MacGregorSailors.com

mastreb wrote:The economics of building a boat are just not there.

Before I bought my new boat, I spoke with two designers all the way through to the quote phase, and the bottom line is that it costs $20/lb. to build a "cheap" boat and $30/lb. to build a luxury boat, with the average one-off construction coming in around $25/lb.

The MacGregor costs $7.50/lb. unpowered, or 1/3rd as much as you could possibly build for. It is the least expensive production boat I've ever heard of. Completely fit-out and powered it's $12.50 lb.

A Beneteau costs $15/lb. well fit-out and ready to go.

Also consider that a stitch-and-glue plywood copy of a MacGregor is going to weight at least 2X as much. The boat will perform dramatically differently because of that extra weight, requiring a larger motor and more sail area to match the performance. You can't make a boat that weighs less than a MacGregor--Roger tried taking a layer of glass off to make La Perla Noir lighter and it suffered from cracking in the deck.

I've spent a lot of time playing with the idea of building, but there needs to be a revolutionary new building methodology or material in order to make one-off production cost competitive with mass production.

Taking an existing hull and rebuilding it to fit your specifications probably makes the most sense.

The following questions come into my mind:
- With the extra cost, maintenance, and weight of a plywood boat, what is it going to offer to attract customers as compared with a production fiberglass boat?
- The customization you offer is a nice feature, but how many people will choose a custom plywood boat over a low cost production fiberglass boat?

Back in the early 2000's I visited a boatyard in Costa Mesa, CA and they had an interesting way of building custom boats. Instead of using molds, they would setup mold stations out of plywood. Then they would fasten foam sheets to the stations to get the hull shape. Next, they would lay fiberglass on the "inside" of the foam sheets. Once the "inside" fiberglass cured, they removed the plywood stations, turned the hull upside down, and laid fiberglass on the "outside" of the foam.

Not sure if you can use this approach, but it seemed like a good way to get low volume, light, fiberglass hulls. Instead of having to store a mold, you would only need to store a stack of plywood stations. If you could make this work I think you could be more competitive against a production fiberglass boat.

I'd come up with a very simple method to build arbitrary one-off hulls with CAD accuracy that have less than an 8' beam:

1) Assemble a 2D CNC hot wire cutter from a CNC gantry (can be bought for about $4000) and a hot-wire cutter head.
2) Purchase bulk insulation styrofoam in 4x8 sheets and 2" thickness. You'll need 6 sheets per foot of LOA, or 156 for a boat the size of a MacGregor. Retail at home depot this is about $3000 worth of styrofoam, and it can be bulk purchased from a wholesaler for about half that.
3) Using a 3D cad package, slice your hull design into 2" profiles.
4) Cut each profile out in a Styrofoam sheet in order from fore-aft.
5) Build a box 4' hight, 8' wide on a flat concrete surface out of plywood and bracing 2x4s that is as long as your LOA. This should be very easy as plywood comes in 4x8 sheets that won't need to be cut. You'll only need to cut and screw 2x4s.
6) Stack the cut-sheet profiles in order in a 8' by LOA square box in 2" steps from stem to stern.
7) Working from one end to the other, fill the steps to smooth with plaster or bondo whatever, and sand smooth.
Spray in release agent.
9) Now you've got a form ready for typical gelcoat female mold fiberglass. Glass in your hull
10) Disassemble the box and break away the mold when complete. No need for lift-out.

Repeat for the deck liner an hull liners as necessary.

When I costed out this method a few years ago after thinking it up, I figured a hull similar to a MacGregor 26 would cost about $10,000 to make, including the cost of the CNC rig. This could be adapted to wider beams as well with some care.

Another advantage is you can use a 3D scanner to copy an existing hull shape from a boat in a yard or on a trailer, unless that hull has a design patent which you should check for. Handheld 3D scanners are available under $1000 now, and they can make very accurate CAD files of existing objects.

"Also consider that a stitch-and-glue plywood copy of a MacGregor is going to weight at least 2X as much."

The Hull weight has been calculated as 530 Kg. using a Finite Element Analysis Tool

I have posted the summary weight table for anyone interested. http://schoolroad.weebly.com/the-design-reasons.html


The build times are a big consideration. i will have a bit of a look at similar designs for an indication.

Fairing is indeed a big job.

plywood in marine grades is very expensive, too. no buildimg material is cheap.particle board, maybe.
oddly, old sailboats are cheap. maybe find an older design to update, like removing the finkeel from a light production boat like the Ranger. install ballast tanks, and a big outboard?
Ix

Dnomyar wrote:"Also consider that a stitch-and-glue plywood copy of a MacGregor is going to weight at least 2X as much."

The Hull weight has been calculated as 530 Kg. using a Finite Element Analysis Tool

I have posted the summary weight table for anyone interested. http://schoolroad.weebly.com/the-design-reasons.html


The build times are a big consideration. i will have a bit of a look at similar designs for an indication.

Fairing is indeed a big job.

530 kg = 1168 lbs. That's half the weight of the M boat. From plywood??? Am I missing something here?

Dnomyar wrote:"Also consider that a stitch-and-glue plywood copy of a MacGregor is going to weight at least 2X as much."

The Hull weight has been calculated as 530 Kg. using a Finite Element Analysis Tool

I have posted the summary weight table for anyone interested. http://schoolroad.weebly.com/the-design-reasons.html


The build times are a big consideration. i will have a bit of a look at similar designs for an indication.

Fairing is indeed a big job.

I imagine there are many assumptions made when performing that analysis. I mentioned earlier that I was about to build a very similar boat, the Didi 26 from Dudley Dix. This is about a 2200 pound boat. Add a motor and still less or maybe comparable to my

RobertB wrote:

Dnomyar wrote:"Also consider that a stitch-and-glue plywood copy of a MacGregor is going to weight at least 2X as much."

The Hull weight has been calculated as 530 Kg. using a Finite Element Analysis Tool

I have posted the summary weight table for anyone interested. http://schoolroad.weebly.com/the-design-reasons.html

.

I imagine there are many assumptions made when performing that analysis. I mentioned earlier that I was about to build a very similar boat, the Didi 26 from Dudley Dix. This is about a 2200 pound boat. Add a motor and still less or maybe comparable to my

When I got that estimate, I also did a manual check. That came out both came out pretty close. The FE tool is great in that it can add every square centimetre of every frame and hull, and multiply it by the marine ply weight.

A very similarly dimensioned design comes in at [Weight, dry w/o engine = 2500 lb] - the http://bluejacketboats.com/bluejacket-28/

By comparison, on our theoretical weight table, the equivalent total is 1303 kilo, with permanent sailing ballast (2880 pounds)

Dnomyar wrote:"Also consider that a stitch-and-glue plywood copy of a MacGregor is going to weight at least 2X as much."

The Hull weight has been calculated as 530 Kg. using a Finite Element Analysis Tool

I have posted the summary weight table for anyone interested. http://schoolroad.weebly.com/the-design-reasons.html


The build times are a big consideration. i will have a bit of a look at similar designs for an indication.

Fairing is indeed a big job.

Yes, but that's your hull only. The entire MacGregor 26M weighs just 1020 kg + 140 kg of internal ballast. A total weight estimate of 2000 kg is likely a bit high.

I just checked the Dudley Dix design Robert mentioned, which is a 25 foot sailboat in plywood, and it weighs 1500kg. So I may be a bit high.

I really like your design idea, there's just no way to make it as light as a MacGregor and owners would need to be prepared for how much weight matters in terms of handling is all I'm saying. It's more power required, larger engine, etc. Not a deal breaker by any means.

In my various "self-built power sailor" machinations I've determined that I would do the following three things that you might want to consider, especially since they will fit your hull design very easily:

1) Forward mast, gaff rig, and bow sprit. Move your mast 5 feet forward, shorten it, and use a Gaff rig mounted on a harken batt car track (Get the batt cars larger than AA however so they'll actually retain). Using a car track willl allow you loft the gaff on a car very easily. I'd use a car on the boom as well, and a downhaul (vang) to tension the mainsail. Using a gaff rig will allow you to loft a lot more mainsail area with a lower mast that can then simply fold to aft at the tabernacle without ever needing to be unstepped for trailering.

2) Use a bowsprit. With the Gaff rig, you'll want to move the headsail forward, and bowsprits are an easy way to do that.

3) Use dual asymmetrical foil "leeboards" in inside daggerboard trunks port and starboard. This is the concept of a leeboard (one for each side of the boat) but they are inside the hull in daggerboard trunks. Putting them inside the boat just slightly eliminates the surface turbulence drag associated with leeboards, which is their only performance detractor, and allows you to use asymmetrically shaped boards that can nearly eliminate leeway (already shown with foil leeboards). Having them inside trunks eliminates the undesirable look of traditional leeboards, and this setup eliminates the center daggerboard trunk that dominates the interior of small cruisers with them. It's better in every respect excepting a little extra work to make the daggerboard trunks. You do have to change boards on tacks as well, but you can put the boards on a loop line that will allow them to counter-balance one another and make easy work of it.

Just some thoughts.

I would avoid any additional centerboard trunk inside the boat like the plague. With plywood they are hard to Install and maintain. I think nothing of a bit of mashed gel coat inside the centerboard trunk from my grounding, but in plywood I'd be worried if I thought the glass skin had been compromised. And no way to repair it easily.
When I contemplated self build, I was going to make the trunk wide enough to get a grinder inside, then use an insert to secure the foil. That takes up a lot of inside space but allows for repairs.
There are good reasons why many place the leeboards outside the hull.
Essentially I'm done with wood though. And I love it really. Just not right for me any longer. I don't have the time or desire to maintain it.
How about a glass hull and deck with lots of room for customization via "modular" system designed with the aid of computers?
Think ikea but for boats. A larger Mac like hull, with a lot more interior options and a (probably) much higher price point might be viable. As people mature and hopefully increase wealth they move up to the lux version of the concept they've enjoyed for years. The seaward is sort of like that I guess but your boat would be lighter cooler cheaper and only need a two axle trailer
Ix

I was thinking that some components would be best built out of Glass - like the daggerboards, and maybe even the trunks.

I would expect a few people would like the option of either a central daggerboard, or a folding centreboard. Maybe these could be an option on the plans ?

I emailed a couple who built one of the Bluebeard 28 foot motor cruisers, and they said it was a long build. I guess the time saving that a CNC kit would provide could be a solution.

Lots to think about

EZ wrote:
The following questions come into my mind:
- With the extra ... maintenance, .. of a plywood boat, what is it going to offer to attract customers as compared with a production fiberglass boat? .....

The maintenance side of things is something that I have been pondering over for a while.

From my experience - it dawned on me that this is actually not that much of a problem.

The Mac I once owned, was parked on the hard stand next to another FG yacht. I was polishing the Gelcoat on my boat one time, after having it moored against an old tyre at a wharf. The carbon black was coming out a bit, but the grey patch stayed forever. The owner of the other boat came over, and said 'are you doing any good'. I told him I was having limited success, and he showed me a damaged patch that he had repaired some years ago, and talked about the difficulty of matching the coats.

When you think about it - hull appearance for resale value and owner satisfaction is a huge factor. Now, think about how tired gelcoat gets after a few years. Its impossible to match damage exactly, and you know how suspicious people get with a resprayed fiberglass hull.

I compare that scenario to the time when I sailed smaller wooden boats ( not even glass coated ), and the recent repairs I did on a large wooden epoxy covered canoe I own. Each of them got restored to factory finish every three or four years.

I have noticed that when you have a pristine boat, that is expensive to keep looking good, that a lot of the fun of taking it out goes when you think about the potential damage each trip could do.

Whereas, if you have a hull that can be brought back to a high standard fairly easily, then a lot of the emotional pressure is taken off. Likewise, if you ever come to sell a boat, being able to bring it back to excellent finish is a huge bonus.

What do you think ?

That's one of the things I like about gelcoat. Even Macs with their topside black which fades to grey in a year are easy to restore. I did nothing to my boat for three years, then had a gelcoat restoration guy go at it for one day for <$1000 and it's back to factory shiny new.

My 30 (now 45 yo) Columbia Sabre stayed white. A bit chalky, but easily restored. There was no hiding the bullnose fiberglass repair though.

Dnomyar wrote:

EZ wrote:
The following questions come into my mind:
- With the extra ... maintenance, .. of a plywood boat, what is it going to offer to attract customers as compared with a production fiberglass boat? .....

The maintenance side of things is something that I have been pondering over for a while.

From my experience - it dawned on me that this is actually not that much of a problem.

The Mac I once owned, was parked on the hard stand next to another FG yacht. I was polishing the Gelcoat on my boat one time, after having it moored against an old tyre at a wharf. The carbon black was coming out a bit, but the grey patch stayed forever. The owner of the other boat came over, and said 'are you doing any good'. I told him I was having limited success, and he showed me a damaged patch that he had repaired some years ago, and talked about the difficulty of matching the coats.

When you think about it - hull appearance for resale value and owner satisfaction is a huge factor. Now, think about how tired gelcoat gets after a few years. Its impossible to match damage exactly, and you know how suspicious people get with a resprayed fiberglass hull.

I compare that scenario to the time when I sailed smaller wooden boats ( not even glass coated ), and the recent repairs I did on a large wooden epoxy covered canoe I own. Each of them got restored to factory finish every three or four years.

I have noticed that when you have a pristine boat, that is expensive to keep looking good, that a lot of the fun of taking it out goes when you think about the potential damage each trip could do.

Whereas, if you have a hull that can be brought back to a high standard fairly easily, then a lot of the emotional pressure is taken off. Likewise, if you ever come to sell a boat, being able to bring it back to excellent finish is a huge bonus.

What do you think ?

Dnomyar,

Years ago I used to crew on an old Brigantine rig charter boat. It was all wood construction. What I remember was that there was a lot of worry whenever it rained about keeping the boat protected from rot. When I think of maintenance as compared to a production fiberglass boat, this is what comes to mind.

You sound like you have a lot of boat building experience (more than me for sure). So repairing rot may be easy for you. Will your market see it as being easy?

The big question is, what is the perspective of your market? Especially when Tattoo is claiming fiberglass is almost maintenance free ( I don't agree with this btw). Are you trying to sell to those who favor wood boats? To me these people seem to like a more traditional looking boat. So I am not sure what your market would be.

IMHO, market is something I think needs to be worked out before you pour a lot of resources into this project.

Plywood boats today are closer to fiberglass boats than traditional wood boats. A boat such as I described earlier, the Didi 26, is made of wood but the wood is encapsulated in epoxy and fiberglass. Paint is there primarily to protect the epoxy but also for looks. A boat such as this is targeted at the home builder. Fiberglass requires a mold, plywood just a frame type form. Built right, rot is not an issue. Build right means carefully sealing all holes for hardware. Care is not much different than our boats - just needs a coat of paint a bot more often for looks. The market is the home builder (although plywood is a very superior boat building material, just not well suited for production runs).