Brown/Marples Seaclipper 24MC

Well for a start it only has one bunk.

Admittedly it is a "Snug Double" --but at 3' 2" wide and 6' 9" long it would be suitable for two tall thin people.

 

Its always good to choose those bunkmates carefully Slender and snug sounds fun to me, I suppose an experienced builder could add a step at bunk height with a cabin rework for those wanting/needing more elbow room. Of course that starts the spiral of weight ,complication and complexity. The tremolino crowd used to go for a tent on deck/net when they wanted more room.....

 

OS7 > I feel that the 24MC bears the fingerprint of John Marples more than that of Jim Brown.

Having spent a bunch of time poring over SeaClipper 28 (which also had input from JB) study plans I can certainly see the pedigree. It could be just the boat for someone who likes to potter around on their own and needs a trailerable. The idea of having a more flexible structure is reminicent of one Mr wharram. For low stressed boats with small rigs it can work ok.

I don't see the cabin of this boat being re-worked much without affecting the folding system. One change I'd make would be to extend the cockpit seats aft so one could lay down there.

What are the hull materials - seems relatively heavy for a smAll boat?

 

One change often leads to others for sure. It would mean a wider folded beam with the pivots moved outboard or a higher cabin profile (yuk). Losing the cockpit footwell could gain a bunk aft but doesn't make as much sense as lengthening the cockpit for a boom tent. it really comes down to what features are you willing to trade to suit your requirements, If a design isn't close to what you need you're better off finding something else!

 

I am making this post with great trepidation as I know it will set the cat among the pigeons. However i feel it has to be said.
A member on this thread asked me to comment on this design and so I sat down and contemplated on it for several days. This is what I came up with:-

Firstly I am alergic to flat bottom boats. They are less efficient in terms of vortex drag and wetted surfce drag than round bottoms. Fine for smooth water sailing but can pound badly in choppy conditions.
Also there is no Bilge, whch means you are walking on the bottom surface of the boat and inevitably it gets wet. However they are easier to make.
Secondly the flat beams (only 1 1/2" thick) means that, even if they are strong enough, they will flex, and since the main mast shroud is attached to the outside of the floats and the lower shroud is attached to the cabin sides it affects the stiffness of the rig, in that the top half of the mast will be allowed to wave around in rough conditions.. (Someone else on this thread made this same observation). Waterstays would prevent that.
All three hulls are in the water. and since the floats have a deep V section, the boat will have a jerky sideways roll with athwartship swells and passing powerboat wakes, (just like the Piver Nugget). Also the little attempt at asymmetry at the float keels is an unnessary complication as a it was well established by Edmund Bruce and confirmed by Derek Kelsall in 1966 that the hulls in multi's should not be designed to resist leeway. That is the job of dagger or centreboard.
The cabin sides angle Out,- Why ? And (unless it is shown on the plans) there is no walkway to the foredeck. I am averse to having to climb over the cabin top to go forward in a rough sea situation.
The cockpit is small and has no lockers for handy accomodation of items. There is only one bunk, (snug double),narrow but long, suitable for two tall skinny people Lol.!!
The cabin is small and claustophobic with only two portholes on the sides and apparantly no window on the flat front. The centreboard actuatiuon tube sticks up right in the middle of the cabin, which will be awkward. The centreboad case is right under the head of the bunk and could prove to be noisy at night when on a mooring.
The boat is all wood, which is a good thing if you live in an area where good wood is available and cheap. It needs to be built on a strongback which is it'self an extra consideration and takes time to to set up exactly level and square, unless you have a dead level concrete floor to build on and can dynabolt the longerons directly to the floor.
In my opinion the mast is too far forward and the big rig will tend to depress the bows in strong winds.
On the other hand it is good that the bows of the floats are level with the main hull stem.
About the swing arms.
A GOOD IDEA, but I am a bit nervous about the location of the lock bolt. The leverage on that bolt is enormous when the boat is going fast in rough water. I am not worried about the bolt, only the long term effect on the bolt hole and the possibility of the stress reversals eventually splitting the wood of the plank. It is the only thing preventing the crossarms from folding back. and I would much rather see a restraining wire doing that job.
In my opinion the immersed area of the centreboard is inadequate for good windward sailing. The rule of thumb for CB area is 2% of the projected sail area. IE:- Mainsail and Fore Triangle area. The centreboard down area is only
2 1/2 sq ft. It needs to be 5 1/2 sq ft for that maximum sail area.
I am not trying to put people off this boat. All designs are a compomise, and this one is a good effort. I am only going on the info obtained from the three view and interior drawings off the thread. The actual plans may show different approaches to these opinions, so I am not making any comparisons.
My views are based on 48 yrs of building, sailing, crusing and racing Trimarans and Catamarans and so I am probably a bit opinionated.
So now you can "Flame Away" and Let me know what you think.
Cheers. OS7.

 

I think you made a detailed critique based on your preferences and experience so cheers paddy. My old vagabond has immersed floats and we are very comfortable in an anchorage where the monos are rolling and hopping and the new tris bouncing from float to float. In fairness it is probably because our floats are more slender than Piver's that the motion is gentle but the Brown amas don't look too wide for comfort. If flat bottoms are kept narrow like a dory it is hard to tell they are there. The pivot bolts and lock bolts might pull out of the end grain over the years so maybe a composite bushing treatment is in order. I'd like to see one sail alongside a searunner 25 and small seaclipper for comparison so here is to the builders!

 

I took a quick look at those plans again and think the asymmetric amas are to send the buoyancy outboard to add the effect of more beam rather than resist leeway. They are the wrong shape for that....Dick Newick's dynamic lift amas come to mind for lee way prevention. The centerboard could easily be lengthened but I think they are counting on the deep immersion of the main hull for some area. The diamonds should stiffen the rig somewhat. It looks like there is room for a vertical main hull step for more bunk room but again it might be noisy and would add complexity. It is interesting to compare it to Ed Horstman's small folding tris but the Marples/Brown gets the low tech award, it will be interesting to see how it sails. While the cabin does look a little odd inside the flare would add to the visual space for those wrestling claustrophobia.

 

The thing about a boat like this is that there isn't any way it is going to be perfect. But there haven't been that many simple tri plans put out there recently. Cats have several advantages over tris where simplicty is concerned. They tend to be simpler to build, less hulls, and overall leveler, parallel and level hulls work fine, just for instance. Less seriously cat builders have the highly successful Wharram brand to fall back on, and it is possible to make a handsomeish cat with very plum plywood sides and still have it look similar to the best of breed, while a curveless trimaran tends to look a bit awful. Also, a tri tends to be designed for various comples needs like racing, or trailering, where simplicity is hard to acheive.

So what would a simple tri look like, one will all kinds of compromises, just like the Wharrams. Brown and Marples have been making them for years, and are almost the only ones left. They know what they are about, and I wouldn't worry about the structure of anything John Marples touches.

I do have three largely personal quibbles. First I sometime think they are too simple. I know I just went through all that stuff about why they need to be, but when I hear Jim go on about using pressure treated and tar, I kinda loose focus. Second I do wonder a little why they don't move them down the timeline a little. I do understand the geometry of bow overhang, flare, etc... but I would want a hull of this kind to make a little better use of the small size. Finally I do think some of simplicity has to do with simplicity, some has to do with cost, and some has to do with making the build easier for newbies. I can do without the first and last. I design simple largely for cost, I don't really find I save money or time by avoiding stuff like stressformed amas.

 

Hi ThomD/
I see you are from TO.
What is happening in the TMCC these days. :?:

 

Have a look at this guys boats, cats and tris, I think they tick all the boxes described above, http://www.delaveaumultihulldesign.com/

Cheers,
RR.

 

Yeah. Jamez is building one.

 

BILL.
How are you getting on with your build. ?
Do you think you will have it finished by Christmas.??
Please keep us up to date with your progress as a lot of us are really interested in this little Tri.

 

Sc24mc

G'day Paddy,

I contacted John Marples and asked what he thought of me using the 19' hulls from the Quest B3 Cat for the amas on the SC24MC, here's a copy of his reply to my query:
Quote.
Bill,

The cat amas are worth a try. Not much lost if they don't work, but it will get you to the water faster. Generally, beach cat hulls are not designed for the loads experienced by trimarans. The cats are lighter, although faster (maybe) but only have to carry the weight of the crew. The tri has the additional weight of the main hull. Tornado cat hulls have been used for performance tris, but they had to be strengthen with added internal structure to make them suitable for all conditions.

Good luck with your health and boatbuilding in the new year, John
End Quote.

So Paddy, as a boat builder, what do you think of me using the 19' Cat hulls as the 24' Tri amas? How should I go about strengthing them and/or any other ideas you may have.

I plan on using the 29' mast, boom and sails from the Cat on the Tri...Anyway, I would like to get started just as soon as the bleeding hospital finishes with me in early January...We'll see how I go

Cheers,

Bill

 

Bill,
I am not conversant with the hull construction of the 19' Quest beachcat.
If it is of the "Tortured Ply" type, like the Tornado, then it wouldn't hurt to run a 3/4" (19mm) stringer from stem to stern at mid height, to take the extra compression on the sides. A doubler at the gunwhale where the crossarms attach would also help to spread the load when driving into a head sea. Of course you have to reinforce the deck where the crossarms pivot.
Other than that I don't see why they wouldn't be just fine. IMHO.
Cheers. Paddy.

 

G'day Paddy,

After going over everything to do with building my SC24MC, plans, updates as they are sent to me, cost of all materials/gear required, and time in building, I also took into consideration all the views given on the forum and, anything else I could think of.
I got back to thinking just why I wanted a boat, and came back to remembering, I want a boat that I can get out on the bays in, safely, to learn to sail, do a bit of fishing and do a bit of exploring along and around the coast, in safety, and, I wanted to get back on the water to do those things ASAP.
I would have my little dog, Timba, along for company, (his mate died a little while back) apart from him, I would, most times, be on my own. So I bought the plans to build my own SC24MC. I believed the SC24MC suited my needs to a T, and I reckoned I could build my Tri' in around three months, working full time on it.

That was before I found I had a few more health problems than Paddies donkey. (no offence intended Paddy) Anyway, after my last visit to hospital and later going over everything I could think of, boat related, I decided, if I want to get back on the water ASAP, building my own boat was not the answer, I should instead have a look at, suitable for my purpose boats for sale. So I did that and...I was lucky enough to find a good boat, in the price bracket it would cost me to build my SC24MC, using the best materials.

The boat, a mono, Compass Careel 22, had only been listed for a few days when I spotted her, to cut to the chase, the Careel 22 is now “my” boat. I pick her up and bring her home next week.

What will I do with the SC24MC plans? I don't know! I may keep them and start building come our Aussie winter, or I may offer the SC24MC plans, the 19' Cat and trailer, for sale as a package deal. One thing I do know...Should my wife decide she would like to come out on the boat with me and me dog, (most unlikely) she'll be more at home on/in the Careel 22 than she would ever be on/in a SC24MC. (Women in our age group are funny that way )

There you have it, I'm now the proud owner of a Careel 22. I believe that ends me posting to this thread...Unless I start building the SC24MC...Well...You never know what's in store for you, do you?

Bill