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Old 07-11-2018, 14:31   #16
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Re: Back to the dreaded bowsprit material construction considerations

If it were I, I would leave the stainless alone--using mild steel hot dipped and galvanised properly--after drilling all of the holes for bushes slightly oversized. Once galvanised--the bushes will fit better.


Stainless in the common alloys has some problems--and in an area of high intermittent stress, when they do fail they do so without any warning.
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Old 07-11-2018, 14:43   #17
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Re: Back to the dreaded bowsprit material construction considerations

Quote:
Originally Posted by Eastward ho 24 View Post
Looks good rally good I'm in contact with the same place you went. Thanks. One more thing did you use 1/8 316 filler wire one pass?
I can't remember exactly but I think I probably used 3/32" 316l filler. Yes 1 pass.

I drew up the parts in Autodesk Inventor and had a shop in Pittsburgh laser cut them. I think the heavy parts were 1/2" 316l and the U shaped part was 1/4" 316l. Nice thing about getting things laser cut is they fit together perfectly esp the spinnaker crane which had nesting parts and I hate milling/cutting stainless. I ground the bevels with a grinder to fit.
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Old 07-11-2018, 14:47   #18
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Re: Back to the dreaded bowsprit material construction considerations

Looks good. My design is pretty straight fwd. Grinder and cut for me. Gonna have to get some 316l filler. Thanks
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Old 07-11-2018, 15:47   #19
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Re: Back to the dreaded bowsprit material construction considerations

You guys are far better welders than I am. Here is what I did, right or wrong.

Our 44’er has an 8’ sprit, 5’ over hang and 3’ in the deck. The origional (1985 build) was mild steel I think. It rusted through right where the anchor laid closest to it. That’s typical I think, any place two different metals come close you can get corrossion. Anyway, I cut it off. It was filled with some kind of weird material, almost like diatamatious earth. Light and fluffy. Not a clue what it was but presume it was meant to be a corrosion inhibitor.

The original sprit was 4”x4”x1/4” box section. It had no whiskers, just a straight stick. The teak platform and pulpit was wobbly as all get out. The anchor shanks came up through slots in the teak near the stem and always fouled the bob stay up or down.

I replace the sprit with 316 4”x4”x1/4” as original. However I added whiskers (2”x2”x1/4”) along the edge of the teak platform, solidly welded to the hull and the sprit. I moved the anchors forward and outboard so I could fit big new next gen anchors with their hoops. The bow rollers came out a little low but I adjusted by adding some starboard chafe guard for the chain, works a treat, like a second roller.

The platform and pulpit are now really steady making a great work platform. The anchors go up and down without fuss.

I fugure that whatever I lost in THEORETICAL strength I made up in adding the whiskers and by having greater confidence the damn thing won’t rust out again. Sure mild steel is stronger, but when you figure in losses due to corrosion, not so much.

It’s been a few years now and I’m happy with my work. All mig welded, fabrication in my basement then welded in place in a DIY yard.

I also added a 1/2” attachment at the cut water for an additional big shackel down there.
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Old 07-11-2018, 17:24   #20
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Re: Back to the dreaded bowsprit material construction considerations

it's been mentioned to get my acchors out past my headstay or was it Bob stay? Why is that for retrevial porposes?
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Old 08-11-2018, 02:49   #21
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Re: Back to the dreaded bowsprit material construction considerations

Does this help? See the old slots where the anchor shanks came up? That severely limits the size and type of anchor you can use. No next gen hoop anchors.
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Old 08-11-2018, 02:52   #22
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Re: Back to the dreaded bowsprit material construction considerations

Ahh ha yes I see what's the better wat have the roller right out on the end?
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Old 08-11-2018, 03:16   #23
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Re: Back to the dreaded bowsprit material construction considerations

There are two better materials than SS or mild steel that have not been mentioned here: Aluminum and composite. My first bowsprit I made from fiberglass and polyester resin. Worked perfect. A few years later, I seized the opportunity to make one out of carbon fiber. Lighter and more elegant. Either of them will outlast me, they were cheap and easy, and I don't worry about corrosion or keeping paint on.
Aluminum is a good choice as well: you can have all your tangs and fittings welded on, and as long as you use tef-gel on any fasteners, you'll not have corrosion problems. No need to paint: all the alloy on my boat is bare.
Stainless steel has certain uses, but very rarely is it a good choice on a boat.
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Old 08-11-2018, 03:36   #24
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Re: Back to the dreaded bowsprit material construction considerations

I could see aluminum. For me it would have been much more difficult to secure than simply welding to the steel deck.

But then there are a lot of different concerns between steel and glass boats. On a glass boat I would look hard at aluminum.
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Old 08-11-2018, 08:21   #25
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Re: Back to the dreaded bowsprit material construction considerations

.I don't have the equipment to weld aluminium or the knowledge but I agree the aluminium would be nice. I'm just not familiar enough with it's properties to know grade and thickness I would need.
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Old 08-11-2018, 08:43   #26
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Re: Back to the dreaded bowsprit material construction considerations

[QUOTE=Eastward ho 24;2757378]it's been mentioned to get my acchors out past my headstay or was it Bob stay? Why is that for retrevial porposes?

At anchor, your anchor rode would be in front of your bobstay. As the boat moves about at anchor, the rode is much more likely to not rub on the bobstay. If the chain comes out the middle of the bowsprit, it can't help but chafe on the bobstay.
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Old 08-11-2018, 11:44   #27
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Re: Back to the dreaded bowsprit material construction considerations

Although there is a pretty good aluminium shop right up the street from me. Any one have any idea what thickness and what grade of aluminium I would need to be equalivent to a .188 4x4" piece of ss
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Old 08-11-2018, 14:36   #28
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Re: Back to the dreaded bowsprit material construction considerations

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Old 08-11-2018, 16:32   #29
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Re: Back to the dreaded bowsprit material construction considerations

I can't seem to find any one who will electropolish a piece that s 8ft long. I got one quote from a place in Chicago that said 1500. I was really hopeing to pay about800 or less. If I hand buff and polish does that make it passive as electro polishing would? Does any one know a place that would electropolishing on the east coast ( I'm in NJ de MD area)? This kind of puts me back at square one if electropolishing is gonna be that much it's gonna be like 1000 for the material and 1500 to polish.i might was well either a. Go carbon steel and paint it do the whole thing myself . I've got awlgrip laying around. Or b. ( I think is best all around)Just have a shop weld up the aluminium for me. But I'm still not sure what grade of alu to use, if I have to anodized it after, and what thickness of alu 4x4 I'd need to be on par with 4x4x.188 SS as far as strength. God I hate over thinking everything.
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Old 08-11-2018, 16:55   #30
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Re: Back to the dreaded bowsprit material construction considerations

Look up Delstar in Houston, TX. I had them electropolish my anchor roller parts. They have a huge shop and do commercial parts so I'm pretty sure they have a tub big enough. Click image for larger version

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