Bowsprit spruce or douglas fir

[BlackPig]

I need to make a bowsprit for my heard 23. 4 inches diameter and overall length of 15 feet 9 inches with 11 feet projecting forward of the stemhead.

What would be best spruce or douglas fir.

Thanks

 

[Billy_Mizzen]

From my perspective it’s a toss-up between strength/stiffness and weight, bearing in mind that one thing no boat appreciates is weight in her ends. Also bowsprit length will play a big part in the specie selection, as a longer bowsprit will have a greater moment acting on it, and if supported by a bobstay, will also be subject to buckling from compressive loads.

Douglas fir is approximately 24% stronger in bending than spruce and also around 26% stiffer but the penalty is a 15% gain in density over spruce.

The load the bowsprit is subjected to can vary from very little when in static condition to having to react the dynamic loads produced by sailing upwind. The bowsprit could be considered to be subject to bending in at least two planes, firstly reacting the sideways and aft pull produced by the Jib and secondly reacting the main sail leech via the forestay. Also pitching will add another dynamic factor to the argument, relating required strength/stiffness to displacement and righting moment.

For what you intend and to gain the strength/stiffness required I would have thought Douglass Fir probably seems the best bet. However this would also be highly dependent on using a sufficient diameter section.

 

[Peterduck]

If 'twere mine, I'd be going with ash, and hang the couple of pounds extra weight. You're not racing at the top level are you? Much better to have a really strong bowsprit which won't let you down when the going gets rough. Don't forget that no bowsprit doesn't just mean no jib, it also means no real tension on the mainsheet too. When I sold my old ketch, the new owner took it into a local boatyard which specialises is wooden boats. The yard owner replaced the oregon bowsprit with one from Merbau, a tropical timber as hard as iron, and just as strong. The boat was going to Tasmania, which meant crossing Bass Strait, where the Roaring Forties funnel into a narrow gap between the mainland and Tassie, and you need everything to be sound.
Peter.
Peter.

 

[pyrojames]

I'd be heading fro douglas fir. My mast and boom are both Douglas fir. For small trade of in weight you gain a very strong flexible timber, less prone to rot than spruce.

 

[BlackPig]

thanks for the tips. I will probably go for the douglas fir.
Graham

 

[Rum_Pirate]

What is wrong with using sitka spruce?

 

[Tranona]

What is wrong with using sitka spruce?

Simple. It is over twice the price of Douglas Fir, less strong and even if it were strong enough in the section needed the weight saving is not justified for this application.

 

[oldfrank]

Ash will rot - quite quickly. Sitka is fine but dents easily everytime something hard touches it - Douglas is heavy but will probably last the course (ish). You also could of course try larch.

One of the hidden aspects of selecting grown poles is the current tendency to grow trees too quickly. The more growth rings you can get in your required diameter the better. Slow grown timber from the tree-line is favourite. You can, for example still buy pitch pine for spars but it's grown too quickly to last. To give you a couple of examples - Excelsior's first mast was Douglas (It was a seriously large piece of wood). This first mast lasted a mere five years before the top fell off. The replacement was larch from a Scots estate and grown on the tree line. Someone counted 143 growth rings in the log; and the mast must have been in use for nearly twenty years without a problem. This information may not be entirely germane to for a spar as small as a bowsprit but how quickly the wood is grown is paramount. Favourite is a Scotsman with a plantation near the tree line. Rainwater (and the ability to keep it out) is probably more important than the species of tree. If you're not in a hurry, don't overlook the option leaving it to soak in salt water for a while. Saves finding anywhere to store the damn thing. OF

 

[Transcur]

Douglas fir, Columbian pine will be far better. If you have a traveller on the bowsprit it will dig in far moreeasily in to the soft spruce.

 

[BlackPig]

I was thinking of putting a dingy keel band on the lower side to stop wear from a traveller.

 

[Woodlouse]

We have two bronze strips underneath our bowsprit. But thats more for protecting it when running it inboard. The traveller is leathered to stop it wrecking the varnish and wood.

 

[mikeinkwazi]

Oil or varnish?

We have two bronze strips underneath our bowsprit. But thats more for protecting it when running it inboard. The traveller is leathered to stop it wrecking the varnish and wood.

My vote is Douglas Fir. I made a 10ft laminated bowsprit last winter and it has proved well up to the job. BUT, I used boiled linseed on it and am now sanding and scraping off the black! Any suggestions for next season? (oil/varnish/what?)

 

[BlackPig]

Why laminate, and not a solid pole?

Thanks for all the replies this thread by the way. Merry ychistmas

 

[Seagreen]

My vote is Douglas Fir. I made a 10ft laminated bowsprit last winter and it has proved well up to the job. BUT, I used boiled linseed on it and am now sanding and scraping off the black! Any suggestions for next season? (oil/varnish/what?)

International Original. Since my sprit is 18' of columbian pine, which bends like a CB aerial when beating I need something easy to apply, retouch, and bends.

 

[jon]

Why laminate, and not a solid pole?

Very good point, I wonder what went wrong here:
http://www.hebridesnews.co.uk/clansman_aids_stricken_yacht.html
The Morwenna also broke her bowsprit, earlier this year,on her sail down to Padstow from Bristol.
I think, but am probably wrong, that the spars were made by Nobles from douglas fir and hollow. Problem with hollow sections is that they can only bend so far before failing and rely on the glue joints being 100%.
Use resorcinols glues and spruce for a solid bowsprit would be my recomendation.

 

[BlackPig]

Happy new year all.

I got my wood 100mm X 150mm 4.9Meters long of Douglas fir £82. So I will start work on the bowsprit next week. I will cut off the 50mm and us it for the toe rail. Yes I know I should use a hard wood. But this is spare wood and allows me a practice run and very little cost.

I have still to decide on the fitting hinged or keep the old system.

Graham

 

[xtiffer]

My vote is Douglas Fir. I made a 10ft laminated bowsprit last winter and it has proved well up to the job. BUT, I used boiled linseed on it and am now sanding and scraping off the black! Any suggestions for next season? (oil/varnish/what?)

4 coats of clear epoxy primer such as Wood Impreg 120 followed by
5 coats (min) of 2 part poyurethane varnish such as Seatop PU 360UV.
Cheers,
Chris

 

[oldfrank]

Ooo. Careful! Two part poly on real tree wood doesn't let the water out and it's also a complete b*st*rd to strip back to bare wood to refinish. Single pack is OK - personally I'm so convinced that Epifanes is the best varnish in the world that I haven't botherd to try anything else for years. Don't forget to heat it up to get a good winter finish. It does somewhat depend on dimensions but epoxy might not like an extremely flexible bowsprit and crack ... and then the rainwater gets in. That's nothing more than my personal opinion.

I always remember an Essex wildfowler who thought he'd build himself a really light punt. The end product was epoxy sheathed and glued. Unfortunately the epoxy just shattered on the recoil from the punt gun and he got his feet wet. Pity really!

 

[xtiffer]

I agree that Epifanes is absolutely the best one pot varnish around.
For many years I also would use nothing else.
However, the new epoxy primers are a revelation; easy to apply and they have a degree of flexibility that deals with expansion/contraction and glue joints.
Try them and you may well change your mind.
The peace of mind gained from having no chance of water ingress under the
coating is fantastic.
Only downside for me is that it will cut down my employment possibilities
Cheers,
Chris

 

[BlackPig]

Bowsprit now in full production. While planning it I wondered which way should the grain be? I guess it would be stronger running vertical, but maybe easer for water to ingress. Horizontal not as strong but less like for water penetration. Is there a recommended way.