The feasibility of modifying a Twister

[RFNK]

Apparently Kim Holman believed the Twister, built to maximise performance under the prevailing racing rules of the day, would have been a better boat if he'd added two feet to the length. I gather (probably mistakenly!) that by this he simply meant dragging the lines out aft by another two feet, with a slightly smaller transom. It would need a new rudder configuration too. I'll commence restoration of a Twister soon, involving replacement of quite a bit of planking (mahogany, grrrr) and the transom (also mahogany), and some frames. Would anyone know if it would in fact be feasible to modify an existing Twister to the lines Holman proposed for an improved boat?

This will, of course, remain an intellectual exercise unless, by chance, there is good information suggesting it to be a wise move. The last thing I intend to do is butcher such a nice boat (apart from the usual stuff-ups of course!!).

Here's a picture of the Twister (rudder removed - apparently it fell off; it's a transom-mounted arrangement, similar to a Folkboat):

http://i470.photobucket.com/albums/rr69/rfnk/Windrose2.jpg

Rick

[PeterSibley]

Rick ,I very much doubt that any extented version would be as simple as that .Probably an increased station spacing would have been the best / easiest way to do it ?

[maxwaterline]

Rick, I have seen a couple of local boats, with the deck removed, that have been extended at some stage in their life.

The original transom was left in place and the transom hung rudder seems to be replaced with a rudder and shaft, like in a typical inboard rudder installation but in the same location as the original rudder.

One boat was a Seabird ( I think they added another plank to the topsides as well) and the other was a heavy displacement cutter, 40's I think.

Both boats have been well done but there is a sense that something is not quite right, differences in sailing unknown, and the space created doesn't seem to be particularly useful, partly due to the increased level of structure needed.

Cheers Adrian

[RFNK]

These comments are probably right but apparently it was Holman himself who said that he'd have liked to extend the length. The Twister does have that `there's a bit missing at the back' look to it so I'm keen to find out what Holman actually meant. I am sure he was talking about the advantage of increasing waterline length but that's about all I know.

I'm a bit doubtful about the increased station spacings. The Twister is not heavily built. Frames are light, planking is not thick. They were built for racing so an inrease in station spacing would have implied an overall heavier build, I think. I have the impression that the extension Holman was talking about was less involved than that.

Rick

[RFNK]

I know there are a few Holman and Twister fans out there. No comment from any of you? If you think this is just a dumb idea, no problem - I suspect the same, but I'd be interested to hear from anyone with a bit more knowledge of Holman's ideas on this issue. Rick

[Jeremy Burnett]

You could try his North Sea 24, which is 31ft on deck and looks like a bigger Twister.It subsequently became the Rustler 31 in Glassfibre. Currently still in production is the Rustler 36, again with the transom stern.

[RFNK]

Thanks Jeremy. The information about the Rustler was very helpful. The Rustler just looks like a bigger Twister and I guess it's probably what Holman had in mind when he referred to the advantages of a bigger Twister. I'd wondered whether he'd meant creating more of an overhang aft, simply to increase LWL rather than a wholly bigger boat but I'm guessing that this wasn't the case. Rick

[Andrew Craig-Bennett]

Amplifying Jeremy's point, I think Kim Holman liked counter sterns but the combination of the RORC Rule and the cost of building meant that many of his boats had transoms. I think that is what he meant.

There is a counter sterned version of the Twister about - just the one boat, I think, but the counter sterned version of the North Sea 24 is the Shaker (Kim's own boat plus one sister) and the GRP version of that boat (i.e. a Rustler 31 with a counter) is the Northney 34.

You will notice that the counter adds three feet on a 24ft waterline so I suspect that a counter on a Twister would add two feet or so on a 21ft waterline.

These waterline lengths determined what races a boat could enter for at the time when Kim Holman was designing them.

[RFNK]

Thanks Andrew. I thought (hoped) you would join this discussion. Wasn't it you that declared the Shaker a really beautiful boat? So, the practical question remains: would there be any advantage in adding a counter to a Twister that's about to be substantially reframed?

This can get spooky. I just did a bit more searching and came across a piece that referred to a counter-sterned Twister winning the 1967 Lloyds prize. The name of the boat was Eulali. Now, the reason I have the Twister is through referral from a marine surveyor friend who sailed a Vertue (now rotting away on Pittwater I believe) from England to Australia many years ago. His wife's name is Eulali.

I also came across this post from another forum in 2002:

I can't add much. The Northney 34 is GRP version of the Shaker class, which is the counter sterned version of the North Sea 24. The 31ft original Rustler is the GRP version of the North Sea 24.

The Northney 34 is one of the prettiest GRP boats of all time!

"Shaker" herself is on the East Coast now (saw her the other day) and there are I think one or two more wooden ones, and I believe that there are around 30 Nortney 34's. The reason for the short production run is that the moulds were destroyed in a fire.

That's as much as I can contribute.

Poster's name was Mirelle. Andrew?

Rick

[shamus]

An interesting speculation.
If the station spacings were increased, in a new boat, there would normally be more frames- the existing frame spacing would be at least maintained, and scantlings might even need to be increased. With an existing boat I expect there would be something to be gained by what you suggest, which is to add a couple of feet at the stern, presumably by adding a horn timber to the sternpost and a new smaller transom, adding a tube for a rudder stock etc. The additional planking also has to join the old planking in a suitably staggered manner, which perhaps makes quite a big job of that part of the operation. I bet it could be done, and made to look good too- but then I like that sort of stern termination. True Twister enthusiasts might be horrified.
Edited to add: Was writing this before seeing the last few posts. Really interesting there are examples to refer to. Should make it easier to decide I would think.

[Andrew Craig-Bennett]

Yes, me, Rick.

Unless you have a lot of planking to replace in the stern area, and a really rotten transom, adding the counter would be more trouble than it is worth, I suspect. The Twister does not look "foreshortened" when afloat - when ashore she does owing to the relatively dep draft. I think it is a very handsome design.

[RFNK]

True Twister enthusiasts might be horrified.


That's something that worries me too but if there was originally a counter-sterned version which was esentially just a Twister with a counter and obviously the different rudder setup, and IF it still looks good and there are sailing advantages, then why be horrified?

I'll be arriving home in a week so I'll then be able to look at the Twister drawings that Andrew C-B and Andrew D were so helpful in obtaining from Holman and Pye. I'll do the exercise of extending the lines from those drawings but I'll get into trouble when I have to consider rudder placement and shape, I suspect. That's where, if this idea is feasible, I'll need the help of someone with design expertise. I will already be replacing a lot of planking and the transom so that's less of an issue. Rick

[shamus]

I agree. A quick google finds one advertised at some stage in South Africa as well.

[Hwyl]

This is a serious suggestion. You could carve a counter out of styrofoam, to see how it looks. My guess is that it might be aesthetically better, but not matter much to the sailing qualities, it would add a little to the length and a good bit to the weight. A lot of work for no, or negative returns.

Stick with what you've got.

[Andrew Craig-Bennett]

I'm sure Holman and Pye will have the drawings for Eulali.

[Jeremy Burnett]

Andrew's mention of Eulali jogged my memory, I went on her a few years back when she was for sale on the Hamble. My memory is that she somehow felt smaller than a transom Twister , a bit pinched at the stern.

[Ed Burnett]

I was thinking I remembered a Twister with a counter in one of my father's boat searches - Eulali must be her.

It might be worth bearing in mind that there are very few boats out there that wouldn't be better if they were two feet longer. There are any number of things that might constrain the length of a new design, rating considerations are one, more likely is cost or simply the fact that most people perceive the size of a boat based on her length, and designers and builders will try to make a boat appear as "big" as possible within that length. Ends therefore might come out a little snubbed, or middles a little broad (although I do not mean to attribute either of these characteristics to the Twister).

In an existing boat, I doubt it would really be worth extending the counter unless substantial rebuilding was needed anyway. Either way, the form of the counter and the shape of the eventual transom would be almost entirely dictated by the existing afterbody shape so it is not like you would have much control over the end result. Eulali looked fine to me, but it would be natural for her counter to feel a little pinched unless the original transom was excessively broad.

[RFNK]

These are all really good points and helpful suggestions; thanks! Windrose (the Twister) will need a new transom and I estimate that about 1/2 of the planking above the waterline and aft will need replacing. I don't like the mahogany she's planked with at all - it just seems too soft and prone to rot to me. The alternatives I think I'm faced with are 1. Making good all planking, re-splining and hoping that the remaining planking holds up. 2. Making good all planking, re-splining and then sheathing. 3. Replanking in a more suitable timber (I'd like to use flooded gum (as it's very stable) but I worry a bit about the weight). If I go with the third alternative, then installing a counter becomes a bit more viable but still only worthwhile IF there would be a notable improvement in performance.

Andrew, after the difficulties in contacting the guy at Holman and Pye last time, I don't suppose you'd be willing to see if it is possible to obtain a drawing of Eulali would you :confused:

I'm travelling home to Oz this weekend for a couple of months and will commence at least tapping a few boards here and there on Windrose so I'll probably start a Windrose thread to gather ideas as I go. I have a bit of work to do on Pipsqueak (Folkboat) to try and achieve a deck that's a little less like a skating rink too, bit I hope to do quite a bit of sailing too!! Thanks again for such helpful ideas. Rick

[Andrew Craig-Bennett]

Happy to give it a go, Rick.

I think the performance improvement would be very slight - the Twister is a really good design.

I've never, ever, seen a Twister in need of serious repair work in this country. We have lots of wooden Twisters but they are always well kept up.

[RFNK]

Thanks Andrew, and you're probably right re performance - it just makes me wonder why Holman would have suggested the counter if it made little difference. The state of our Twister is the result of many years of total neglect. A guy with a chronic smoking habit owned it and just left it sitting without any work when he became too ill with emphysema to do any work. He then gave it to a local shipwright who had plans to fix her up but ended up also letting it sit for years while he procrastinated and then eventually gave it to me. I've taken it out of the water, put it in the front yard and built a big shed/cover over it ready for the day when I can commence restoration. The main problem, I think, is the type of mahogany used for planking and the transom, and some cracked frames which I suspect may be fairly typical in the tight turn of the bilge aft. The ply deck and cockpit are wrecked by the combination of badly (ridiculously) applied teak decking and total neglect. I know quite a bit of planking is rotten but I don't know the extent of it yet. I suspect I'll probably replace all suspect planking, re-spline extensively and then sheath with glass, simply because I think the planking is too soft. I'll start a new thread with plenty of pictures soon. Rick

[shamus]

One thing a counter is lovely for is sitting on. I like to sit back there while other folk are doing the sailing. The other thing is, it seems to me a bit like Robb White's description of Rescue Minor. He says there is a little boat underneath and a big boat on top. The little boat gets up to hull speed and leaves its stern wave behind, and the big boat rides on the stern wave. But I must say, from your description above, it sounds as though you have enough to go on with without extending! As a matter of interest and education, what was the fault with the installation of the teak over ply?

[Andrew Craig-Bennett]

So, Rick - you have a kit containing all the metal parts for a Twister, from ballast keel to mast, via the galley stove and winches?

It's a start!

In Britain, Twisters vary considerably in build quality - I have occasional bouts of wanting to go to windward properly resulting in the putative sale of Mirelle and purchase of a Twister - and the years of looking at Twisters and talking to their owners have resulted in a definite pecking order, headed by Tucker Brown, followed by Uphams, then on down... I even looked at the solitary cold moulded Twister (Souters, of course).

The dreaded "African mahogany" has a lot to answer for. However it seems that boats planked with it have done better than I would have expected.

[RFNK]

Andrew, not quite that bad but bad enough to be considering fairly drastic remedial work. I will have to remove the ballast and see how it all looks down there but, otherwise, nothing too daunting really. It really is a lovely boat and annoying that it was left for so long. I'm looking forward to fixing it up. By the way, all the fittings except the galley stove are really good. The winches are particularly nice! I'll post pictures sometime next week once I'm home.

Shamus, this is the second boat I've had with the same problem. The teak decking has been screwed to the ply without any epoxy plug to screw into or anything. As soon as the Sikaflex or whatever begins to come away from the teak, as it inevitably does as the teak dries out and twists a bit, water can enter the ply through the thousands of screw holes that have also opened up by the movement in this thin decking. I like teak decking - it looks good and feels great but I'd only use it if I could find a way to fasten it to the deck without screwing through sheathing and into the ply. I'm not sure what the best way to do this will be but I'll look into it. The only other way to do it with screws would be to use the Gougeon Bros technique of making a little epoxy plug for each screw. A laborious process but one that works - it's what I do for every fastener through or into the deck. Rick