deadrise angle at each panel on each size
 

Does anyone know the actual deadrise angle at the transom for each size of Seacraft hull built, from the original 21' through the 19' bowrider, 18SF, 20SF, 20 master angler, 21', 23SF and 25 Seafari? Does the 21 have the same deadrise as the 23 or the 20? does the 19 bowrider have the same deadrise as the 20. Are some flatter than others?

the 1979 Brochure shows 16 at transom for 18-20', 20 for 23' and 25.5 for the 25 Seafari. Is that the deepest part of the v, or the average across all three panels?

I've put an angle finder on my 23 and 25. The 23 is 20.5 and the 25 is 25.5. But how do you account for the vertical step when measuring the deadrise?

Are you saying that the total average deadrise is 20.5 on the 23, or is that the first slope up from the keel? I'd like to know what each rise is, if possible. Can your angle finder figure that out? And is the 21 the same deadrise as the 23, or the same as the 20?

These measurements are only for the bottom v on each hull. This does NOT include 2nd or 3rd panels. Bottom V only.

If you lay a straightedge on the bottom panel to the chine you will see that the outside tip of the other 2 panels touches the straight edge. The angle of the middle panel is a few degrees less than the 'hull' deadrise and the outer panel is even flatter. A lot of info is on Carls original patent but the angles are different on different hull designs. I will try to dig up the angles for my 23 but I don't have the others.
On my 23 at the transom I got:
Inner - 20.4 (pretty close to Tim's)
Middle - 13.4
Outer - 9.5
Obviously it gets steeper as you move forward. Not sure how exact they are but you get the general idea...

The deceiving part about the deadrise on the seacraft hull is accounting for that vertical step between the panels.

yeah, I get that part. What was looking for is what is posted below on the 23. I realize the magic is that the tips of each step align from keel to outside edge with vertical steps rather than flat strakes. Particularly interested in the difference between the 20 and 21.

The new or old 21?

Mr. Moesly's original 21 (1960's) was 21, 13, 10 at the transom.

New

Seems to me if you placed a level in your boat's floor made the boat as level as possible then used one of these or a better product you could get the dead rise quite easy at any point on the hull.

https://www.homedepot.com/p/Johnson-...-700/100161689

The newer 21 is supposedly just a shorter 23.

Used a level and protractor to eyeball my '88 18' today after reading this thread.
Looks like 20, 14, and 10, as near as I can tell.

Use Iphone to Measure Step Angle
 

I have used my Iphone 6s both as a level and a protracter. Also used it taped to the AV plate (in the driveway) to determine trim angle versus my trim gage. Just tried the iphone upside down and it still reads. Turn on the compass app and sweep your finger quickly from one side to the other to turn on the level. It will read the angle in two directions, so you my have to play with it to get the desired angle.

That would be the same as the 23 and less than the 20.

I measured this on my 1975 20 foot master angler and redrew in CAD

This is a lines plan I was given to work on in the late '80's

Island Marine Group

THIS...for the newer 21 that went into production in 1998, Tracker...built by Silver King

Joe R.
21 SeaCraft
Susie 2

If you park it on a hill you can just measure both sides, add the two numbers together and then divide by 2.

There ya go Big.....being average and making way too much sense!!! :)