Chainplates & Rigging

[Neil Gordon]

[quote="Stan W."]... it is unclear whether his model is based on a masthead or a fractional rig. It also does not appear that the possibility of a big overlapping genoa was considered at all./quote]

First published in 1904.

It's not clear that he's talking about Marconi rigs, either. There would be significantly more load on lowers with a gaff rig, I suspect.

Stan, both a storm jib and an overlapping genoa attach to the boat at the same points: masthead, stem and winch (with some shared load at the block). I get the relative stress on those points as jibs get bigger and mains get smaller. Big genoa and small main would stress the uppers more? The mast would be in compression, with the lowers just there to keep it from folding in half.

[BubbaThePirate]

Fascinating and pertinent thread. I'll be doing the same thing next Summer on my CD28.

Jonathon - keep us posted and I'll do the same. I've also begun the radiused and glassed gunwhale a la Fenix. I plan to replace my stanchion bases and do something similar to Fred's 'floating toe rail.' What other ideas from Fenix or elsewhere are you doing?

Good Luck,
Todd

[mgphl52]

Fascinating and pertinent thread.

Very much so! When funds allow, we want to pull Tranquil's main and mizzen masts for rewiring (with pvc conduit), possibly converting to internal halyards on the main mast and replacing all standing rigging. Some of her current was rigging was replaced not too long ago, but she has both Sta-Lok and Norse fittings. We want to make them all the same type for easier repairs and simpler spare parts inventory. Though her design displacement was 14~15,000, she tipped the lift scales at 22,000 when we launched her last year. We may even up the lowers to the same size wire as the uppers, again to simplify spares.

[hilbert]

As Todd suggested, it would be nice to keep the thread going and to exchange updates.

I will need to remove the toe/rub rail to repair the deck. It appears to have been deformed and cracked on the starboard side, by the pull on the backing plate. I will remove the old shroud padeyes and do my best at repairing the deck and creating a smooth hull/deck seam. I like the bulwark and large rub rail that Fred added and I am seriously considering doing the same. Does anyone have any suggestions for the selection of wood? I am looking for inexpensive solutions, maybe materials used in home decking.

I will re-bed the stanchion bases. Fred found that some of the through hull penetrations went through the core and were not properly sealed. I replaced the core of the cockpit floor over the summer and it was an unpleasant experience.

As far as the chain plates, maybe someone can benefit from my experience. I decided to keep the original wire sizes, although I may reconsider if I find that I need to replace the tangs on the mast. I purchased stainless 316L bars for the chain plates and 304 for the backing plates online from Metal Supermarkets:

Qty 2, 3/8â€

[BubbaThePirate]

WOW! Great post, thank you. You have given definition to a swath of vague concepts I've been stewing on. I will be recoring my cockpit floor as well.

This months Good Old Boat has an article about plastic deck lumber handholds. That might work for the Floating Toe Rail.

Thanks again. I've got a few project pix I can post when I get home next week.

Todd

[fenixrises]

Hi all,

The wood for the bulwarks and rubrails could be what I used. That is 1" net X 5&1/2" net long leaf yellow pine. It is treated and goes by the trade name of "Yallow Wood".

However there is one problem with the wood. The treatment soaks into the wood completely and makes it basically impossible to use glued scarf joints. Mine held together long enough to assemble but in the long term all the joints started to fail.

As a substitute it would be better to use untreated wood. Quarter sawn Douglas fir would also be a good wood to use. As long as neither wood is left standing in fresh water it will last a long time.
Douglas fir was used as deck planking on west coast work boats. And long leaf yellow pine was used extensively on the east coast for hull planking. The "Spray" was replanked with this wood. Back in the day it was considered one of the best planking woods available.

A simple coating of paste wax twice a year will promote longevity. Apply it liberally and do not wipe it off.

The "Plastic" decking is certainly impervious to anything. But I do not know how you would glue it to make lenghts more than 16'. It is also much heavier than wood and about 4 times as expensive.

A possibility for the bulwarks would be to make the joints overlaps without glue. If you put on exterior chainplates and want the bulwark as well you will need to do this to get clearance between the bulwark and the turnbuckles. I had to "hog" out a fair amount of the bulwark rail at each chainplate to be able to fit the turnbuckles. Additionally I had to drill holes in the bulwarks to be able to insert the turnbuckle pins.

Here is a rudementary keyboard example of what I mean.
Inboard
xxxxxxxxxxxxv Overlap area through bolted
xxxxxBaseO=====================O <Stantion Base
===========xx _xxxxx_xxxxx_xxx=================== Rail
Chainplates
Outboard
The x's are type fillers.

Don't forget that I added one stantion to each side of the boat so that there is only about 5' between stantions.

Take care,
Fred

[BubbaThePirate]

Thanks, Fred! I would have been tempted to do the bulwarks first as the mast and rigging are near the end of my punch list. It will be better to get the rig up to obtain said measurements. I have a friend in the Geometric Dimensioning and Tolerancing business. I didn't think I was going to need his help on the boat. :o)

Fair Wnds,
Todd

[hilbert]

As a substitute it would be better to use untreated wood. Quarter sawn Douglas fir would also be a good wood to use. As long as neither wood is left standing in fresh water it will last a long time. Douglas fir was used as deck planking on west coast work boats. And long leaf yellow pine was used extensively on the east coast for hull planking. The "Spray" was replanked with this wood. Back in the day it was considered one of the best planking woods available.

Been working on this for a while . . .

I found a local source for reclaimed 5" wide, long leaf yellow pine boards.
While pretty, these old floor boards are like iron with a low moisture content.
I'm not sure that I will be able to bend them to the brackets along the curve of the deck.
Should I pass on these and continue searching for greener wood?

[tjr818]

My gut feeling is that you could bend the yellow pine. The rubrail and toe boards were bent around those curves and that teak is stiffer that yellow pine.
Here is what the Wood Database has to say. Bear in mind that they are talking about modern Longleaf pine, not the older good stuff that you are talking about.

Longleaf Pine
Longleaf Pine (Pinus palustris) Common Name(s): Longleaf Pine Scientific Name: Pinus palustris Distribution: Southeastern United States, though also widely grown on plantations Tree Size: 100-115 ft (30-35 m) tall, 2-3 ft (.6-1 m) trunk diameter Average Dried Weight: 41 lbs/ft3 (650 kg/m3) Specific Gravity (Basic, 12% MC): .54, .65 Janka Hardness: 870 lbf (4,120 N) Modulus of Rupture: 14,500 lbf/in2 (100.0 MPa) Elastic Modulus: 1,980,000 lbf/in2 (13.70 GPa) Crushing Strength: 8,470 lbf/in2 (58.4 MPa) Shrinkage:Radial: 5.1%, Tangential: 7.5%, Volumetric: 12.2%, T/R Ratio: 1.5 Color/Appearance: Heartwood is reddish brown, sapwood is yellowish white. Grain/Texture: Straight grained with a fine to medium texture. Endgrain: Large resin canals, numerous and evenly distributed, mostly solitary ; earlywood to latewood transition abrupt, color contrast high; tracheid diameter medium-large. Rot Resistance: The heartwood is rated as moderately resistant to decay. Workability: Overall, Longleaf Pine works fairly well with most tools, though the resin can gum up tools and clog sandpaper. Longleaf Pine glues and finishes well. Odor: Has a distinct smell that is shared among most species in the Pinus genus. Allergies/Toxicity: Working with pine has been reported to cause allergic skin reactions and/or asthma-like symptoms in some people.

Teak
Teak (Tectona grandis) Common Name(s): Teak, Burmese TeakScientific Name: Tectona grandisDistribution: Native to southern Asia;Widely grown on plantations throughout tropical regions of Africa, Asia, and Latin America.Tree Size: 100-130 ft (30-40 m) tall, 3-5 ft (1-1.5 m) trunk diameterAverage Dried Weight: 41 lbs/ft3 (655 kg/m3)Specific Gravity (Basic, 12% MC): .55, .66Janka Hardness: 1,070 lbf (4,740 N)Modulus of Rupture: 14,080 lbf/in2 (97.1 MPa)Elastic Modulus: 1,781,000 lbf/in2 (12.28 GPa)Crushing Strength: 7,940 lbf/in2 (54.8 MPa)Shrinkage: Radial: 2.6%, Tangential: 5.3%, Volumetric: 7.2%, T/R Ratio: 2.0Color/Appearance: Heartwood tends to be a golden or medium brown, with color darkening with age.Grain/Texture: Grain is straight, though it can occasionally be wavy or interlocked. Coarse, uneven texture and moderate to low natural luster. Raw, unfinished wood surfaces have a slightly oily or greasy feel due to natural oils.Endgrain: Ring-porous or semi-ring-porous; large to very large solitary earlywood pores, medium to large latewood pores, few; solitary and in radial multiples of 2-3; tyloses and other heartwood deposits (light-colored) common; medium rays visible without lens, spacing normal; parenchyma vasicentric, and banded (marginal), with bands sometimes wide enough to enclose entire earlywood pores.Rot Resistance: Teak has been considered by many to be the gold standard for decay resistance

[John Stone]

Fred,
Great to hear from you. I hope you are well and enjoying life in the Far East.

For All,
I think there is some misinformation here. I built a complete new taller rig for my boat...a lighter, but stronger design with double spreaders and running backstays. I did a lot of research. I used Skene's as well as Chappelle's "Yacht Design and Planning", and also Brion Toss' book "The Rigger's Apprentice. I also hired Brion to consult on the rig. A friend of my, a spar engineer, did a lot of design work and initial fabrication and worked the engineering calculations. I built the rig. Brion also looked over all the design work and in fact had me change the location of the mast fitting for the forestay. I mention all this to caution anyone that is planing on changing their rig to do their homework. Masts and supporting rigging are carefully engineered and while all the CD rigs, so far as I know, are very strong Bermuda rigged boats experience significant loads--much more than gaff rigs. So be careful.

I am not discouraging anyone from doing their own work. I am all about boat owners doing all the projects they can manage to include maintaining or changing the rig or whatever it is you want to do. But rigs are a life and death kind of thing and should never be taken lightly.

From Toss' book, which I highly recommend, Chapter 5 Standing Rig Design and Materials:
-Single spreader rig with one set of lowers: 45 percent load on uppers and 55 percent on lower (60 percent on lower if aft of the CL).
-Single spreader rig with two sets of lowers (for and aft lowers): 45 percent on upper and 32.5 percent on each lower.

Brion's book has lots of information about how to determine rig loads, etc. He also recommends making the rigging the same size. More for convenience than engineering requirements. It makes sense because different wire can mean different turnbuckle sizes etc. All the standing rigging on the Far Reach is the same size except for the bobstay which is a bit larger.

I have spoken to Yves Gelinas many times. We talked about his dismasting in the Southern Ocean on Jean du Sud. He converted his single spreader rig to double spreaders. My recollection is he increased the wire size of the lowers but left the fasteners on the chainplates the same size and it was the fastener or the nut that failed, not the wire or tangs.

To me the most important thing regarding the rig isn't increasing the size of the wire but to making sure you inspect the rig frequently. All of it. From top to bottom and replace the wire, tangs, and especially those darn strap toggles at the first sign of fatigue or corrosion. That is not to say that increasing the size of the lowers is not a good idea. I defer to Fred and others more familiar with the CD 28 than I am.

Keep in mind that all stainless is not created equal. It's not just the difference between 304 and 316, its the quality of the stainless steel and how it was made and the QC that accompanied its manufacturing.

This is a really good and useful thread for owners of the CD 28 but there is no substitute for hitting the books and learning all you can before you make changes.

[hilbert]

John, great information as always, however it appears that I have created confusion by reviving this old post.
I did so because I am attempting to tie up loose ends from 2010, with the bulwarks.

I found long leaf yellow pine that Fred recommended in this thread, a long time ago.
They are very dry reclaimed 5.5" floor boards and I am concerned that I will not be able to bend them around the curve of the deck.

You have recommended Ash as a possible lumber for bulwarks.
Given your experience, do you think that I should pass on the old pine and continue to look for newer ash with a higher moisture content that would be easier to bend?

Thanks,
Jonathan

[hilbert]

My gut feeling is that you could bend the yellow pine. The rubrail and toe boards were bent around those curves and that teak is stiffer that yellow pine.

Tim, you may be correct, however this Heart Pine is extremely hard, strong and stable.
Also, the teak strips on the CD28 were about 1 square inch compared to the 3+ square inches for the reclaimed boards.

[John Stone]

John, great information as always, however it appears that I have created confusion by reviving this old post.
I did so because I am attempting to tie up loose ends from 2010, with the bulwarks.

I found long leaf yellow pine that Fred recommended in this thread, a long time ago.
They are very dry reclaimed 5.5" floor boards and I am concerned that I will not be able to bend them around the curve of the deck.

You have recommended Ash as a possible lumber for bulwarks.
Given your experience, do you think that I should pass on the old pine and continue to look for newer ash with a higher moisture content that would be easier to bend?

Thanks,
Jonathan

Well, I feel silly. Trying to do too many things at the same time.

If they are flat (plane) sawn boards I think they will bend. Long lead yellow pine is fantastic wood. Some say better than teak.

Really hard wood like ash can probably be milked to 3/4-7/8” thick. I think they will bend. If they are quarter sawn maybe not.

Ash is good. Mahogany. Iroko. And the pine is good if plane sawn and if it does not have knots. In fact they should all be flat/plain sawn.

Ash will be the least expensive probably.

Does that help.

My apologies for reacting to the thread without reading more carefully.

Best.