Glen-L.com

Hi all:

I have the DE 23 study plans and I would like to make one change.

Is it possible to move the inboard engine position back (towards stern) by about 1 foot from where it is on the study plan picture ?

The reason being I would like to extend the cabin back about 1 foot

Many thanks for any help

JB

_________________
JB - Chicago, IL

Boats Built:
8 foot pram dinghy (2008)
16 foot center console (2009)
23 Double Eagle (2013)

JB,

You can move the motor back, but you'll be increasing the shaft angle which would decrease efficiency. It would be better if you extend the cabin and work around the motor.

_________________
Gayle Brantuk
Vice President
Glen-L Marine
Visit our Blog & Create Your Own!

I got a Double Eagle hull inboard powered. Tell me more about your engine & transmission and maybe I can help you get there.
Have you finished the hull yet?

_________________
God Bless our Troops; especially our Snipers

Gayle/Ken...Thanks for your help....

Gayle...if I stretch the cockpit aft by 1 ft (length of DE23 would be 24) could I just move engine back and keep the same shaft angle etc keeping efficiency the same ? I could then extend cabin back 1 foot and still have the same cockpit foot print as in the study plan, but the engine postion 1 ft aft ? Not sure if this would work but would be great if I can do this

Ken....I haven't started build yet but trying to make my next boat build decision - which is down to 2 boats, the Double Eagle 23 streched to 24 feet or another plan by another company. I have previously built an 8 foot tender and 16 ft center console Dory. Right now the Double Eagle 23 would be the winner if the engine could go aft 1ft from where it is on study plan - and length of cockpit increased 1 foot aft.

Any other thoughst would be very helpful ? thansk...JB

_________________
JB - Chicago, IL

Boats Built:
8 foot pram dinghy (2008)
16 foot center console (2009)
23 Double Eagle (2013)

How about stretch the whole boat 10 % by re-spacing the frames aft of the stem ? (advised rather than just one area)

That would probably give you the room you need and not change the shaft angle or balance or hull shape/dynamics.

_________________
Boat building can best be defined as an endless series of
tragedies obscured by the occasional miracle, followed by a good bottle of beer.

Don't Dream Your Life, Live Your Dream

JB--yes, UPS Pirate is correct. We don't recommend that you stretch an area of the boat, but rather the entire hull. See our article for details: http://glen-l.com/designs/hankinson/changingplans.html

_________________
Gayle Brantuk
Vice President
Glen-L Marine
Visit our Blog & Create Your Own!

JB; By stretching the plan the 1 1/2 foot from 20 ft t0 21.5 ft on my Titan, and using a motor that has a shorter length than that on the plan, I gained a foot in the cabin, and also another foot at least in the forward section, giving me enough room for a full size head with hanging locker opposite.(aft of the v berth)
I also kept the same ( 10%) shaft angle... well within guidelines. I did however gain some setback by going to an 18" prop as compared to the 22" shown on the plans. Turns out talking to a builder of this plan that the 22 is too much prop and they settled on the 18 as perfect. This is also the recommended prop by Michigan Wheel. This allowed me to shift the engine up and backquite a bit.
By the way, stretching introduces some problems for scaling anything off the plans

Doug

Are planning to build the full deadwood skeg? I didnt on mine. I did stretch mine 10% per the plans.

_________________
God Bless our Troops; especially our Snipers

Thank you all for your helpful comments.....

Based on upspirate and slugs comments I guess I would do the following:

1. I want to stretch the boat 1.5 feet to total of 24.5 ft ( I only have a 26 ft long garage to work in so its tight)
2. 23-24.5 ft = 6% increase in overall length ?
3. Move each frame station 6% further back to stern from stem e.g. if one is located 22" now from the front of stem - its new location would be 23.3" etc. and so on to all the stations

Just doing some calculations on the DE23 study plan it looks like I would gain only about 6.5" extra length in the cabin.

Am I doing something wrong ?

Many thanks for your advice...JB

_________________
JB - Chicago, IL

Boats Built:
8 foot pram dinghy (2008)
16 foot center console (2009)
23 Double Eagle (2013)

If you stretch 10% you get a boat 24'8". At least mine is. You only stretch from frame 6 and aft. Frame 7 lies directly on the stem so it doesnt get the stretch. The cabin bulkhead is on frame5 so that much would not see much stretch at all. You would have to move the cabin bulkhead aft to where you want it to get a full foot more cabin.
To get the engine further aft you can do all of the following and I think you can do it:
1. use the shortest engine/tranny combo you can find. (4.3L V-6 with ZF45a down-angle tranny)
2. use moderate prop diameter with moderate tip clearance. I suggest 14" 4blade or, 15" 3blade.
3. use moderate gearing to suit above prop. 1.5:1 will do
4. cheat a little bit and move rudder port aft a inch or so
5. build 10% stretch into the hull
All of these things laid out together should allow the engine/driveline to give you a foot.
Put in a false frame at station 41/2 for the cabin bulkhead for the cabin stretch

_________________
God Bless our Troops; especially our Snipers

JB; Kens is right on. Also, since you're also stretching 10% forward of the cabin, ) probably another 6" but I'm not sure without the study plans on hand ) you can steal some cabin length out of here also.

Go for it
Doug

Kens and Slug:

Thanks for your help.

Kens...I'm still a confused and sorry for my stupidity but shouldn't I start the stretch aft at frame 5, the cabin bulkhead, and then stretch 4, 3, 2, and 1 to get the extra length ?

If I start at 6 wouldn't I just be moving the whole space between frame 6 and 5 aft and not gaining extra length there ?

I just can't picture it in my head ??

Thanks for your patience...JB

_________________
JB - Chicago, IL

Boats Built:
8 foot pram dinghy (2008)
16 foot center console (2009)
23 Double Eagle (2013)

I know you want the space at a certain area of the boat,but the idea is to spread the stretch over the whole boat(well,aft of the stem) so the lines stay fair.

If you just stretch say the aft area,the lines run a certain way up to that area,then change at that area.

Draw out a shape say a football shape,with certain cross dimensions,(frames) then draw a stretched shape with those same cross dimensions with equal spacing and see the final shape.

Now draw with the stretch in just one area, and you will see that the lines don't flow right

_________________
Boat building can best be defined as an endless series of
tragedies obscured by the occasional miracle, followed by a good bottle of beer.

Don't Dream Your Life, Live Your Dream

When you stretch one of these designs such as Dbl Eagle, you do not alter the stem you only stretch aft of the stem. Notice on Dbl Eagle that frame 6 & 7 land on the stem.
The stretch would start at frame 6 and stretch going aft in each station the same percentage all the way back to transom. On this build the stretch is frame 6 to transom.
Now the cabin as drawn is frame 5 going forward therefore the cabin would only see about a 3" stretch. that is why I said to install a false frame about station 4 1/2 to allow your 1 foot wanted stretch in the cabin. you would now put cabin blkhd at sta. 4 1/2.
UPSpirate is correct in his post, you cannot stretch just in one area, you have to equally space the stretch the length of the hull for it to look correct.

_________________
God Bless our Troops; especially our Snipers

Re; "my fishing boat goes Chicky" and "extending the cabin" reminds me of so many years around the fishing industry in Puget Sound and Alaska.
I just had to throw my $0.13 in here.

Lots of our old wood boats had the engine amidships. All of them as I recall.
They put the cabins on top, along the sides, forward, aft and left em' on the beach.

All of those Cabin decisions had to do with Noise, Heat, access, Convenience etc.
Lots of them had the aft cabin wall about the middle of the engine with a door on one side or the other. Table on top the Engine. Toasty warm in those cabins.
Most had the Aft Cabin bulkhead removable. The Door and post were removable too.
Dry Exhausts often ran up the Aft Cabin wall on the outside. Ladders, Hydraulic pumps etc. All kinds of stuff hung on those Aft Cabin walls as time went by.

Among the problems we faced with those old wood boats was the loosening of the fasteners and the wood just plain giving up around the fasteners. Not specifically "nail Sick" but the wood can only stand so much stress and it begins to decay.

On those old boats, with speeds that would barely make 7-10 Kts, you know it wasn't jumping waves that took them apart.
It was too much of a load on various parts. That came from the Fisherman adding Cabin etc to the original design.

If you plan on keeping this boat a long time, keep the original design or stay within the original design limits.
Remember this is old Grey-Beard speaking to you from the Wood boat graveyards of Puget sound Washington.
Relating a lot of hidden reasons to stick with the engineers opinions!