Modernising a Horstman Tri.

Hi People,
I have been looking at a multihull designs for a while now waiting for "the one" which ticks all the boxes.
I have looked at the Kendrick Scarabs, I have plans for the Buccaneer 24 and have looked at Simpson catamarans like the Backslash.
I am a single man with two children 7 and 10 and various female friends .
I do not need a speed machine but do wish to utilise this aspect of multihulls.
I am pretty convinced a trimaran is the format I like as the size range i'm looking at suits the tri layout, further I prefer the motion of a tri compared to a cat.
The size range would be a max of 28ft folding not required.
Buying secondhand on the West coast of Australia is simply not an option.
And so we arrive at the Horstman 24, while an older design it is a type that has great appeal due to its accommodations and heavier displacement (load carrying) And is a style that has been neglected, even abandoned by contemporary design.

However there are aspects of this design that could do with some modernisation and it is these aspects that I seek your advice and opinions.

These are the issues as I see them.

I would stretch the existing design to approx 26'. The intention being to include an enclosed head which could be worked in with a daggercase in the main hull rather than the boards in the floats as designed. Would also address rig changes, see below.

Rig, masthead rig needs to go ! I am thinking fractional with self tacking headsail, perhaps even a ballestron for sailing simplicity. What is involved in converting masthead to fractional ?

Floats and overall beam. Most modern designs carry more overall beam and longer floats ?

Hull shapes look to me a bit fine in the ends, the main hull looks like it could use some more volume aft and a flatter run to counter pitching. And perhaps a more rounded bilge overall.
The floats are very fine and quite pointed compared to there modern counterparts and look like they could use an extension aft, and perhaps more rounded bilges.

As you can see I have pretty much redesigned the boat !

There is very little on the net regarding the sailing qualities of these yachts but I have been able to gain the impression that they are solid, seaworthy and track well.

I realise it's a bit like turning a Warram into a Schionning but my question to you all is, what is worth doing and what should be just left as is ?
When I have a more clear idea where I want to go with this I will put it to Ed Horstman.

Here are some links of the boat,

http://www.edhorstmanmultihulldesigns.com/triplans/tri24.php
http://www.yachtsnet.co.uk/archives/tristar-24/tristar-24.htm
A further thought on this was to get a more modern design of say 30' (Farrier/Kendrick) and compress it down to get the displacement and put the Horstman deck/cabin layout over the top.
The various thoughts and opinions on this will be most interesting !
Cheers,
RR

 

Why move the daggers? The cabin/wing wing of the Tristar handles the loads well. More beam and longer amas will also add weight reducing payload. As it is you can't bury the amas because of the buoyancy of the deep wings. I'd suggest building it close to the plans to get sailing sooner, the ladies tend to find other boats to sail on if you take to long....Ed will probably pin back your ears if he thinks you're hashing things up!

 

Cav,
Simplicity of one dagger and having it in the main hull, where it is easier and safer to get too.
Modern materials and resins would compensate for extra weight, these were designed when polyester and woven rovings were all that was available, but i do see your point.
Stretching the floats aft is no big deal just space out the frames a bit

 

On a boat that small I'd still keep the boards in the amas for the cabin space. With up-down lines you shouldn't need to go out to them....which isn't really a worry with a deck like an aircraft carrier! I haven't heard of pitching issues with these boats but I haven't sailed on one, maybe you can find a current owner. Ed has one of the older 24s in his airplane hanger and could probably set you straight about performance while pinning your ears back!

 

On Ed's website he says the designs are constantly updated with input from the sailors so it seems worthwhile to send your thoughts in. Looking at the layout again and thinking of your stretch to 26 feet I'd consider taking a page from Nicol and putting the head in the stern behind the cockpit with a slightly raised aft deck. Sitting headroom but a hatch could let you stand. A crawl space under the cockpit could keep the kids off the deck, not sure if the 24 has a bunk there but something could be worked out. The cockpit might have to be a little shorter but it would offer the most privacy and ventilation. If you used the same maststep for the fractional rig the ama daggers could be moved slightly to compensate if necessary. Then you don't have to change the structure much.

 

I will try to dig up some info on the 27'8". Someone compaired the tristar 27'8", 31', 32' , to the Cross,es and Searunners same size range and larger. When I get started I will change a few things like adding a dagger board rudder. I may add 4% L/B , Ed said I would,nt have to beef up the scantlings but also said he would,nt scale up. There are enough problems with scaleing up without changing the design, you could end up with a boat that is a waist of money. If I wanted to scale up the 24 then I would look at the 25', 26' , and then settle on the 27'8", only another 1'8" more and the added vol. you want. My frames are cut for wood,but I will be building with foam, so adding 3% to 4% L/B will put me about right compensating for the added material thickness . If you build the 24' with foam and cut the frames for wood you will add some vol. without scaling. Let me get off line and try and find Fred,s email add. Rick

 

Send Fred an email at fredmgoldfarb@hotmail.com . He has me a list of things that will help moderize the 31. Rick

 

Hi rberry,
Thanks for your comments.
While I do wish more volume in the 24, I think the last thing these boats need is a lower L/B in the hulls !
There are two reasons for stretching the 24' to 26', the first being a bit more size/volume the second being to increase the L/B to a finer hull.

 

Your premise is fair enough, but I find your points below perplexing.

I would stretch the existing design to approx 26'. The intention being to include an enclosed head which could be worked in with a daggercase in the main hull rather than the boards in the floats as designed. Would also address rig changes, see below.

Why not start with the 27/9 ? It's an absolute tardis and quite a bit bigger than the 24. Horstman's boats are proven ocean crossers and he stuck teh daggerboards out there to make more rrom in the main hull.

Rig, masthead rig needs to go ! I am thinking fractional with self tacking headsail, perhaps even a ballestron for sailing simplicity. What is involved in converting masthead to fractional ?

If you have to ask...Why don't you like the masthead rig ? They are not the ideal choice for racing but they work very nicely for cruising. I doubt you'd notice a difference in overall speed on a passage. Mastheads have active backstays which offer lower sidestay tension and very good control over mast bend. They may not be fashionable but they have real demonstrable advantages in a sea boat.

Floats and overall beam. Most modern designs carry more overall beam and longer floats ?

And a little further forward, but again they have followed fashionable racing practice. If your cruising you won't be sailing at 10/10ths. Even when it's safe it's uncomfortable. You'll probably find his float volume is a little lower aswell. Note his soft V hulls. Not as low wetted area as rounded but much more comfortable in a seaway.

All this stuff is a compromise. Ed Horstman has designed a superb range of tris to do a specific job. It's no use buying a premium hammer if you want to cut a piece of wood in half. If you want a roomy capable cruiser they are amongst the best. If you want a non folding rocketship have a look at Kurt Hughes stuff.

I don't understand why length is a deciding factor rather than say cost to build or displacment or boat weight ?

2c

 

Guzzis3,
Thanks for your reply, easily 2c worth and I appreciate it.
I am considering the 27' 9" and have the study plans, my main concern with going to the bigger boat is cost, everything gets more expensive even with a small increase in size.
What isn't apparent from the website is that the 24' like the 27'9" also comes in a flared hull version and I believe this would give me the room I require. Stretching the 24 would give me the room I require and fine out the hulls somewhat whereas going to the 27'9" takes me back to the chunkier heavier cruiser L/B. I don't want a cruiser/racer but a little extra performance can't hurt.
I am not fixated on an enclosed head but people do prefer them and I simply saw bringing the dagger case into the main hull as a "two birds one stone" thing where the case would be one wall of the head/shower.
Fractional rig, I am familiar with, I have crewed on monohulls with both, and given that I will be sailing shorthanded I would rather reef a main than change a headsail, further forestay and swept back side stays is simple. I realise a roller furler is an option but I'm not convinced (yet). But you have me thinking !
I am well aware that these boats do there job well the infrequency with which they come on the market is testimony to that, owners appear to love them.
On overall modification, I guess I'm thinking that since these boats were designed multihull development has really developed, particularly in hull shapes pitch control, float volumes shape etc and am thinking that if I build from scratch it would be a shame not to incorporate any of the lessons learnt. But I hear you !
Cheers,
RR

 

The 27'9" s numbers compare more in line with the 32', so there is some speed to it. Email Fred and ask a few questions about the 27'9". Rick

 

If you stretch a design for more speed you keep the same midsection and lengthen the ends for smoother transitions. I sail with a masthead rig with furler and it is far faster to roll up some jib than reef. The old wing deck tris are stiff enough to keep a tight forestay, fractional rigs started showing up with the openwing boats. I like the tristar 26 folder and hope Michael posts more on his build soon.

 

Horstman tristar MT26

I am currently building the MT26, after studing the plans very carefully. I'm just building it to the original spec's. This is going to be my best, most fun boat I have ever built. We are planing to cruise the Florida Key's and all the southern gulf states. Trailer launch and save a lot in travellift costs. Hook it up to the truck and travel, no slip fee's. Pat Ross @ multihull dynamics will give you a multihull comparison for a small fee. He already has the 27-9 data on the site. I will be posting pic's of the build on his site and my blog.
Have questions ? just yell, I'll try to help where I can..Michael..

 

Hey 'Doc'-gub. Fractional rig - 'Sundancer' 1967 - rotational mast - fractional rig - 500 sq ft - fully battened mail - slab reefing - - 150 sq ft jib on 40' x 17' x 5300 lbs cat. Can't remember when the rest of the world finally caught on ???

RR - 'roll-up' jibs - are at very best a 1/2 compromise - - better to have 2 'roll-away' independent head-sails ! ! ! At least then you'll get the correct shape for the wind speed & not 'blown-out' a sails ! ! Ciao, james

 

We have a staysail for higher wind ranges...up here the wind changes in every channel so you'd wind up pretty tired slab reefing. We lose less ground rolling up the jib than luffing the main to reef, but don't mind me I've sailed a fractional rig on a mono for over 25 years in these waters and compared. The Gougeon roller boom is about the only way to make it as easy.