MM21

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Jmk2000
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MM21

Post by Jmk2000 »

Hey y’all, relatively new to wooden boat building as I’ve only gotten started with building a little hybrid duck boat so far but the boat building itch has taken hold. I’m really intrigued by the MM21. I have always loved the tug lines and a proud bow. Has anyone ever built one of these with a small diesel inboard, say 10hp?

TomW1
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Re: MM21

Post by TomW1 »

Not with a diesel engine. Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

Cowbro
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Re: MM21

Post by Cowbro »

While I don't have that same boat. I do have an HMD19. Which is similar. I wouldn't waste my time with a small diesel for these boats. I have a 2021 suzuki 9.9 efi with power trim and tilt. It was $3000 with controls. It gets ~12nmpg at 5 knots. It is essentially silent, so much so that I was flushing the motor at home one day and forgot about it for an hour. Lol.

I don't have to worry about inboard running gear, stuffing box, cutlass bearings, propeller hanging down under the boat, etc.

A small diesel is going to open up a whole bunch of extra costs and complications. And no doubt be noisier than the little Suzuki.

If anything, these would be the perfect boats for electric power. My HMD would easily handle enough battery for a full day of fishing. However the cost over the suzuki would be about double depending on how you set it up.


Phil

Jmk2000
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Re: MM21

Post by Jmk2000 »

Thanks for the input. It was just a question. I saw the MM21 and fell in love with the lines and no need for a big engine. I’m a retired Coastie and have worked on diesels and outboards for years. I don’t know the HMD19, I’ll have to look at that one. I did purchase plans this weekend for the MM21 and my wife and I are talking about building it together starting in a year or two. With the thought of doing the Great Loop in a boat we built together. Who knows what the future holds but definitely going to be some fun and adventure. I’m thinking a 9.9 long shaft Yamaha or Suzuki would fit the bill nicely. Just gotta plan for a larger fuel tank. Plans call for a 3 gallon.

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Re: MM21

Post by blueflood »

Hi Jmk2000

I did not consider the MM21 but as for the HMD19, I did lean towards going full electric very early on before actual construction but decided to go with a 9.9 four stroke instead. In retrospect and now much later (and with likely advances WRT batteries) this is the route I would take should I build another HMD19. The main reason is weight distribution where the HMD rides bow high; way more weight forward, less noise and generally less hassles with gas plumbing.

Torqueedo has a few options which would be ideal. There must be other companies as well and although initial cost may be prohibitive as per Cowbro, for me it would still be better.

And...building the HMD19 would have been perfect for a couple's project. It is a big boat and took 8 years part time. Many times I have mentioned to my wife how fun it would have been (we were not married or even dating back then). Then again, you can't have two "bosses" :lol: At least we enjoy cruising together and we make a great team in this respect.

Regards,
Marc

Jmk2000
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Re: MM21

Post by Jmk2000 »

Hi Marc,

I just went through your HMD19 build forum this morning trying to figure out what one was. Dang she’s a pretty boat. I hadn’t even thought about electric but have now set my heart on a 9.9 for the boat. I saw you built in a fuel cell. How big did you go? I noticed on the plans for the MM21 that it does call for 150-200 lbs of ballast in the bow. Do you know what people typically use? Would pouring concrete in since it would fill in to the shape of the hull work? Any suggestions would be appreciated.

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Re: MM21

Post by rick berrey »

No concrete in the bow . If your going to go on longer trips make the ballast removable and use the space for storage . You can shift weight forward on a long trip .

blueflood
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Re: MM21

Post by blueflood »

Hi Jmk2000,

The tank is 12 gals, I forget the max range tho but around 250(?) miles at low RPM rings a bell. It is aluminum built by Atlantic Welding, this is where quite a few builders had their tanks built. BTW, I have not used it yet - only two 3 gal portables for all day cruise but plan on using it this year. It needs to be filled and checked for any hose leaks - that was my reason and why I was debating on full electric.

Mind you, there is nothing like the smell of a gasoline fueled outboard and it is relatively quiet.

As for ballast, I bought ballast bags filled with sand for 60 lbs. This year I bought three rectangular dumb-bells of 25 lbs ea and will put those ahead of the head. They are 1" thick by 7"x19". Also, I always carry one or two 5 gal jugs of water and a few bottled water cases. It really needs a lot of weight up front on top of what's in the locker. And she rides like a champ when loaded :D with a comfy and safe feel in any weather we get.

Marc

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Re: MM21

Post by OrangeQuest »

Jmk2000 wrote: Mon Jan 16, 2023 2:29 pm I noticed on the plans for the MM21 that it does call for 150-200 lbs of ballast in the bow. Do you know what people typically use? Would pouring concrete in since it would fill in to the shape of the hull work? Any suggestions would be appreciated.
You could always just use a ballast tank for water. Could be fresh water you fill up before launching and have plenty of water for washing up with. 20 to 25 gallons would be the 150 to 200 pounds it calls for. Will come in handy for long adventures with the Mrs. Since it shows to have a small galley, it could be an aux water storage that is only, meaning the water is used for the weight till needed, used for long trips and no fresh water supplies in route., or far apart. Then if get in rough seas and want to bring the bow up can dump that ballast. Just a thought.

Would love to follow a mini-Maia as she is being built.
"that it isn't just an ordinary sort of boat. Sometimes it's a Boat, and sometimes it's more of an Accident. It all depends." "Depends on what?" "On whether I'm on the top of it or underneath it."
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Jmk2000
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Re: MM21

Post by Jmk2000 »

Orange quest,

That’s not a bad idea. I would like to have a good sized water tank for sure with thinking of the great loop. Plans call for a 13 gal FW tank but if I can get bigger I certainly will. I’m hoping for 20-25 gal FW and fuel tank. Once I start the build I’ll have a better idea of what’s possible. I will definitely document the build when the time comes for sure. I’ve been pouring over the internet with not much luck of any finished MM21’s. In the plans it calls for the 13 gal tank under the berth so maybe that’s what was intended.

Josh

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