New to Boatbuilding... Need Help

[Viper2]

Hi guys,
My father and I have always been interested in building a boat or car or something of the sort, and now have come to the conclusion we want a modest Trimaran. We are working on a Modest Budget as well, so we are trying to figure out what the best route to go is.

Now heres the problem... although I am in Physics AP and Calculus AP as a Senior in HS, I have not a clue as to the parts of a boat. I do however understand the concepts behind the Trimaran.

What I would like to do is ask you guys, as experienced builders, what our best bet is for a 3 person Trimaran to run on a fairly open lake? I say three because my father is a hefty 6"6' and 350 lbs and so I would like to be able for both he and I to go sailing.

I am hoping this to be a fairly fast boat as well... at least giving some medium powerboats a run for their money. so is there any hope for us at all????

Thanks,
Cameron

[fhrussell]

Are you following this thread....? Jump in!

Trimaran Design

[Chris Ostlind]

Originally Posted by Viper2

... at least giving some medium powerboats a run for their money. so is there any hope for us at all????

While I don't see that in the equation, Cameron, I do see the potential to totally wax the existing monohulls, along with many of the other mulithulls, on your body of water on a regular basis with a three-man trimaran.

These boats are really light (or they should be) with acceleration potentials and offwind sailing speeds well beyond those of the monohull boats with which you may already be familiar.

You'll have to select a design that can handle the three man displacement, plus the boat weight in order to have a really fast boat... they are out there.

If your design criteria changes to include overnighting and casual beach camping, then there is a different boat in your future, as all-out racing machines have little, to no, accommodations for anything beyond the racing application.

Sit down with your Dad and come up with a proper design brief as to the focus of the boat you wish to have as an end product and go from there.

There are many considerations for a boat of this type and if you describe that list of needs, you will be able to search-out a boat that meets all, if not most, of the criteria points for your passion.

Let me know if there is anything that I can help you with along these lines.

Chris Ostlind

[Viper2]

well I'm not really looking directly for a racing boat.. I just want something thats averagely quick, but I don't really need any kind of interior being as this boat will normally be on Lake Norman, a massive lake but never the less still a lake.

But I did chose to look into Tris vs. Catamarans because I have often heard they are naturally faster on the water. However, are Trimarans much harder to build than Catamarans?

And what is the most effect way of building a Trimaran... I am almost completely unfamiliar with any type of boat construction other than wood+nails, and once I reached the glass and Epoxy stage I would have to rely on others for help lol.

[Chris Ostlind]

Viper2,

The most commonly used material for boats of this type is marine plywood. That would probably be followed by cedar strip built boats and then foam cored boats after that.

There's another thread on this forum that shows a really amazing trimaran main hull built with a foam core and vacuum bagged carbon laminate set into epoxy resin. 22ft racing tri design This will be a very fast boat based on the construction and design skills of the builder and his previous familiarity of the material and process requirements. It is not designed for cruising style applications... more a day sailing speedster within which you can store useful stuff in the cabin structure.

I see you needing a boat that has some of these characteristics with a significant dialing-back in the materials and build style from the all-out carbon/foam build style so that it can be built for quite a bit less money and still give you a performance potential that creates a high level of satisfaction. To that end, I would lean towards a lightweight, marine plywood boat with glass/epoxy laminate skins on the inside and outside for strength and watertight integrity.

A catamaran is easier to build if only because it has one fewer hulls to construct when compared to a trimaran. For truly lightweight, fast sailing, it is really hard to beat a cat. For fast sailing purposes, a cat is lighter and it can be built far more quickly than can a trimaran... for less money.

A cat, at the sizes that you suggest, will likely be a wetter ride and need to have more attention paid to the sailing than will a tri. You will be able to tow it to the launch ramp with a smaller vehicle and it will go together quickly with standard tools.

A tri will be heavier to tow, can be made to assemble faster than the cat, (if it has folding amas) and can be ready to sail more efficiently for the same reasons (folding amas if part of the design). If the tri is not a folding design, then it will take longer to assemble, as there are likely more parts to haggle with on the launch ramp.

For boats that are going to be left at a lake all season long, for instance and then stored away for the winter, it matters little in the grand scheme of things. The time differences in assembly are spread out over the entire season and they become a very small part of the overall use period.

Like I said before, you guys need to sit down and hammer-out the important issues for a boat of this type. A three man cat can be made to handle a nice amount of beach camping supplies while still being very fast on the water. A tri is easily adapted for this same mission.

I suggest you take a look at some of the cats and tris in the 20-24' range for ideas as to how you would like to operate your boat. There are some interesting designs out there that could work for you as well as be fairly easy to build and transport.

If you need to ask any more questions about the type of boat which would serve you best, don't hesitate to write me here, or send me a private message, or write directly to my email address at: Chris at Wedgesail dot com

I'd like to see you end up with the best possible boat for your needs,

Chris Ostlind

[Viper2]

one major problem I have realized is that although I am located close to a massive lake... there are no naval stores, nor stores around that sell marine grade wood. after doing some research online the closest place that sells marine plywood is in Virginia Beach, Va.

What kind of wood is best suited for a multihull that I can access a little easier than Marine ply? This boat will be maintained well and I know that because I dont use Marine ply is will not sustain as long as it would with other woods, but what might be a good idea to use?

[Chris Ostlind]

Western Red Cedar, Atlantic White Cedar, Northern White Cedar and Cypress are fairly standard building woods for this type of strip-built boat.

If you can not get these building woods locally, then you will probaly not be saving any money when compared to purchasing marine plywood from the nearest supplier and having it either trucked to your location, or picking it up from the local lumber yard.

If you do find a supply of one of the above woods, then you are stating your interest in building a strip built hull as opposed to a marine plywood design. This is not a big deal in the grand scheme of things, but it will, typically, require more time to construct.

A strip-built design will provide you with smooth hull curves compared to the multichine, angular effect you would get from a plywood design.

Like anything in boatbuilding, there are trade-offs for each approach.

Chris

[fhrussell]

Viper,
I wouldn't worry so much about buying ply locally. Call up any boatbuilding supply house or ML Condon in NY or Boulter in Mass. They ship orders all the time. I can get marine fir ply at one of my local places, but I order Ocume and other BS1088 from Condon and others. I once bought ply from a place in Oregon. Their price even with delivery was better than the local guy and the quality was just as good, if not better.

[Viper2]

yea I haven't been able to find any suppliers of those woods around so I would have to order it from out and about.

If I were to want to replicate the DragonFly 600 design, how hard would it be using the strip method and what kind of money am I looking at spending?

[Chris Ostlind]

A lot depends on how you buy all the hardware elements for the boat, Viper2.

The wood, epoxy and glass component elements are going to run you about $4K, it's the other stuff that is going to really spin the cash register, though.

If you buy carefully and make a few compromises between getting all new hardware and maybe some stuff that is lightly used, you could conceivably get away with a total bill of something like $8-10K

If you are on a really hard-nosed budget, you should be looking at a good pair of beach cat hulls, a used Hobie rig, or other beach cat with suitable sail area and rig type. You can pilfer almost all of the hardware off the used market, carefully picking and choosing the stuff that isn't hagged-out from poor maintenance, or years of hard use. In fact, you may want to consider the purchase of a complete beach cat in the proper size range and use everything off the cat and sell the rest or hold it in the garage as spare parts.

If you are using the D600 as your model, then you see that they spec a rig in the low 200 sq.ft. region. This will make for a decently quick boat for two-up sailing without getting yourself onto the ragged edge from flying a lot of sail area. I just built and tested an 18-foot trimaran with a Hobie 16 rig and it performs as nicely as one could want from a sporty, recreational beach trimaran.

The D600 also flies a nice, assy spinnaker, as well as at least one trap wire. You could make the sail area comparison with a Hobie 16 rig, along with the trapping loads, but the spinnaker would put some real strain on the mast (along with the wider beam of the tri) that would require you to install a spreader and diamond wires. Not a big deal, if it is done correctly.

More horsepower can be had with a larger rig, such as you'd find on an H18 or H20, if you have the skills to handle the larger power potential. Both of those masts are standard with spreaders, so no retrofit is required.

Much of the sail handling hardware could come directly out of the beach cat market, along with the rudder system and even the trailer, so you won't have to hunt for a spendy trailer to haul the boat around.

Chris Ostlind