DE 25

[dennisb]

Starting my build thread. The boat is a DE25 stretched to 27.5'. The plan is to do as much of the cutting as I can this winter inside, then move outside for assembly in the spring. I have all the 12mm plywood cut out, starting on the 10 MM. Presently gluing up the stringers.

[fallguy1000]

Cool. I thought the DE25 was the stretched version already. Shows what I know.

[Cowbro]

DennisB,

It looks like you are off to a good start. Are you scaling up 10% in all directions or just stretching the back? Do you plan on a bracket for the OB?

I love the big boats and look forward to following along.

[dennisb]

Thanks Cowbro,

I scaled the boat up 10% in all directions.

My plan is to mount the motor on the transom, no bracket.

Dennis

[TomW1]

Your off to a good start Dennis can't wait for spring to see it come together. Tom

[BarraMan]

Thanks Cowbro,
I scaled the boat up 10% in all directions.
My plan is to mount the motor on the transom, no bracket.
Dennis

That is going to be a BIG boat - I hope you are prepared for the reality check that is coming!

Its easy to say, "I'm going to scale it up 10%"!
Its also relatively easy to do - especially if you have metric plans!
Then once its all done comes the realisation that you have built a BIG boat!

How do I know?

[Matt Gent]

Build threads go here:

viewforum.php?f=12

[dennisb]

I have several questions concerning the DE25

1. I am stretching my DE 25 by 10%. What will the PPI be at the new dimensions?
2. Also, looking to establish the water line. How far below the sole will it be, and at what weight? it looks like unstretched it's ~ 2 to 3".

Thanks

Dennis

[rick berrey]

If you go to Finished boats and scroll down you will see the DE29 , the builder might be a good source to answer some of you questions .

[fallguy1000]

I have several questions concerning the DE25

1. I am stretching my DE 25 by 10%. What will the PPI be at the new dimensions?
2. Also, looking to establish the water line. How far below the sole will it be, and at what weight? it looks like unstretched it's ~ 2 to 3".

Thanks

Dennis

Ppi is a function of wetted surface area(wsa).

Ppi = f(wsa) for de25
Ppi for 110% of wsa will associate.
Be real close to 110% of original ppi.

Edited: wsa increases in two directions, so 121% is correct, not 10%!

Waterline for the same, but larger vessel will change, but the change will be incremental as the new boat is heavier, so the amount of change will be negligible...pf course, if we compare the two, any added weights less than the ppi offset mean she'd float higher.

So, for example, using 600# ppi out of thin air, new ppi is 660#. Then if you add 60# to vessel with larger hull and cabins; you are back at the original waterline.

The challenge in building a bigger boat is not overadding more and more 'stuff' and exceeding the design weight.

And it must not be forgotten a larger boat has more reserve; so ppi increases for each added inch immersion. And the 2nd inch is probably more like 700#.

And this is why I recommended you avoid overbuilding with 1/2" vs 3/8". Because using 6 sheets on the bottom is an extra 66 pounds...

These boats are weight friendly, but only to a point.