Designing for ferrocement vs wood or steel

Nope, that's why I'm doing it now

With anything more than 6" of freeboard I'm going to have to use some sort of platform. In this case I was thinking probably something removable that goes over the side. I really don't like the lobster boat or downeaster design, but I'll see if I can find something with a lower stern. Another option would be to use a notched gunwale like the Coast Guard does for their rescue boats.

What would be the advantage of a semi-displacement over a full displacement on something not intended to exceed 10 knots?

Like I said above, it will get moved at most twice a year. I checked with the DOT and permits up to 16' may require lights, but are basically a matter of throwing money at them.

Like I said, that's why I'm going through the process. When it comes time to actually do this I will probably get a set of commercial plans, but I feel that going through the process and understanding the trade-offs is valuable for getting the right design.

 

I'm just throwing ideas at you...maybe you'll like the front half of one designer's boat,and the rear from another's.

Looking at your sketches...how about a V-drive to free up more space under there?
Maybe even fit the guest berth and storage space under there and free up more living space.
Once you're asleep,you don't know if you're sleeping in a pipe berth,trunk of a car,or a 300 sq ft cabin.

What about Skira?

Glen-L?
https://www.boatdesigns.com/Power-Cruisers/departments/11/


I'd assume you'll have some sort of swim platform for the kayaks,it's a royal PITA trying to slide out of a yak straight onto a swim ladder.
I'm strong enough to do it,but most people/women can't....the bottom half ends up wet and the yak usually takes off.

Perhaps Pierre means re: semi displacement,a little turn of speed will help you get to places on your holidays.

I assume you know about our BC tides and currents- with a slow boat you can spend much of your vacation time waiting for that 6 knot tide,with a 15 minute slack, to turn.

These are not rivers>>>
http://www.youtube.com/watch?v=184ftWvQHiE&feature=related

http://www.youtube.com/watch?v=avRkd5BOE94&feature=related

 

Missed the most obvious one..

http://passagemakerlite.com/designs/passagemakerlite-39

 

Hey, I always appreciate more ideas!

I looked at Glen L and they have some nice designs, but nothing that really turned my crank. My first response when I saw Tad's design was "Holy cow, that only 40 feet?"

Yeah, I'll have to do something. I was thinking about it after responding to Pierre's comments and what I should have said is anything with a freeboard over 6 inches. Over that it's really hard to pull off.

Wait, I do that every time! Are you saying that's not how you're supposed to do it?

Oddly enough I've been through there numerous times, and usually slept right through it.

I spent three years working deck on small cruise ships and so one year we went through there once a week all season. They always tried to time it to catch the afternoon slack and since I worked the midnight to noon shift I was almost always racked out. One of the few times I was up for it I saw it try really hard to flip a sailboat, and that made an impression, as did the fact that a 192' cruise ship had to worry about the currents there.

What I wonder is how those log tows that only make 4 knots at the best of times get through.

 

..I have a hydraulic platform. It's submerged,so just paddle up,hit the switch with the paddle..and it lifts the Seadoo/kayak/dinghy out of the water.

The log boom guys take a long time,going slow enough to use the favourable currents.

 

Log tows usually travel at about 1-2 knots plus current for over the bottom speed of 3-4 knots.

The other side of buying big power to fight currents is working with the current to vastly increase your cruising range and speed. Most folks on weekend or holiday schedules never quite get this......On any summer day I can meet a steady stream of boats in Sansum Narrows. I'm running 5-6 knots through the water with 3 knots of current, or 8-9 over the bottom (140-150% of cruising speed...for free!), they are bucking 3 knots and covering 7 over the bottom.......usually they don't even understand back eddies and just thunder down the middle, wondering why I'm going so fast the other way and why I insist on running in the middle of the channel and cutting across their bows (following the fast water).....sometimes they yell and wave their fists......I wave back.....

 

Last time I went through Dodd Narrows, even the fast boats waited for the slack current, as this is a place famous for spectacular roll overs if you screw up, get swept and touch bottom. BERTIE plodded along at her usual 5.7 knots under power through the water, but the GPS said we were doing nine, and this was at predicted slack water.

 

If you want a good powerboat model, check out the scale performance of this Schnell Boot. At 1/35 scale this is pretty impressive as far as controllability and wave making. The real thing was about 115 feet and it would be so cool to work out a 55 foot example, 3 supercharged lightweight modern diesels, the very sophisticated triple proportional rudder steering that greatly reduced heeling in hard turns I believe, all designed 7 decades ago and proven in very hard service in the North Sea in all weathers. http://www.youtube.com/watch?v=0oralJQrHlM

 

Protocol question:

I think I have my design pretty much in hand. I found plans from Chesapeake Marine Design that has nearly everything I want and I was able to make a few tweaks without any structural changes.

Here's the question: Would it be bad form to post the study plans I started with and the modified design I ended up with for comment?

Please advise.

 

Protocol IMHO would be to ask the owners of the study plan and the modified design just what they would be willing to let you post publicly. Its reasonable that their IP be protected, but you should still be able to post something to give people a general idea of your journey.

 

I'm sure the co. would appreciate the free advertising.

Just post a link to the boat in question,instead of posting pix just describe it a little.
ie I'd like to move the galley to the port side,and shorten the dining area to put in more storage etc etc etc

 

Call Karl, he'll clear up your concerns. It would be the appropriate thing to do.

 

Found a video of the real ones under way.

http://www.youtube.com/watch?v=ec4XwB1Jg94&feature=related

http://www.youtube.com/watch?v=4CDMyd_JTVY&feature=related

 

With the kind permission of Karl Stambaugh of Chesapeake Marine Design, llc, here are the original and as modified plans.

http://www.cmdboats.com/index.htm

The first two (C-Trawler 34 2 and 3) are Karl's original design, the latter two (CT-34M) are my as modified plans.

Externally, I added the bulwarks (mostly for appearance) added the masts and booms, and extended the canopy on the fantail to add more space for kayaks.

The interior changes mostly involved moving the stairs in order to have a centerline helm and re-working the forward berth. The boat is designed for plywood over frame construction, but I plan to use the NZ style cold molding process which will free up some more interior space. I'm also toying with the idea of adding a foam layer and then another layer of glass for insulation, though it would also have a positive hull strength impact.

 

Looks great to me...the centreline helm gives more continuous space in the forward stateroom.

I see you plan on ditching the washer/dryer,for short trips you can do without but if you're out longer it's great to have.

Aft cabins are the way to go imo,don't hear other people's washroom runs at 2AM 5' from where you're trying to sleep.

Where is the does the margarita blender go?
This is most important and needs addressing before you get too far.