|
|
30-06-2017, 17:03
|
#16
|
Registered User
Join Date: Feb 2017
Location: UK
Boat: Jeanneau 371
Posts: 192
|
Re: Wood, aluminum, or steel for new bowsprit.
Quote:
Originally Posted by F51
Yet again time to play catch-up on the sprit. The original bowsprit was milled from one 9"x9" x 13-foot piece of mahogany. I'm tired of trying to keep the rot at bay, so I am looking to replace the whole thing with teak, aluminum or steel. Even here in teak country a 13-ft chunk of a tree is not going to be cheap. First quote for the teak was $3100. Ouch! Now I know why the builder used mahogany! I can get aluminum or steel square tube for a lot less. I am leaning toward the steel since any competent welding shop can cut and reseal the front part so it looks like a sprit. Then weld on some pad eyes to accept the stays.
Do I seal it up airtight or take it to Guatemala city to be galvanized inside and out? I'm sure I could find some good hard paint to adhere to the galvanizing.
Who on the forum has had experience building a bowsprit out of metal? Any special problems or concerns?
Thanks for any help. The combined wisdom here is awesome!
|
I built a bowsprit out of 2" stainless tube for my endurance 37' Designed by Peter Ibold. No problems I'm sure the design is available.
|
|
|
30-06-2017, 17:53
|
#17
|
Registered User
Join Date: Mar 2011
Location: fl- various marinas
Boat: morgan O/I 33' sloop
Posts: 1,447
|
Re: Wood, aluminum, or steel for new bowsprit.
Strange dimension, 13'. Does it need to be so long to reach a cross brace? Steel or aluminum easiest, AL no corrosion issue. Why rectangular tube? a slightly thicker channel might be easier. No welding, just use bond breaker for bolted fittings.
|
|
|
30-06-2017, 18:05
|
#18
|
Registered User
Join Date: Apr 2007
Location: Marina del Rey, California
Boat: President 43 Sportfish
Posts: 4,105
|
Re: Wood, aluminum, or steel for new bowsprit.
Quote:
Originally Posted by Dave22q
...Why rectangular tube? a slightly thicker channel might be easier...
|
Channel is no good for a bowsprit.
__________________
1st rule of yachting: When a collision is unavoidable, aim for something cheap.
"whatever spare parts you bring, you'll never need"--goboatingnow
"Id rather drown than have computers take over my life."--d design
|
|
|
30-06-2017, 18:22
|
#19
|
Registered User
Join Date: Feb 2013
Location: Oregon
Boat: Seafarer36c
Posts: 5,563
|
Re: Wood, aluminum, or steel for new bowsprit.
Quote:
Originally Posted by Terra Nova
Channel is no good for a bowsprit.
|
If the load is right down the sprit, (compression load), round is the the strongest, lightest.
|
|
|
30-06-2017, 19:55
|
#20
|
Registered User
Join Date: Dec 2006
Location: Cruising
Boat: Privilege 39 Catamaran, Exit Only
Posts: 2,723
|
Re: Wood, aluminum, or steel for new bowsprit.
Steel or wood works for me.
I am not comfortable with any welding on aluminum if it is going to come under significant and repetitive loading.
|
|
|
30-06-2017, 20:33
|
#21
|
Registered User
Join Date: Jan 2017
Location: Saipan
Boat: Hunter Legend 40.1
Posts: 325
|
Re: Wood, aluminum, or steel for new bowsprit.
+1 for stainless tubing. Best overall strength and durability.
|
|
|
30-06-2017, 23:02
|
#22
|
Registered User
Join Date: Jun 2014
Location: Up the mast, looking for clean wind.
Boat: Currently Shopping, & Heavily in LUST!
Posts: 5,629
|
Re: Wood, aluminum, or steel for new bowsprit.
I understand the aversion to welding aluminum, at least in theory. But there are an awful lot of welded components on spars out there, most of which give no problems. Goosenecks, Shroud & Stay Tangs, Mastheads/Masthead boxes, Sheave boxes, Spreader Brackets, Hulls, & Keels, along with Rudders...
And if one wants to get technical about things, it's not great practice to structurally load welds in steel. But it's done all the time, & in many of the same applications as aluminum listed above, & more.
With things done right in terms of engineering & welding practice, there shouldn't be much in the way of issues, if any. And making things "modular" so that you needn't take off the whole sprit to have it modified or repaired. It's not as if it's rocket science, nor anything new.
__________________
The Uncommon Thing, The Hard Thing, The Important Thing (in Life): Making Promises to Yourself, And Keeping Them.
|
|
|
01-07-2017, 01:11
|
#23
|
Registered User
Join Date: Mar 2008
Boat: Cal 31 sloop
Posts: 33
|
Re: Wood, aluminum, or steel for new bowsprit.
If you are going to use galvanized steel tube, then you should know that the tube can not be completely closed while galvanizing. It needs a vent hole or two while galvanizing. You can then close the hole(s) with threaded fasteners or bolted on cover after galvanizing.
|
|
|
01-07-2017, 07:06
|
#24
|
Registered User
Join Date: Mar 2011
Location: fl- various marinas
Boat: morgan O/I 33' sloop
Posts: 1,447
|
Re: Wood, aluminum, or steel for new bowsprit.
Quote:
Originally Posted by Terra Nova
Channel is no good for a bowsprit.
|
Very clear statement. Sadly it is ignorant. The primary force on a bow sprite is resistance to bending up or down. Rectangular tube is stronger than channel of same thickness but not by a whole lot. More importantly, channel lets you avoid welds as connections can be easily through bolted. Flat bar could also work but is at a major strength disadvantage to channel or tube. Depending on the deck layout a 3/8" or 1/2" bar might be better than a much thicker cross section although he had been living with 9".
|
|
|
01-07-2017, 08:05
|
#25
|
Registered User
Join Date: Apr 2007
Location: Marina del Rey, California
Boat: President 43 Sportfish
Posts: 4,105
|
Re: Wood, aluminum, or steel for new bowsprit.
22--you seem to know a lot that simply isn't so.
If what you said were true (it isn't) you'd see spars made of channel and flat bar. This has nothing to do with deck layout. It has everything to do with using an efficient shape for compression loading.
__________________
1st rule of yachting: When a collision is unavoidable, aim for something cheap.
"whatever spare parts you bring, you'll never need"--goboatingnow
"Id rather drown than have computers take over my life."--d design
|
|
|
01-07-2017, 19:16
|
#26
|
Registered User
Join Date: Sep 2007
Location: Queensland, Australia
Boat: None at present--between vessels. Ex Piver Loadstar 12.5 metres
Posts: 1,476
|
Re: Wood, aluminum, or steel for new bowsprit.
Have you considered using fibreglass? It works fine for fishing rods--and it is strong and light.
I would be using glass and epoxy over a PVC core. Being hollow and corrosion free--wiring and screws etc should not cause problems, For the end I would use a Cranse iron cap of 316 or better stainless for the welded eye fixtures for bow stay and lower and lateral braces
|
|
|
02-07-2017, 11:08
|
#27
|
cat herder, extreme blacksheep
Join Date: Jul 2008
Location: furycame alley , tropics, mexico for now
Boat: 1976 FORMOSA yankee clipper 41
Posts: 18,967
|
Re: Wood, aluminum, or steel for new bowsprit.
why only consider teak?? there is also ipe and other hard woods that love sea water. use one of those. ipe is gorgeous and resists rot and insects.
my sprit will be constructed of huanacaxtle / ipe/perote wood from mexico, wherein i am cruising currently, at a pricing of less than 3 usd per foot. my 14.5 ft mizzenboom was 1200 pesos at 16 pesos to one usdollar. not bad shopping i think.
this is a beautiful and strong and resistent to all issues kind of wood.
get creative with your resources. they are out there.
donot forget that sprit is a very active part of your kinetic rigging and sail trims. also anchoring and other sprit involved usage. use strong hard materials designed for the purpose intended. good luck.
|
|
|
02-07-2017, 12:20
|
#28
|
Registered User
Join Date: Sep 2012
Location: Washington State
Boat: Colvin, Saugeen Witch (Aluminum), 34'
Posts: 2,296
|
Re: Wood, aluminum, or steel for new bowsprit.
Unpainted, aluminum pipe spars have the following qualities:
-Reasonable INITIAL cost.
-Lowest maintenance (none) of any conventional spar material. Therefore, lowest LONG-TERM cost.
-Very strong, tough.
-Quite light.
-Easily modified.
-May not match the aesthetics of an otherwise "wood accented" yacht.
A bit of taper can be built into the spar end by removing "slices" and re-welding.
|
|
|
02-07-2017, 21:10
|
#29
|
Marine Service Provider
Join Date: Dec 2010
Location: Little Compton, RI
Boat: Cape George 31
Posts: 3,182
|
Re: Wood, aluminum, or steel for new bowsprit.
Panope: what a gorgeous masthead! That is some nice looking design and work.
Thanks for those pictures.
__________________
Ben
zartmancruising.com
|
|
|
02-07-2017, 23:32
|
#30
|
Registered User
Join Date: Sep 2012
Location: Washington State
Boat: Colvin, Saugeen Witch (Aluminum), 34'
Posts: 2,296
|
Re: Wood, aluminum, or steel for new bowsprit.
Thanks, Benz.
|
|
|
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Rate This Thread |
Linear Mode
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Advertise Here
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
Vendor Spotlight |
|
|
|
|
|