Transom woods & Mahog prices?

[dmede]

Next step in the Maud & Emeline build is getting out the transom. Transom will be made up of two boards epoxied together with four bronze drifts through the joint. I need two 1 1/8” thick boards, one 9 ½”x40” and one 9 ½”x36”. I took a look at the H.Mahog at southern lumber today and found 8/4 for $14 b/ft. So that’s around 10 b/ft or $140. Seems high.

So first I need to know what price would be considered a fair price for HM on the west coast.

And second I’d like some ideas on other less expensive woods to use. I looked for Khaya but they didn’t have anything by that name. Atkin spec’s WO but I’d rather use something that will move less and be easier to work.

dave

[Spokaloo]

If you like color, Im exceptionally pleased with my purpleheart transom. Works like any other hardwood, not the best at taking epoxy but no worse than any other hardwood.

E

[pipefitter]

140.00 may seem alot for the lumber but it doesn't seem alot when considered as a transom of a boat. A boat transom in mahogany looks worth more than 140.00 when finished.What did the bronze drifts cost?

[pcford]

Khaya=African mahogany. Good wood. Cheap. Plenty around.

$14 for Honduras seems way high.

[Mrleft8]

Look at McBeath in SF. $14.00 is high, but H. Mahogany is getting expensiver, and expensiver by the minute. I got 8/4 H. Mahogany here at the "boutique" wood store for $9.00 bf last month.

[dmede]

McBeath and Global woods are my next stops.

I'm avoiding any kind of a laminated transom (especially with ply) because I want to stay more or less true to the plans and it's traditional building style. Hence the solid transom with drifts. But if it would save enough money I would laminate solid wood to get the thickness, and still use drifts as well. From the prices at Southern it didn't look like laminating 4/4 HM would get me any savings.

I choose HM more for it's purported working qualities and the fact that it wont move much more than my cedar planks, than for it's looks. It will be bright inside but painted outside. There's a 5% chance I'll leave it bright on the outside as well but I doubt it.

erster, would Utilie make a good transom wood? Does it move much?

[Thad Van Gilder]

Are you sure the H. Mahoghany wasn't $4 a board foot and not $14?

Maybe if it was $14 a square foot, that would be $7 a B.F. That is more reasonable.

-Thad

[Thad Van Gilder]

oh yeah, worse case scenario.

The local Woodcraft store has H. Mahoghany of various thicknesses for like $5 a board foot when its on sale.

-Thad

[DemiJohn]

I just bought sipo mahogany for $3.99 /BF for some interior structrural restoration. I can't testify to hardness but it's alot cheaper than Honduras and looks the same in my opinion. It's very easy to work with.

[pipefitter]

When I bought the H-mahogany for my Simmons 3 years ago,I got it in 5/4 for 4.96/bd foot by accident and the understanding nature of a kind importer/wholesaler. I looked recently and all that's available is 4/4 and 8/4 x 7' with the 4/4 going for 8.36/bd ft. I would still pay it for a bright finished stern being that ends up being one of the visual points of interest on a lot of boats. When it's all said and done,I don't think it would be the part that breaks you for 1 boat. Not to say not to shop around but after awhile,looking for a deal starts to cost as much.

[pipefitter]

Utile:

Product Type: Hardwood
Density: 660 kgm3 average
Colour: Light Brown
Texture: Medium
Durability: Durable
Permeability: Extremely Resistant
Origin: West and Central Africa
Species Name: Entandrophragma utile
Notes:
Also called Sipo (Ivory Coast) or Assie (Cameroon)

[Tom Mac]

Why not use white oak? stained sealed and varnished ? tough wood, I been using mahgoney on all brightwork, they get banged up dinked, and scraped. would oak be the better wood? thanks TomMac

[pcford]

Why not use white oak? stained sealed and varnished ? tough wood, I been using mahgoney on all brightwork, they get banged up dinked, and scraped. would oak be the better wood? thanks TomMac

white oak beside not being very pretty is not a good wood to finish bright

[orphan314]

while I find White oak very attractive, it is hard to keep it that way. as soon as any moisture makes it under the varnish it will blacken.
My real objection to using oak is its shrinkage/expansion. Radial (quatersawn) shrinkage is 5.6 percent and tangential is a whopping 10.5 percent. Wood that moves this much is hard to keep finish on and is even harder on fastenings. Checking also can become a major problem.

Utile has relatively high movement 4.6 percent and 6.4 percent respectively. Honduras Mahogany has by contrast 3% radial and 4.1 percent tangential shrinkage. This low amount of movement puts very little stress on glue joints , fastennings and finishes.

I'd hesitate laminating two different kinds of woods together unless thier physical properties are very similar. one side moving more than another will at the very least cause cupping and at the worst large checks and fractures. If you are strip planking , cold molding or glue lapstraking, you should definitely go with a very stable transom material as the planking won't expand and contract with the transom.

We (Bullhouse Boatworks) plank everything with northern white cedar not only because of its rot resistance and light weight but because its radial shrinkage is 2.2 % and its tangential is 4.9%. Nice and stable keeps the planking looking fair and prevents seams from openning during the winter. It greatly reduces maintenance.

14$/bdft is very high ... should be more like $8 -9 at that small volume. But it will be worth it to avoid future headaches as well as having a beautiful transom..... Dave

[dmede]

Thanks for all the input guys. I'm avoiding Wo for the reasosn stated above, moves too much. This boat is being planked in 3/4" western red cedar and riveted at the laps. Cedar is a very stable wood so I want a transom that will also be stable and move in concert with the planking.

$9 a b/ft sounds reasonable. Hopefully I'll finsd something at that price or lower when I call around tomorrow. Utilie looks like an interesting alternative but movement is an issue.

erster, your the only person around here that I've heard mention using the PL window sealant besides myself (as opposed to the construction adhesive). I'd like to hear more about how you've found it to behave, perhaps in another post. I've used it in place if Sika in a couple places and just used it to bed my stem knee to stem and I really like it.

[pcford]

If PL Contruction goo is polyurethane glue it is ____not____ appropriate for marine use. See discussion about Gorilla Glue.

[dmede]

No PC, I'm talking about PL window sealant, different stuff. And I don't use it as a glue, just as sealant or as a bedding that may need to be removed in the future. I like it, but I'm not going to get into a whole big discussion on the topic here, too devisive.

[pcford]

No PC, I'm talking about PL window sealant, different stuff. And I don't use it as a glue, just as sealant or as a bedding that may need to be removed in the future. I like it, but I'm not going to get into a whole big discussion on the topic here, too devisive.

Does it cure with the foaming bubbling action that Gorilla Glue does? If so, it's bogus as a true marine sealant.

It's amazing to me that Gorilla Glue is allowed to present itself as "100% waterproof." (If I recall their terms correctly.)

Any trip to a pharmacy will indicate how carefully the government regulates advertising claims anymore. Pure hokum is allowed. The Republicans have effectively gutted Federal overlook capability in this regard.

Thirty years ago this would not have been possible.

[orphan314]

Erster, your absolutely right that geography plays a big part in the choices and effectiveness of the materials that we use. When a proffessional boatshop makes a laminated transom, they choose woods with similar physical properties and ussually do a symetrical glue up. thus the inner and outer face might be Teak and the secondary wood would form a core. The stresses would be balanced just as they are in high quality marine plywoods.

Also , moisture will get into wood if the boat is left in the water for long periods of time. a little at first, enough to expand the wood and move joints so that more can get in etc. By realizing that eventually this will happen and using appropriate materials, we can assure the longest most trouble free life of the vessels we build (If that is what we wish)

10 years old is not even broken in for a well built boat. I just resold a A Herreshoff Watch Hill 15 that I built for a client in 1992. The client paid $30,000 in 92 and recieved $42,000 this spring for it without doing any more than normal maintenance on it.

It doesn't surprise me that your red cedar hull looks so good. With a radial shrinkage of 2.4 and a tangential shrinkage of 5.0, it doesn't move much, is very decay resistant and holds paint well. An excellent choice if I do say so myself. If it was a local wood for me I'd probably use it more.

Also ,do not confuse the hardness of cutting, sanding and bending of a particular specie with its strength or appropriateness .

[pcford]

Why don't you take this trash somewhere else, other than this discussion?

Gorilla Glue advertises itself as waterproof, yet it is not. I think this is significant. This problem is not trash my friend. Sorry if you don't care, erster. Others do.

I believe there has been a discussion regarding this adhesive on our host's magazine.

[pcford]

Whats the big deal with stick to discussing the glues, and leave the rest of the trash out?

Because I think it is significant that newbys be warned that "waterproofness" is an elastic definition these days. And the reason is political.

[pcford]

http://www.simplicityboats.com/PL%20Premium%202002.pdf

From the PL Premium Construction Adhesive data sheet, url above.
"At higher levels of moisture the cure rate will be faster."
"Too much moisture, such as standing water or a continous flow of water, will have the opposite effect and interfere with adhesion."

"Not intended for applications with continuous water submersion."

Sounds to me awfully like the manufacturers are recommending against using it in a boat.

I'll say it again, proper materials are cheap in the long run.

[pipefitter]

They aren't talking about that particular PL. They are talking about the window and door sealant. Amazing stuff actually.In a dry sailed boat it would work. The data sheet is also talking about the presence of standing water during initial cure. Moisture makes it cure but the bonding surfaces can't be saturated and noone will be building the boat in the rain or in a puddle. The boats would probably be painted which also adds sufficient barrier protection to the glue in a dry sailed boat that is going to be dry more than wet. Nearly like the climatic changes a house would be exposed to in the rainy season.The brown glue that is shown on the data sheet is more like liquid nails.

I also experience wood availability issues and boatbuilding supplies are from specialized lumber retailers and are few and far between.If I did stick my neck out and buy an ideal select,I doubt I would be able to get the same replacement 10 years from now when repair time comes rolling along. As it is,you may find 4 suitable boards in a stack on a good day and have to make many trips at different times to gather enough to do so. To take a salesman's word to even order what you want in any bulk form is a crap shoot and you will most likely be disappointed.

I end up just spending the $ for the H-mahogany for frames and such even if painted and DF for above. I am saving enough by building the boat myself.Especially as long as it takes when applying lesser priority hobby time to the task.

[Bob Smalser]

You're planking this boat with old-growth, riftsawn WRC, one of the most stable woods in the world. The transom should match the planking in stability as closely as possible to avoid cracking and fastener problems, and that limits you to H. Mahog or Khaya. Khaya isn't pleasant to work compared to Honduras.

You only need a few BF....spend the money if you have to. Bet we're not talking a 20-dollar bill between a good Doug Fir transom, which moves a lot for the cedar and can crack, and a Honduras transom.

[BrianY]

This may be crazy, but what about black cherry? It's durable, machines easily, holds fastenings well and glues well, and it's beautiful. Radial shrinkage is 4% and tangental is 7% - very similar to Honduras Mahogany (3% and 5% respectively).

On a more general note, can anyone tell me why cherry is not used more often in boat building? It seems to me that it might be an attractive and reasonabel substitue for mahogany in may applications - but I've been wrong about these things before. What am I missing?

[dmede]

Well, thanks again for all the input guys. I called MacBeath in SF, they have 8/4 HM for $11/bft and AM for $5.58/bft. That should be just fine.

I agree with the advice that it's not a large amount of wood and won't break the bank in the long run. I hesitated because my credo for this build is "affordable local woods". The HM seems like a slight extravagance in that regard but it really is the best choice for the transom.

dave

[landlocked sailor]

Cherry and Walnut would be good options. I think one reason they are not often used is there relative scarcity in coastal environments, at least in traditional boatbuilding centers. I have used it on my Windward 15



and on my Auk

Both have darkened considerable
Both are on plywood boats
Both boats are drysailed. Rick