Simmons Sea Skiff - laminated stem

[towermikey]

I don't know what happened, but when woke up this morning I realized that I just started building my first boat. At least this is the story that I am giving my wife...

The boat is a Simmons Sea Skiff, and it appears to be an ideal first boatbuilding project. Thank you Wooden Boat, Ellis Rowe and Dave Carnell, you all have made the project appear doable...

So now to real questions. I am laminating a stem from quarter sawn 3/8 by 2 ¼” Brazilian mahogany. How much over bend should I add when laminating this?

While I recognize that If my stem is a half inch off the pattern, I am the only one that will know, but why not be close? My inclination is to give an extra ¾ of an inch at each end.

Also, the sandwich is really stiff. My only experience laminating is with fir, and thinner stock at that. Should I concern myself with the tension created by the quarter sawn hardwood and steam or wet the wood, followed by the appropriate drying time, or should I just go for it?

Towermikey

[pipefitter]

Why not just laminate it to over thickness so that the stem pattern fits it regardless of how it springs back.On my Simmons 18 I laminated it in the opposite direction.3 layers of 1x pine with the grains alternated,being it will have screws going through the lams from the planking. I also added 4-1/4x20 SS bolts to hold the sandwich together if the epoxy was to ever fail (yeah right).I dont see how you or anyone else would notice if the stem was off.I made mine 4ft and let it run wild past the sheer plank and cut it off after the sheer line was determined. Also,I leaned mine more forward than the plans because I wanted the boat to be more of an 18ft than a 17.It really isn't that noticeable.

[ 10-03-2005, 10:37 AM: Message edited by: pipefitter ]

[JimConlin]

The math gets a bit hairy, but I recollect that the amount of springback in a lamination will be about 1/n^2 of the bend, where n is the number of laminations. So if there are 4 laminations, the springback will be 1/16 of the bend.

Edited to explain what 'n' means above.

[ 10-03-2005, 10:55 PM: Message edited by: JimConlin ]

[pipefitter]

and one can always add another layer...so many variables such as wood grain,moisture content...what part of the tree it came from...air dried or kiln dried.It isnt going to make a noticeable difference on the boat...the plank lengths well exceed the stern and stem.

[ 10-03-2005, 12:01 PM: Message edited by: pipefitter ]

[towermikey]

Thanks, while that is such a simple solution, it eluded me...

[Granville]

Why are you laminating a stem? Can you not find stock wide and thick enough to do it from one piece?

[pipefitter]

Even if you could do it from one piece,a laminate would be alot less prone to warping and twisting/checking and alot of other little evils found in the quality of lumber today.

[Granville]

Even if you could do it from one piece even if you could?

its the only way the originals were built. and i think you have some kinda warped perception about lumber quality these days.

simmons made a goodly number of his stems out of plain old loblolly pine - wasnt nothing speacial about the lumber he used

[pipefitter]

I think you have a warped perception in general.Why do they use glue lams or micro lams to support a span of 40 ft when they could just toss a log up there? Engineered lumber is much more stable than solid.The guy obviously wants to make a laminated stem.Nothing wrong with it done that way. And you dont have any open endgrains when doing it that way other than on the ends.Now I guess if he wants to go out and hike and find a naturally curved piece of wood....alot of people used to do things alot of ways...doesn't mean there isn't better alternatives.They didnt usually make table tops out of a single slab of wood even if they could get one that big.Now you tell me why.
One other note...read the simmons info booklet where it says he switched to plywood planking when he couldn't find suitable planking material.

[ 10-04-2005, 12:36 AM: Message edited by: pipefitter ]

[Granville]

whatever. if you can convince him to build the boat out of glued up toothpicks more power to you

just trying to save the poor guy some needless work, but you just go on and be the expert if it makes you feel better ;)

[Paulyboy]

Another thing to consider, when forming lamination of wood you think may be too brittle, is to use a metal compression strap along the outside edge of the curve, so that it compresses and holds the wood in shape along it's entire length of lamination, instead of just using tension at the ends ala a spanish windlass contraption.

[pipefitter]

To some ppl it isn't work.Ellis Rowe seemed to enjoy doing more work laminating the stem of his Simmons shown in the last issue of Wooden Boat mag.Now how many of these boats has he built? Looks like a pretty nice boat to me.
Also,as you put solid lumber mixed with plywood,the solid lumber expands and contracts more than it's surrounding laminated members and sometimes will cause problems at the joints. It is better to use like materials and processes whenever possible.Doesn't take an engineer to realize this.

[ 10-04-2005, 10:27 AM: Message edited by: pipefitter ]

[Granville]

Also,as you put solid lumber mixed with plywood,the solid lumber expands and contracts more than it's surrounding laminated members and sometimes will cause problems at the joints must be why all there are now no longer any original simmons skiffs left around. all those solid stems, transoms, motor well, keels, chines frames and etc that he used ;)

I never will understand why folks feel the need to complicate boat building

its a boat not a spaceship or a piano case

[Granville]

Doesn't take an engineer to realize this.
doesnt take an engineer to design and buid a damn fine boat either.

take the Simmons skiff for instance ;)

[pipefitter]

Doesn't take a schooled engineer but whether or not Simmons or alot of others knew it,they were in fact engineers.

[JimD]

Whatever you do, don't over compensate for springback. With a laminated bend you'll never be able to force any of the bend out of it.

[pcford]

I think 3/8 is too thick for your glue lams. Try half of that.

With that said, like others I would try solid stock. I've done it both ways; chopping a rabbet is never fun. Cutting them in a laminated stem is less so.

In general, I try to stay away from epoxy as much as possible.

[Granville]

you make sense pc, and by the way the simmons has a false stem. no complicated rabbetting necessary
simmons didnt like un necessary complications. it slowed production and then he couldnt build or sell as many boats smile.gif

[pipefitter]

The guy obviously wants to laminate a stem.I dont recall anything in the post about doing a production run of boats.Actually,with a laminated stem,the rabbet could be built into it without chopping anything.I hear all this spouting about traditional construction,which is better etc. Yet I dont see any of the pro solid wood crowd hand cutting any wood from the logs and all the other traditional tools that it took to actually build a boat traditionally.Wonder how many boats would be built if all the fancy power tools were not available.Yuck to epoxy and all that other rot yet smearing tar or red lead on something is ok?What difference does it make? Traditional or new,the builders were/are still trying to preserve their precious wood with the best thing they could find.I can bet that alot of composite boat builders are more traditionally building boats by the sheer fact that they dont have a 5000.00 table saw or a super plunge router.Either way of building a boat if made by hand is still traditional in it's real sense of the word.Laminations have been around as long as there has been things built of wood,just not with epoxy maybe.If it didn't work it wouldnt be done.A bolted together 3 piece floor frame in a boat is still a lamination and an engineered part.Double thicknesses of staggered solid planks on a transom is also a lamination.Look around on any wood boat and quit being so narrow minded for the sake of argument.Let the man laminate his stem and his boat wont suffer a bit from it.

[Granville]

edited-

this is too much like argueing with oyster

[ 10-04-2005, 09:43 PM: Message edited by: Granville ]

[Granville]

sounds like an oyster ;)

[ 10-04-2005, 09:45 PM: Message edited by: Granville ]

[pipefitter]

Yeah..noted that you argue with many.Seems to be your forte and while I am here as to put your what Simmons himself did which has been the only fuel for your side of the argument,From the Simmons 20 plans I have in front of me, 2.Stem "Russ Ketterman told us that Simmons also made some of 3/4" plywood laminates."

[pcford]

The guy obviously wants to laminate a stem.I dont recall anything in the post about doing a production run of boats.Actually,with a laminated stem,the rabbet could be built into it without chopping anything.I hear all this spouting about traditional construction,which is better etc. Hmmm. I've done it both ways. I just prefer not working with epoxy, if it's possible. It's messy. Or at least it is when I do it.

[pipefitter]

Epoxy is some obnoxious stuff to use.If you call to order it on the phone it'll get on your ear.It's right up there with roof cement and paint or even drywall mud. It is a good glue though but I wish I could avoid it.Still better than polyester with the same mess but less the fumes.I like all kinds of construction of boats except the frp ones.I guess it all depends on what you are used to or have confidence in.Here in FL it is hard to find good wood in this overgrown cowtown I live in.It was difficult to even find suitable lumber for the strongback. Had to engineer on that piece as well.

[towermikey]

There is appropriate wood available and I may have saved a few bucks going the solid stem route but the other benefits of laminating out weighed the cost, ease and traditional benefits of a solid stem in my mind. My choice to laminate here was based on considerations for rot, strength and rigidity. While I appreciate sawn stems, laminating just made sense to me for this boat.

Well good or bad, my stem is glued up. There was nominal spring back and thanks to the advice of the posts, it actually fits the shape of the pattern!

Thanks for all of the oppinions; my band saw will make quick work of the rabbit, which I will clean up with a block plane. While the epoxy will ding up the blade a bit, it is a good excuse for me to practice my sharpening skills…

Thanks again,

Mike

[pipefitter]

Towermike,which version of the Simmons are you building? Plan on taking any pictures of the process as you go?

[towermikey]

I am building an 18, and pictures will happen as soon as I get a bit further into it. I am thinking of making some of the modifications that you did such as side decks and no frames. (This is assuming that you are building the 18 that is well documented on the Simmons site, and btw – the boat looks awesome!) I need to read up a bit more to satisfy myself that the boat would be sound without the frames. I am sure that this idea will elicit many comments, so send 'em out, the more info, the better...

[pipefitter]

The boat with the side decks definitely doesn't need the frames. It doesn't twist,flex or squash.I made the side decks larger than the plans because you can only step as far as the main deck side juncture and the inwhale is still quite a ways from your legs. I made them wider to house fishing rods underneath and even the reel handles are well behind the standing room.In other words,they dont come close to hitting your legs when walking by.I have 3 sets of frames used to attach the raised deck framing for and aft and the raised decks substitute the support that the thwarts would have given in the original design.I appreciate the nice compliments and just wait till yours starts taking shape.You'll find yourself staring at it alot.I just purchased the plans for the 20 and will be building that one as well. Can't have too many Simmons Sea Skiff's,ya know?You're going to have a blast building it.
I'm not committed to the console post yet.I built that on the slide in a hurry on company time out of scrap parts. It was mainly to set the height of the console and seat for research purposes.
I designed a nicer one for the Watts brothers fishing team. Ranger boats is going to be using it on their Banshee model but the idea for it came from them seeing pictures of my boat at work.

[ 10-05-2005, 09:43 PM: Message edited by: pipefitter ]

[JimD]

Epoxy is some obnoxious stuff to use...It's right up there with ...drywall mud Aw, c'mon. Epoxy isn't that bad :D

[pipefitter]

No,Jim...I guess mud is worse but I imagine epoxy has the potential to be.About midpoint thru the project,I wasn't getting any on me anymore.Let's just say when I first started...I have a pair of sneakers that should last as long as the boat.I don't get much mud on me anymore either but it took about 15 years to get to that point with that stuff.
I actually don't mind working with epoxy.I am just thankful it isn't polyester we are stuck with so I count my blessings.

[stevenj]

Originally posted by towermikey:
...I am thinking of making some of the modifications that you did such as side decks and no frames. (This is assuming that you are building the 18 that is well documented on the Simmons site, and btw – the boat looks awesome!) I need to read up a bit more to satisfy myself that the boat would be sound without the frames....on which site is this info located? I'd like to see that.

regards,
stevenj

[pipefitter]

It's located at http://home.earthlink.net/~tigmaster41/
It was suggested in the plans that with sheer decks that the boat could be built without frames. I used a wider sheerdeck than the plans called for so it is stiffer yet.
Plus it has knees under the sheer deck and a coaming rail on top. The boat is definitely sturdy.
I didnt opt to use the 1/4" ply but stayed with the 3/8ths throughout.I can lift each end of this boat by myself.I am no wooden boat expert but have vast experience in metal and wood fabrication and understand about gusseting and structural engineering. Most of it is common sense but I wouldn't take my word for it. There is alot of wood boat experts here in this forumn and as many varied opinions as to what works.I have full confidence in the changes I have made to this boat for my own sake.

[ 10-06-2005, 09:29 PM: Message edited by: pipefitter ]