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Key Largo Carolina Dory Build #5: Keel and Bracket Framing

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Blog entry by ccarrington posted 08-16-2017 02:25 AM 1501 reads 0 times favorited 6 comments Add to Favorites Watch
« Part 4: Plywood and Fiberglass Part 5 of Key Largo Carolina Dory Build series Part 6: mounting bracket, glassing keel, priming »


2×4x10 angled on one and and both corners rounded


5” structural screws


countersinking screw holes set every 12 inches from 6 inches from the front


glued on, screwed in, and heads filled


One coat of fiberglass after base coat of epoxy


just for a size reference


The rough framing of an engine bracket/pod. No idea what i am doing and no plans, just kind of winging it. seems like it will work though.


Next, will skin in plywood and fiberglass just like the boat



6 comments so far

View Bumpy's profile

Bumpy

31 posts in 293 days


#1 posted 08-16-2017 11:28 AM

Offering some un-solicited advice. This design is going to be difficult at best to steer, it will tend to pivot on the short keel you have installed. With the high freeboard, flat bottom, & short keel, you will be miserable if there is much wind. Under power, you will slide when attempting to turn.
This is basically a 26 ft canoe.

I understand the desire and satisfaction of building your own boat, I have built several from 8-22ft.

Good luck, you have a great start.

View ccarrington's profile

ccarrington

12 posts in 98 days


#2 posted 08-16-2017 01:26 PM



Offering some un-solicited advice. This design is going to be difficult at best to steer, it will tend to pivot on the short keel you have installed. With the high freeboard, flat bottom, & short keel, you will be miserable if there is much wind. Under power, you will slide when attempting to turn.
This is basically a 26 ft canoe.

I understand the desire and satisfaction of building your own boat, I have built several from 8-22ft.

Good luck, you have a great start.

- Bumpy

Thank you Bumpy, I am enjoying building it very much. Do you have any tips to help make it more controllable or is it pretty much the design of the boat. I saw people putting 6 foot keels on 20 foot versions so i was hoping 10 foot would be enough. I am looking for any advise I can get.
Thanks,
Chis

View English's profile

English

576 posts in 1289 days


#3 posted 08-18-2017 07:01 PM

Chris,
I built a Spira 20 foot power dory. I built it with no keel. and the boat slid sideways when turning at low speed and was hard to keep on coarse. Jeff Spira recommended the six foot keel I put on mine. It made a huge difference in the performance. It now steers well at all speeds. It will turn on a dime when I am pulling a tub.

I installed a 6’ structural Plastic 2×4 6 ft long on the bottom of mine. Jeff had recommenced a 1×4, but it was to difficult to install being that thin.

A lot of how it will control will depend on how it sits in the water. I added a Cabin and a Pilot house and installed my fuel tank forward of center line. And with only a 70 hp motor in the back the boat sat bow low, So at speeds up to displacement speed the boat was bow down and would not steer. I have seen other Spira boats that are left open and have most of the weight in the back that steer fine with no keel.

SO I only needed the keel for slow speeds. What size motor do you plan to install? Do you plan a cabin and Pilot house?

-- John, Suffolk Virgina

View ccarrington's profile

ccarrington

12 posts in 98 days


#4 posted 08-18-2017 07:59 PM



Chris,
I built a Spira 20 foot power dory. I built it with no keel. and the boat slid sideways when turning at low speed and was hard to keep on coarse. Jeff Spira recommended the six foot keel I put on mine. It made a huge difference in the performance. It now steers well at all speeds. It will turn on a dime when I am pulling a tub.

I installed a 6 structural Plastic 2×4 6 ft long on the bottom of mine. Jeff had recommenced a 1×4, but it was to difficult to install being that thin.

A lot of how it will control will depend on how it sits in the water. I added a Cabin and a Pilot house and installed my fuel tank forward of center line. And with only a 70 hp motor in the back the boat sat bow low, So at speeds up to displacement speed the boat was bow down and would not steer. I have seen other Spira boats that are left open and have most of the weight in the back that steer fine with no keel.

SO I only needed the keel for slow speeds. What size motor do you plan to install? Do you plan a cabin and Pilot house?

- English

That is great to hear. The last comment had me very worried. I am planning on a small pilot house in the very front, no cabbin. Gas tank in the rear. Not sure on engine size. Was thinking about 90hp but not sure. How do you like the 70hp? Does it move it well or would you have gone bigger if you could do it again? Awesome build by the way

View English's profile

English

576 posts in 1289 days


#5 posted 08-18-2017 08:40 PM

Chris,

When I use my boat here is the Norfolk Harbor, the 70 hp is more than enough hp for my wife and myself. The chop in the harbor limits the speed of a flat bottom boat to 15 mph or below. When I take my boat inland to a corp of engineers lake. I wish I had more hp mostly when I put 6 people on board. Put as much motor on as you can afford. If I were do do it over I would install a 115 hp Yamaha.

If I were you I would wait about the keel until you see if you need one. If your boat sits in the water the way it was designed you probably won’t need it. But I don’t think it will cause any control issues. It was not hard to install on the trailer.

You can send an email to Jeff Spira and he can tell you if it would cause any issues.

If you leave it on be sure the aft end doesn’t create any turbulence that could cause bubbles that get into your prop. I made mine full height only rounded at the front and tapered back to 1” at the back and ended it 3 feet from my prop.

If you go to my YouTube channel there is a video about prop mods to improve performance when you get a lot of air under a flat bottom boat.

-- John, Suffolk Virgina

View English's profile

English

576 posts in 1289 days


#6 posted 08-18-2017 08:54 PM

By the way the boats looking good!!

-- John, Suffolk Virgina

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