the double on D1 and one smaller one.

And Peter,

When I get a chance, I'll check out that "watertightness" on the bunk floor area of Trekka. I though that was the whole idea ?

Jim

Interesting conversation..thanks...YES just the BUNK RISERS need to be watertight so if you have water in the central sole area it will not flow into and under bunks creating destabilising free surface effect...so any water in the bunks stay there and in the center section stays there....On Trekka II I am making the aft sections lockers of both bunks completely watertight...the other two normal lids...but I will put bung drains in all locker compartments to empty if they have water in them after any flooding incident. Under galley and chart area are NOT watertight and my locker fronts will hinge up to hold heavy water in them....good luck