Skagit 20 - Alaskan Bulkhead

[Helmar]

I am really interested in how she is going to handle. I think she will take that modification and do just fine with it.
My 59 Skagit seems to be a little heavy in the butt as she has a cast iron Volvo B18 and one of the first Heavy Volvo Penta outdrives on it.
Fuel tanks are up by the cabin bulkhead.
When I got her she had some kind of early worm drive trim tabs on her that were not working.
Getting them to work Really changed how fast she comes up on plane.

With the extension also being a floatation device should help and I am really interested to hear how she does.

The ones I was not to sure about were the ones that had the stainless piping off the transom and the motor hanging out a extra 2 feet off the back. To me its like holding a gallon jug. Hold it with your arm extended and the weight shift was very noticeable.

You have solved that problem.
Some place I remember people saying that those hulls were only designed for a couple of maybe 35 OMC's on the back.
Some of the people that over powered (100 and 115hp) made them scary and porpoising. Like a barn door with a motor on the back.
Others that put all the weight on the rear, batteries, fuel, gear and then pour weight in the bow always made me wonder why? To me, it just meant the performance and fuel economy was compromised..

I had the rare opportunity to work at a shop that was rented from George Calkins. Calkins Craft and of course the famous Bartender boats.
I would listen to him anytime he was willing to share his engineering of his boats. Pretty smart cookie.

[Skagit Hideaway]

Tim and Bruce,

Thanks very much for the feedback. Much appreciated.

Not sure what the Skagit 20 hard top weighs. The one that came on this boat (not original) was heavy - ca. 40lbs maybe. It was 3/8"+ thick in places. I liked the shape enough to keep it, so I added 24" to it's length and am in the process of thinning it (grinding) as much as possible and will add some Skagit-type ribs where support is needed. The cabin is 6 laminated, 2-1/2" wide x 1/2" thick plywood posts ("L" angle on the front and rear corners, "T" in the middle) with 1/4" thick plywood (laminated) walls on the sides and 1/2" on the front, to hold the windows. All the post corners/edges are beveled back to make them as light as possible. I'll just have to see how light I can make the roof and rear wall/door.

The keel modification was just "talk" at this point. We'll finish the boat with the original hull + extension (with tapered (reducing) keel and air-o-glide grooves), and see how it handles - strapped in with test helmet/crash cage/head-neck support/wet suit perhaps.

The 75hp E-tecs are a possiblility, but they are essentially the same motor (weigh the same - 310lbs) as the 90's. The 60's are the next smaller motor at ca. 250lbs, but there is the question if one would get the lengthened boat up on plane, with a little power left to deal with rough seas, or not. We could still go with a larger single and kicker as well. Have to see when we get there.

[bruceb]

Lance-
I concur with Tim's assessment of all the weight and materials considerations. By installing the extension, you've improved the planing characteristics and the efficiency of the hull. As well as the cornering with the air glide bottom. The lower center of gravity helps counter the lower hull weight relative to the cabin structure. Kudos in the weight reduction of wood structure and use of lexan in side windows.
Also, the concerns of how the hull rides (nose high or low "bow steering") brings up the difference in your power train configuration. A modern outboard tilt trim feature can compensate, to a point, compared to a fixed inboard. Tim's example of added strakes might not be required in your final hull "tuning".
I can say in communicating with a Skagit 20 owner with a 90 Etec ( Scott McDade) and a 17 Skagit owner as well, that a standard 90 is more than adequate for a "stock config" boat. By putting 2 90's on your hull, it would more than compensate for your added ship's weight. Clearly your intention of having the redundancy of twins is a winner for the mission (s) the boat is intended. If you were to want a "money saving" exercise, twin 75s would still be impressive, and adequate planing for a single engine function, should one become disabled.
Chuck Carey's 17 Skagit Express restoration "Kalakala" with a 2011 90 etec.
The project's coming right along, very impressive ! Keep us up w/ pics !!!

[McSkagit Tim Jones]

Okay, what do you think the hardtop weighs? I thing the added waterline length should make the boat come on plane easier and overall make the whole rig more efficient. There was also talk of a keel modification. This gets a bit trickier. On the Skagit 31 the keel is about three inches wide and gets deeper as you go aft. Above about 25 knots, the keel acts like a water ski and begins lifting the hull. Also the turn of the bilge, where the hull meets the keel has a very big radius. This also adds lift, but also makes for a very soft ride in the 15 knots and above range.

There are plenty of planing hull boats out there with handling issues. Some I'd consider dangerous above about 20 knots. There was a story written in Professional Boatbuilder some years back titled: Handling Issues in Planing Hulls (or something like that). It's common in many production hulls.

A friend of mine restored an 18 foot Reinell. Wood boat, originally a utilitarian skiff you might find at a fishing resort in the 1950s. He put a lot of work into it, sheathed the hull with CVG cedar, added a deck and windshield (frame of walnut). I found a 220 HP BMW I/O for him which he installed and decked over the engine compartment. Nice interior cushions.......put quite a bit of money into the boat.

On first test cruise he discovered the boat had a serious handling flaw. Above 20 knots, the bow would hit a wave and the boat would suddenly veer to starboard and the bow would dive. If you were standing, you'd be ejected from the boat. The guy was bummed, to say the least.

I suggested he add two strakes to each side of the bottom and extend them about 2/3 of the hull length. A tricky piece of wood working as the dead rise varied going aft. Long story, short, the strakes broke the hydraulic suction on the bow and problems solved. Boat could do 42 MPH with the 220 Beamer.

My two cents worth.......

Cheers,

Tim

[Skagit Hideaway]

Tim,

Thanks for the info and encouragement.

From the brochure, the '56 20' curiser at 1025 lbs appears to be 25lbs lighter than the '55, somewhat heavier than the '58, 75lbs - 100lbs lighter than the 59, and ca. 300lbs lighter than the '60 and '61 models. I'm not sure where the differences lie, but according to that, the '56 is lighter than most of the 20 footers I've seen............in pictures. Ha. ha. This is my first.

I was figuring on lexan for the side windows, thanks. I got carried away cutting the window openings, initially. They are going to be a good deal smaller (vertically), so a lot less glass in the front. The new cabin/roof are trimmed of all excess weight wherever possible, so I don't think they will add that much more than the 300lb heavier '60/'61 hardtop models, if any. I'll know more after I weigh the thing.

The ca. 24" extension weighs ca. 150lbs - 175lbs, but adds ca. + 60lbs of floatation for each inch it is submerged. I plan on doing a semi-accurate hull measurment/weight analysis so I can figure where to put everything, down to the extra fish hooks. There is only going to be 2 in the boat most of the time. The extra length should make the boat steer straighter, handle better in turns, and handle chop a bit better, all of which mean better milage, to compensate the extra surface in the water - theoretically. We'll see.

......I've never owned a stock anything....

Lance

[McSkagit Tim Jones]

I finally got a chance to read through most of this thread. Ambitious for sure. Nice designs and workmanship. The key issue in my opinion and experience is weight. Weight is always an issue in small planing hull boats.

My Skagit 31 Saratogan became overweight when I added diesel engines, picking up almost 1000 pounds from the engines alone. Then I added more fuel capacity, the electric drive system and battery bank to power them, another 900 pounds. Well the boat carries it all pretty well, but some of the useful payload (people and gear) has been used up with battery weight and fuel. Looking at the original design, designer Howard Roberts was spot on with his weight calculations for engine placement, weight, etc.

Need to be careful modifying these older boats. The 56 Skagit 20 was (is) already heavy; heavier than the later models. The glass weight alone for the superstructure (what you call the Alaskan Bulkhead) is going to be considerable. Maybe Lexan for the side windows.....much lighter.

Look forward to seeing this boat out on the waterways. Twin 90's more than enough power, especially with the hull extension....

Cheers,
Tim aka McSkagit

[Kelly]

I gotta say, every time I open this thread it always amazes me...nice work on the addition.

[Skagit Hideaway]

Sweet Music.

http://www.youtube.com/watch?v=moK_3cC32AA

http://www.youtube.com/watch?v=473d_rntSKY

http://www.youtube.com/watch?v=3yquifWWK7A

[Helmar]

That is getting a good glassing for sure.
It will be nice to see more of it when its in primer...Good job !!

[Frederic Lynes]

Looks great! A pair of Evinrude V8 300s would look great on there!

[Skagit Hideaway]

More sanding, glassing, fairing to do on this side...

[Skagit Hideaway]

Port, outside top piece almost ready to clamp/glue in. The outside ledge is still a little high - thus the gap at the corner curve. Edited out some distraction in the background.

[Skagit Hideaway]

Helmar,

I contact cemented a plastic sheet over the Port aft corner of the boat and then laminated over that. The cured laminate pulls right off the plastic - original Skagit 20 stern corner radius The contact cement comes off without too much trouble. See post #38. I hope everything is on right, cause it isn't coming off, ever. Modern, low viscosity resins really soak into the old laminate surfaces.

Lance

[Helmar]

That is interesting for sure.
How did you make that radius on the corner ?

[Skagit Hideaway]

Thanks Lyle,

I think it is going to actually work.

Lance