Marblehead Pond Yacht by Michael_A - 1:1 - RADIO - 1940s design by J Selmer Larson

[Michael_A]

Hello everyone,

 

I started this model a few months ago and am creating this build log (my first) so I can show the progress to date and get advice moving forward.  I have to say I am feeling a little nervous!

The boat is a 50" model yacht of the Marblehead class. This class was started in the Depression era when, like now, people had more free time on their hands. These models were designed to sail in ponds (like the one in Central Park in NYC). Initially they would sail on their own and be redirected by the owner at the edge of the pond, with a stick. Now, they are mostly radio control. I'm more interested in building than sailing so we'll see how far I progress in that area. 

 

The design is by J. Selmer Larson, a well-known sculptor during that time. I love the hull design and am interested in working with aircraft plywood. 

 

 

I am really interested in seeing how well I can do using the tools I already own – I don't want to buy a lot of stuff just for this model. Here's the strongback (materials from Home Depot) and the beginning of the keel. It's in two halves to make it easier to form. I don't own a table saw so most of my timber will be standard dimensional spruce. 

 

 

Here are the molds, and my first pass at the keel fin. Parts of the fin will extend up to the deck to support the mast. Molds are made of MDF and the fin is two layers of 1/16" aircraft plywood epoxied together; to be built up and strengthened later on. I do admit, I bought a nice jigsaw just for this model; even so the molds do not feel very accurate. I can fair up the hull later as I get more into it (I hope).

 

 

Sheer clamps are now on the molds. If I accomplish nothing else, I am proud of the joint!  The hull is double ended so the bow is easy ... but then the stern has to be just right as there's no going back at that point.

 

 

Here's the framework with the sheer clamps installed. It all feels a bit wobbly so I put some dowels between the molds to add some rigidity. If you look carefully you can see my high-tech twisted wire clamps. The green tape will help keep the boat itself from being glued to the molds. At least that is the plan. I"m not sure how I will get the  boat out once it is planked either. 

 

 

That's all for now! My main takeaway so far: A huge amount of thought and planning is required for each step. Once the planning is done the actual "work" takes very little time at all. I was surprised how far you have to think ahead to make sure everything will work out at the end. I'm guessing this is an experience most of you all are very familiar with. 

 

Thank you all for your attention and I hope to post more soon.

[ccoyle]

I assume that most of our members already realize this, but it's worth mentioning that the build is 1:1 because it's not a scale model -- it's a full-size replica of a craft that was designed from the get-go as a pond yacht. Should be interesting -- good luck!

[Michael_A]

Exactly! There are a lot of forces on a sailing model so the hull and rig have to be very strong. The bow will have a "bumper" to reduce damage in the case of a collision. 

[Ian_Grant]

Class M models are fun to sail. I encourage you to consider RC-ing her. Just need a single winch to control the two sheets and a rudder servo....

[Michael_A]

Ian, Thanks for the encouragement. I've pretty much made up my mind to complete this with RC. I may try to find someone to help me to the RC setup when I reach that point. 

[Michael_A]

Hello all,

 

Now that I have the molds in place I decided to use a block for the stem and transom. It weighs a little extra but gives me plenty of gluing surface, and I don't think the weight will make a big difference. Fun to get all the angles squared away! I am using the second power tool I purchased for this project; a 12" disc sander from Harbor Freight. It works great.

 

 

 

 

I glued the keelson over the molds and attached it to the sheer clamp using the blocks at both the stem and stern. Twisted wire worked well for the clamps.

 

Here's a view of everything so far, including the chine logs which I bevelled in advance.

 

 

Note, the spruce keelson was too thick (too stiff) so I had to cut into it every few inches to make it more flexible. 

 

 

Starting to look more like a boat now! I have glued the keel fin into the keelson to make it one solid structure. I will reinforce the keel later as it has to hold a 10lb lead bulb.

 

 

Thanks for reading and I will post more progress soon. I hope you all had a great weekend!

Edited June 1, 2021 by Michael_A
clarity

[Michael_A]

Time to put on the two side planks! These are made from 1/16" 3ply birch plywood, from Boulter Plywood in  Boston. It's an amazing material – stiff and very light – and the surface is very clean. Here's my first try at wrapping the ply around the hull: 

 

 

I epoxied the side onto the framework, holding it on with as many clamps as I own. I guess you can never have too many clamps! 

 

 

I pinned the planks to the chine using toothpicks to prevent any shifting as the glue dried. The epoxy has no holding power when it is wet ....

 

 

Finally, I made a tiny transom to cover the blocks at the stern (and bow). Eventually the bow will have a rounded "bumper" in case there are any collisions.

 

 

Next step is to put on the bottom. Back to you all soon!

[Jim Lad]

That looks a very nice project, Michael.

 

John

[Chuck L]

Michael

What a great project and it looks like this will be a very well built boat.  You are within 30 miles of 3 AMYA clubs who I'm sure could help you with fitting the RC equipment. Although I don't think they race vintage Marbleheads. You are also only 60 miles from Marblehead, MA where this class originated and they still race vintage Marbleheads like the one you are building. I picked up a 1970's Marblehead late this past summer that I can't wait to start racing in April. I will be attending the Wooden Boat School in June to take a pond yacht restoration class and have found a vintage Marblehead hull/keel that was damaged in a flood. So I'll need frames in the interior, a deck, radio equipment and all rigging to build during the week in ME.

 

You might also consider joining the US Vintage Model Yacht Group (USVMYG.org) which is the group who enjoys building, restoring and racing model yacht designs from before 1970. The vintage Marblehead is one of the largest classes.  There are all kinds of resources available on the USVMYG web page including locating and installing radios.  Last October we hosted the US Vintage Nationals outside of Philadelphia. Here is a link to the video of the Marblehead class races.  I was racing number 150 and came in 12 out of about 20 boats which was fine since I just started racing this past summer. "Pirate" the orange number 150 was a loaner from the commodore of our club since I did not have a Marblehead yet.

 

Please also post your build pictures on the USVMYG Facebook Page or send them to me, I'll make videos of them and post them to the YouTube channel if you want.

 

I can't wait to see your progress.

Chuck

 

[Roger Pellett]

A recent WoodenBoat magazine article had a recent feature article about a present day reimagined model yacht class that is popular in the Pacific Northwest.  Interesting stuff.