Mast Support

Jan 10, 2011
289
Macgregor 25 Lake Lanier
Is the mast support a pine 2 x 4?
I was cleaning and noticed that there was mess at the bottom of the support. I started cleaning it up and found the mast support had been damaged by water collection.
It feels like a pine 2x4 but would like to know for sure.

Does anyone know for sure. I am pulling it out right now.
 

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Mar 15, 2021
51
Macgregor Venture 22 Brooklyn
Where ever possible on a boat I strongly suggest Black Locust. If I were replacing my mast support my first choice would be Black Locust and my second choice would be Oak.


It is harder than teak and more rot resistant than either teak or oak.
 
Mar 15, 2021
51
Macgregor Venture 22 Brooklyn
I have used black locust to rebuild an engine bed and for some other misc things on my Ericson 27. I have been very happy with it.
 
Jan 10, 2011
289
Macgregor 25 Lake Lanier
I replaced it with a knot free 2 x 4.
I was able to match the curves in the fiberglass and make it fit close to perfect. I think it is much stronger than the old support.
Time to recover the cushions and inspect the rest of the wood items on the boat.
 

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Likes: Will Gilmore
Mar 15, 2021
51
Macgregor Venture 22 Brooklyn
In compression most woods will be fine, but a pine 2x4 is far less rot resistant and less strong than Oak 2x4.
 
Jan 10, 2011
289
Macgregor 25 Lake Lanier
I agree. At the end of the season I think I will be replacing a few items. But this is the start of my sailing season.


I think I will do fine in coastal sailing in the Gulf of Mexico this spring and summer. Repair and replace items next winter.

I also need to find good marine plywood.
Cleat backing was just replaced.
 

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Mar 15, 2021
51
Macgregor Venture 22 Brooklyn
Marine ply is not really needed for anything on the interior. I would just go with good exterior grade and if I was worried about rot from water that may collect I would hit it with total boat penetrating epoxy.

The only reason I would even go with exterior grade is so the glue was not water soluble.
 
Sep 20, 2014
1,282
Rob Legg RL24 Chain O'Lakes
If you choose Oak, chose white oak instead of red oak. White oak is much more rot resistant. If you just wanted to use a 2x4, you could always use pressure treated.
 
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Mar 15, 2021
51
Macgregor Venture 22 Brooklyn
As I think I said before my go to is Black Locust for marine, especially structural. White Oak is my second choice.
 
Jan 10, 2011
289
Macgregor 25 Lake Lanier
Ok. I think that I will buy a black locust plant. Grow it for 4 years. Harvest a section without knots. Dry it for 18 months and replace the mast support. The pine might be attacked by that point in history and need to be replaced. I did not know that the black locust would grow in my environment(maybe). It would be a good experiment.

I like the marine plywood. I live outside of Atlanta, GA and the humidity attacks the wood even when I don't have a leak into the interior. Then it freezes and separates the wood. The marine plywood should have no voids.

The boat was created in 1981 and it may not need marine plywood. It may expire before the wood.

I used Oak on the hatch because I had no money and the Teak had been eaten by the weather.

I am ready for this season.
 
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Sep 25, 2008
291
1970 Venture by Macgregor 21 Clayton, NC
While the oak or locus may be more expensive, as stated, however any thing else may not hold up as well. The question then becomes do you want to go through the whole process of replacing it again and again, or do you want to do it once so you have time to repair the next problem.

As for the age of the hull, I got mine Venture (MacGregor) in 1970, and the hull strucurally is as good as when I got it. While it does not look that bad, it is at a point the deck in particular probably should be repainted.
 
Jan 10, 2011
289
Macgregor 25 Lake Lanier
I grew up on a ranch. We grew our own firewood. We built houses. When tools needed repair I went to welding school. When the tractor broke down I took autoshop and got a job as a mechanic. Then I turned 19. Now I teach engineering, great lab at work. Almost as good as the one at home.

I know that a boat is going to need repair. Over and over again.

I think it would be fun to create the part needed for replacement.

I think that I will buy a black locust plant. Grow it for 4 years. Harvest a section without knots. Dry it for 18 months and replace the mast support. The pine might be attacked by that point in history and need to be replaced. I did not know that the black locust would grow in my environment(maybe). It would be a good experiment.
 
Jan 10, 2011
289
Macgregor 25 Lake Lanier
Ok. Here is the problem.
The boat was built in 1981. Now with the support in place the Shrouds(side stays) are too tight. The backstay is too loose and the forstay if very tight.
I think I need to loosen the shrouds to allow the mast to lean forward.
I will be reading everything I can find.
I would appreciate any help.

Just read this and I think I will try it.
 
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Jan 10, 2011
289
Macgregor 25 Lake Lanier
I just put the boat in Aqualand Marina today.
Does anyone know the size pin is used on adjustment verniers on the shrouds?
I am guessing
Clevis Pins, 1/4 x 3/4
Just a guess.
 

srimes

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Jun 9, 2020
211
Macgregor 26D Brookings
Pine 2x4 (Or Doug Fir if available would be better). Cut to fit and treat with woodlife copper coat or equivalent. Paint with latex house paint or rustoleum enamal.
 
Mar 15, 2021
51
Macgregor Venture 22 Brooklyn
Pine 2x4 (Or Doug Fir if available would be better). Cut to fit and treat with woodlife copper coat or equivalent. Paint with latex house paint or rustoleum enamal.
How do you figure pine or Douglas Fir would be better than Black Locust? Do you know about black locust?


The wood is extremely hard, being one of the hardest woods in Northern America with a Janka hardness test of 1,700 lbf (7,560 N).[26] It is very resistant to rot, and durable, making it prized for furniture, flooring, paneling, fence posts, and small watercraft. Black Locust is a highly durable, organic wood product, that does not require chemical treatment to preserve its beauty for 50+ years.[27] Wet, newly cut planks have an offensive odor which disappears with seasoning. Black locust is still in use in some rustic handrail systems. In the Netherlands and some other parts of Europe, black locust is one of the most rot-resistant local trees, and projects have started to limit the use of tropical wood by promoting this tree and creating plantations. Flavonoids in the heartwood allow the wood to last over 100 years in soil.[28]

Yes it may cost about $8/foot, but for the mast step on a boat it is well worth that cost compared to the cost of pine followed by the cost of the preservatives needed, then the need to replace in any case. Use black locust on your boat and it will last longer than you.
 
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Likes: Will Gilmore
Oct 19, 2017
6,936
O'Day 19 Littleton, NH
In compression most woods will be fine, but a pine 2x4 is far less rot resistant and less strong than Oak 2x4.
Pine, as a general term, is a bit ambiguous.
Southern Yellow Pine, a class of hard pines that include Long Leaf, Short Leaf and Loblolly Pines, are known for their density and rot resistant. They may not be on the same level with Black Locust, but the weight savings may also be important. I knew a fairly successful boat builder who built a lot of boats out of SYP.

Longleaf Pine | The Wood Database - Lumber Identification (Softwood)

It is not a 2x4. It is close but not quite.
For those who may not be aware, the standard 2x4 that measures approximately 1.5"x3.5" at the building supply, is called a 2x4 because it is rough cut to 2x4 dimensions before put through a molder to its finish size and shape.

-Will (Dragonfly)
 
Sep 20, 2014
1,282
Rob Legg RL24 Chain O'Lakes
For those who may not be aware, the standard 2x4 that measures approximately 1.5"x3.5" at the building supply, is called a 2x4 because it is rough cut to 2x4 dimensions before put through a molder to its finish size and shape.

-Will (Dragonfly)
Not exactly. Its because it is cut nearly to size before it is dried. When it is dried it shrinks. Yes, it is planed after it is dried, but it starts out close to a a 2x4. This started with WW2 when there was a high demand for lumber. The wood was cut green and then shipped. Of course once it dried, we ended up with the odd size. The odd size became the target size.
 
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Likes: Will Gilmore
Mar 15, 2021
51
Macgregor Venture 22 Brooklyn
2x4 lumber has gotten smaller over the years. In my youth it was nearly 2x4. Desire for profits have seen it shrink because for most framing use it matters not.