Weekender keel

[Johnny Socko]

I am pricing lumber for the keel. The plans call for Pine, Fir, or other med softwoods.

How good is the urethane at keeping water out? If is as good as I was led to believe any wood or plywood is suitable to use in boat building.

At my local lumbar yard they suggested poplar over pine or fir for price reasons. (I was asking about clear pine).

And what is the difference between pine and fir? 

[Frank Hagan]

I am pricing lumber for the keel. The plans call for Pine, Fir, or other med softwoods.

How good is the urethane at keeping water out? If is as good as I was led to believe any wood or plywood is suitable to use in boat building.

At my local lumbar yard they suggested poplar over pine or fir for price reasons. (I was asking about clear pine).

And what is the difference between pine and fir? 

You can use poplar if you are going to trailer your boat.  A lot of the rules for boat building woods really matter if you are going to leave the boat in the water for a long time.  But most of us have our Weekenders living on a trailer, and they are in the water a few hours, and then back on the trailer.

Poplar isn't especially rot resistant, so its not a good choice for a keel on a boat sitting in the water.  But for a trailerable boat?  Sure. I would also recommend that you do not put fiberglass cloth over the keel.  The Stevenson's leave it unglassed, and in most cases that's the right decision.  If you glass it, as the wood shrinks and expands it will crack the glass and allow water to infiltrate and sit next to the wood, leading to rot even while its on the trailer.

Wood varieties vary by region, mainly due to shipping costs.  One thing you can do is find out what local wood is used for things like outdoor stair treds.  SYP or hard pine in the south, douglas fir in the west, etc.  There are several different varieties called "pine".  White pine is probably equal to poplar in terms of rot resistance, but poplar is a better choice than white pine in terms of hardness.

You also do not need clear lumber.  Most of us recommend using epoxy for laminating the keel.  If you get a 1x with a knot in it, knock out the knot, stick PVC tape over the hole, turn the board over and fill with an epoxy mixture.  Or, if the knot is sound and solidly in place, use epoxy to fill any holes that are there to prevent an area where moisture can accumulate and start the rotting process.  Epoxy is effectively waterproof, and easier to use than the powdered glue.  If you have already bought the DAP Weldwood, you can still use it, of course.  You can fill knot with it, but it is much harder to deal with if you need to sand it down to laminate the other layers to it.

I actually had a lumber yard rip green construction grade 2 x 12's on their giant bandsaw.  I wouldn't really recommend it for others, as the boards are not uniform thickness after doing that.  But it worked.

1 x 12 lumber is hard to find nowadays, but was common when the Stevensons first published the plans in the 1980s.  One other thing people have done is use a 1 x 8 and a 1 x 5 with the laminations staggered ... for the first layer, the 1x5 is on top and 1 x 8 on bottom, then the layer over it has the 1 x8 on top and the 1 x 5 on bottom.  The third layer staggers it like the first, so no two joints are next to each other.  As long as the joints between the woods are staggered, you can use butt joints without any fancy woodworking needed.  Epoxy, which is gap filling, is great for this kind of construction.

[John Weigandt]

Way back when I built mine (12 years ago)  I used the urea resin glue for most of the basic construction. BIG MISTAKE!!!    Where it has stayed dry.. the urea resin stuff has been fine, but it is by no means a waterproof glue for the long term. 

For the lumber, I found some nice 2x12 doug fir in long lengths at a real lumber yard, and paid them to plane it down to thickness.  I bet the guy had a tear in his eye, but it yielded better stock than I could find anywhere else. 

The keel has held up well, but only I suspect because gravity dries it, and it's protected from the elements.  A couple of years ago, I discovered water intrusion from the bowsprit bolt followed down the glue lines/ laminations, slowly leaching out the urea resin, and eventually soaking and rotting the stem.  I had to tear the stem apart and replace the wood, epoxying it back in.  This was water from rain and the elements... Water from above is by far your worst enemy.

I had similar issues back on the lower rudder bolt where I did the cross drill/bolt thing as per the plans.  DONT DO IT  I had water intrusion/ rot problems there too..  Fixed with cutting in new wood/ epoxy/ filler.

Any bolt your are putting into the wood, simply slightly underdrill, and screw the bolt into the wood with a liberal buttering of epoxy.  It will make it's own threads, seal, and can still be unscrewed if need be.

I did not encapsulate my keel with glass.. recipe for disaster... you will ding it, water will intrude, it won't dry, it will rot.

I did glass the hull with epoxy.. and it has held up well.

After learning about the versitility of epoxy and fillers,  I would NEVER use the urea resin glue again.

Get the free epoxy book online from system three  Very entertaining and educational. 

They are pushing all their "pre mixed" stuff nowadays, but you can get their catalog and still get the basic resin / fillers etc. 

John

Laminate that keel with epoxy. 

[Herschel Payne]

I read about one builder on this site who made his keel out of 2 sheets of 3/4" plywood. I was thinking of doing that but I've gone with white pine because of my easy access to it. Because it is relatively soft I'm thinking of putting a strip of metal on the length of it, sort of like a bang plate on a canvas canoe.

[Frank Hagan]

Herschel, it depends on whether or not you're going to beach the boat on rocky or hard shores.  Taking it on and off the trailer probably won't hurt the keel, even if it is out of a softer wood like white pine.  You can do a shoe; I seem to remember someone putting a full length brass plate on the bottom of the keel.  That's always something you can add after you see how well the keel holds up.

[PAR]

Plywood isn't the best choice for a Weekender keel for a number of reasons. Rolling sheer in the veneers, it only has 2/3's the longitudinal strength of solid lumber, but most importantly of all, the fasteners that hold it to the boat will be going into the end grain of the plywood and we all know how poor this type of grip can be.

There's a reason epoxy is hands down the favorite adhesive in the boat building industry. You can challenge this if you like, but there's a reason epoxy is the hands down favorite adhesive in the industry.

A "keel shoe" is a well used, time honored way of protecting your keel, regardless of how it's made, it's covering or material used. Metal has been the common material for decades, but now plastics have risen up and shown they can be superior in many ways.

Aluminum is easy to machine, but doesn't offer much protection, except abrasion. It'll dent and tear easily, but it's light and easy to drill for fasteners.

Steel will rust, but is tough and less likely to transmit impact damage to the keel. Stainless is an option as is galvanized, both are heavy. Stainless isn't fun to drill, but with good bits and practice, possible.

Bronze is a traditional metal, but expensive. It's fairly easy to weld, cut and drill. Brass is rarely used as it will corrode easily and is very weak, but cheaper then bronze. It machines like crap and you'll cuss the stuff quickly when working it with power tools.

HDPE, UHMPE, Teflon, etc. are super tough plastics that can be used in place of metals. They don't rust or corrode. They are really easy to work with tools, power or by hand, they are self lubricating and absorb impacts without transmitting the impact to the wood below. On the other hand they don't hold fasteners (threads) well, so have to be screwed or through bolted down (which a keel shoe is normally) and they don't stick well to most goops used as bedding sealants. This isn't a problem with the plastic, but special attention needs to be made at the fasteners to insure the bedding will stay put (counter sink the hole). Given a choice, I'll use these plastics over metal every time.

[Johnny Socko]

Thanks everyone for all the info.

Gwenivere is going to be a trailer queen.

I was leaning to a composite of dimensional lumber sandwiching plywood in the center. But now I think pine will do just fine. I don't see myself beaching it to often but I am thinking about a brass shoe (I can get it from work cheap). Or low density polyurathane (again cheap from work).

Thanks again,

John

[PAR]

LDPE would be better then brass, but make sure it's going to be stiff enough to offer some protection if you bang into a rock or a trailer bracket.

[Johnny Socko]

The LDPE I can get is 0.5" thick, but the problem is it is all in 3' lengths. (I see I spelled polyethylene wrong). The brass is not much better it is all 54" lengths.

[Al Stead]

I have worked with various polyethylenes over the years and plan to use it for the shoe on my plywood Weekender keel.  I would caution that if you live in a colder climate that you allow for expansion and contraction when attaching the poly to the keel.  I have found that this stuff contracts enough to bend screws or pull the substrate out of shape in winter. 

Us mushers have found a way around this when using poly for shoes on our sled runners.  We attach an aluminum dove tail rail to the bottom of the runner and slide the shoe on with that.  It can be difficult to machine the poly to the tolerances needed to hold it firmly in place, but you can order it ready made from a number of mushing supply sources.  The plastic comes in 8 ft lengths and isn't prohibitively expensive because we go through shoes pretty fast sometimes. 

Al Stead

[PAR]

Elongate the fastener holes or use especially over size holes with button head fasteners.

Do a test and stick a 12" long piece of of your polyurethane keel strip in the freezer for a week. Pull it out and measure it's length. Next, warm it in water water until it's 100 degrees and measure the length again. This will be the "spectrum" and an indication of how long your slots need to be. I'd guess they need to be about 1/2" long.

[Johnny Socko]

" Do a test and stick a 12" long piece of of your polyurethane keel strip in the freezer for a week. Pull it out and measure it's length. Next, warm it in water water until it's 100 degrees and measure the length again. This will be the "spectrum" and an indication of how long your slots need to be. I'd guess they need to be about 1/2" long."

I'll do that this weekend. I was planning to elongate the holes. But by how much was a crapshoot. Now I will know how much.

[Guest Ken Sutherland]

I have used HDPE as runners on sleds for ice fishing for years and it is incredibly good with respect to abrasion resistance.  When I first decided to build a Vacationer there was little doubt I wuold use it as a shoe for my keel but...

Using 30*F as a difference in temp which is an extreme difference in water temps but could happen for me in continental Canada (Winnipeg, MB) and 15' for a Weekender keel and 20' for a Vacationer keel

The Coefficient of Linear Thermal Expansion for:

Oak is 2.7E-6 in/in/F*

HDPE is 1.3E-4 in/in/F*

Oak would expand 0.01458" for a Weekender

                        0.01823" for a Vacationer

HDPE would expand 0.702" on a Weekender

                          0.936" on a Vacationer

That is closing in on a full inch for a 30* variation.

If I store my boat unheated my temps here in Winnipeg could easily range from -45F to 100F that is a difference of 145F  over a 20' keel the HDPE that is 4.52".  I'm guessing the HDPE would contract less per degree once it gets really cold but I think with my temp extremes metal might be the better option.

That said I sure would like to use HDPE if I could find a way to do it without problems.

Ken

[Al Stead]

The system that I mentioned before is called QCR or quick change runner system.  It consists of an extruded aluminum dovetail rail that is punched and countersunk to accept # 6 stainless screws every 5 inches.  They come in 8 ft lengths with a pair being sold per set.  The plastic is milled to pass over this rail and is held in place by a 1/4 pan head screw.  It isn't really quick to change this system as the name implies, but once the plastic is in place, it isn't going anywhere in a hurry.  The beauty of this system for our purposes, is that the plastic can expand or contract all it wants along the aluminum rail.  I haven't checked yet, but a pair of shoes which would do a weekender cut wide enough to cover the keel might be a custom job. 

With my plywood keel, and the Canadian shield passing under it, there is no way I am going to go without HDPE shoes on rails.  I have beaten the heck out of more of these things than I am comfortable remembering.  Even under the extreme torque of cornering a sled behind 20 lunatic huskies can't undo these things.  If anyone is interested in learning more about them, try looking through the equipment ads on sleddogcentral.com.

Al Stead

Old musher, new sailor

[Guest jennydinc]

I suggest you read books first on how to make a boat. There are lots of things to consider before you go to all the trouble of making a boat. It is not as simple as choosing which wood would work best. Also there are already modern materials you can consider like iron and steel frames. Mig Welding

[Johnny Socko]

Well I put 2-17 inch pieces in the freezer. They grew 1/16 inch from the freezer to room temp. I haven't warmed them yet, but I think they will grow the same amount.

My wife and I cut out the mainsail tonight, as soon as I learn how to post an image I will.

[Johnny Socko]

Here it is.

[Johnny Socko]

My wife got on me for only posting one pic.

[Frank Hagan]

Dogs love to help!

[Peter HK]

Dogs love to help!

Always there helping me- although now at 12 she sleeps a bit more and doesn't get in the way quite so often.