Annie and I have been discussing the sailplan, whether the sail should be of medium or high AR, and whether a tabernacle is possible or desirable. There's a lot of personal choice involved here: I don't think I'd want to say that either sail is "better" than the other. 

Hampus Mattsson wrote:Hey Annie!

Yes, I remember the 3 ton(ish) restriction. I put the revised drawings in the illustrations section under the technical forum. You can download them to your computer for easier viewing in full size. The new sketches show the 4 ton version. I don't have time to work on it for a few days and i wanted to get it up there before I get really busy. By the time you have looked at them I'll be available again.

Now, if you like what you see I'll lay it all out in 3D. That includes bringing the displacement back to what it was before, around 3.4 tons, possibly a little less. That will require offsetting the outboard to one side. I'm not a big fan of using two rudders. Although you can argue that two provide redundancy they are still equally unprotected, while a single centered rudder has that nice big skeg in front of it.

I hope you like it better this time.

/Hampus  

First off, the illustrations can't be blown up sufficiently before they lose clarity and  - maybe due to my screen - I find that all-grey graphics a bit hard to interpret.  Could be my failing eyesight, too :-)  Can you do anything about that?

4 tons is too much, I'm afraid.  3.4 is too much, too.  I know I'm asking a lot, but I want to anchor on 8mm chain and a 20 lb Manson Supreme - gear I can easily handle.  And I want that anchor to hold in 55 knots of wind.  Increasing the displacement by over 10% would be pushing my luck, I think.  I can't afford insurance or marinas so security at anchor is essential.

The galley is much more acceptable, although I'd skip the double sinks and I most certainly would not have an icebox/fridge in the corner because I really dislike lifting hatches in the galley counter, but that's easily sorted.  The saloon looks very comfortable.  Is the heater next to the galley now?  Should be a good place for it.  I think I would prefer a double bunk that didn't go right across, fitting lockers down either side, instead.  But how can you get all this in three tons?

I'm afraid I can hardly see the profile plan, let alone read any of its details: it simply becomes a mass of grey when I blow it up.  So what is the draught?  60 cm is the maximum if you recall.  I can't see where the boards go.  As to the rudders, David has contrived to have two rudders each with a skeg in front of them and seems to feel they should work, so maybe that is an option.  The rig now looks a long way aft: is that just an optical illusion?

A very nice-looking little boat, however, with lots of promise.

David Tyler wrote:

BTW, the second boat to be built to the Sib-Lim design, the first sister-ship, just has to be called Sib-ling. Doesn't she?

Annie Hill wrote:

Hampus Mattsson wrote:

I'm almost done working on the revised drawings. It has proven quite difficult. An interesting observation: The outboard well forced the waterline to become longer with 0 rake to the stern post. This added almost a ton to the displacement. An inboard would have added around 200 kilos with tank and all as it would not have affected the LWL.

I have no doubt that you will remember that one of the parameters is: "About 3 ton(ne)s displacement".  And that another is: "Outboard engine".  I have suffered, this season, from the bits that are attached to my engine giving me problems.  I don't want to have to deal with water pumps, compressors or alternators again! But equally to the point, I really don't want a huge and expensive piece of ironmongery in my boat, making access difficult.

The alternatives to lengthening the waterline would be to have a very cramped cockpit, to have the outboard offset to one side of the rudder or to use double rudders.

How cramped is cramped? I don't see that it's an issue having the outboard offset, although I'd prefer it not to be on the stern.  David Tyler has gone for the twin rudder solution, which looks like it should work well with the minimal draught that I'm insisting on.

The alternative to letting the added waterline length also add to the displacement would be to decrease the draft (which is already very shallow), which would affect ultimate stability in a negative way or to reduce the beam on the waterline which would affect interior space and initial stability in a negative way.

This is why there is such a difference between 'simple' and 'simplistic'.  And also, no doubt, why I've never come across any design that fits my desiderata: it's not easy!  I'm looking forward to seeing what you come up with next.

Yes, I remember the 3 ton(ish) restriction. I put the revised drawings in the illustrations section under the technical forum. You can download them to your computer for easier viewing in full size. The new sketches show the 4 ton version. I don't have time to work on it for a few days and i wanted to get it up there before I get really busy. By the time you have looked at them I'll be available again.

Now, if you like what you see I'll lay it all out in 3D. That includes bringing the displacement back to what it was before, around 3.4 tons, possibly a little less. That will require offsetting the outboard to one side. I'm not a big fan of using two rudders. Although you can argue that two provide redundancy they are still equally unprotected, while a single centered rudder has that nice big skeg in front of it.

I hope you like it better this time.

/Hampus  

Hampus Mattsson wrote:

I'm almost done working on the revised drawings. It has proven quite difficult. An interesting observation: The outboard well forced the waterline to become longer with 0 rake to the stern post. This added almost a ton to the displacement. An inboard would have added around 200 kilos with tank and all as it would not have affected the LWL.

I have no doubt that you will remember that one of the parameters is: "About 3 ton(ne)s displacement".  And that another is: "Outboard engine".  I have suffered, this season, from the bits that are attached to my engine giving me problems.  I don't want to have to deal with water pumps, compressors or alternators again! But equally to the point, I really don't want a huge and expensive piece of ironmongery in my boat, making access difficult.

The alternatives to lengthening the waterline would be to have a very cramped cockpit, to have the outboard offset to one side of the rudder or to use double rudders.

How cramped is cramped? I don't see that it's an issue having the outboard offset, although I'd prefer it not to be on the stern.  David Tyler has gone for the twin rudder solution, which looks like it should work well with the minimal draught that I'm insisting on.

The alternative to letting the added waterline length also add to the displacement would be to decrease the draft (which is already very shallow), which would affect ultimate stability in a negative way or to reduce the beam on the waterline which would affect interior space and initial stability in a negative way.