Searunner Build Time

[8472]

Has anyone here ever built one of the larger Searunner variants from scratch? If so, can you estimate the total man-hours required?

And while we're on the subject, what would be involved in scaling the 40 up to 50 feet? Would that be a fairly straightforward process for the designer?

[Fore and Aft]

It would be impossible to estimate how many hours it would take you to build a Searunner trimaran. It really depends on your skill level and what you call an acceptable level of finish. The wife and I built a 10 meter multi chine plywood yacht in 18 months working only part time on her. That was with a spray painted exterior and rolled paint interior. Perspex cupboard doors and no varnished timber work anywhere so my joins did not have to be perfect.
As for scaling up to 50 feet, you are creating a whole new boat really. You could maybe get away with it on a mono, but on a tri you would want extra beam and rig size to go with the increase in length.
Where’s GordMay?
Cheers

[roverhi]

If we are talking the Jim Brown Searunners, believe the 40 was an expanded 37 with 3' added to the stern. Trimarans don't have spacious interiors but they are really large boats both in width and sail area. Would think seriously about how you are going to handle a 50' boat.

Don't know how long it would take to build one but it's going to be a lot longer than you think it will take. We built a Westsail 32 from a bare hull and launched in a year working full time 12/7/365 and another 6 months to finish it working part time. Other than commisioning, outfitting and maintaining two sailboats and building a sailfish board boat as a kid had no boatbuilding experience. A guy who'd built 3 sailboats gave me some advice when I was too committed to building the Westsail to back out. "If you want to build a boat, build a boat If you want to go sailing, go sailing. Don't try and do both as you'll accomplish neither."

Don't want to give you too much encouragement but when we were in SoPac back in the last millennium, Searunners were the most common boat out there. There were 2 31's, two 37's and a 40 that had all been built and sailed when the owners were shy of 40.

[8472]

Thank you both for your feedback. I understand that scaling the design up is not simply a matter of tacking on an additional 10 ft of length; I suppose what I should have asked might have been how major of a task I'd be commissioning a qualified designer to do, scaling the gross dimensions to 125% like that? And roughly how much should I expect to pay for such service?

Come to think of it, I might have better framed my other major question as well. How quickly could one extremely committed young(ish) man conceivably build such a vessel, assuming that neither appearances nor luxury were priorities; that he were competent, methodical, and well-prepared; and that the necessary materials and tools were all readily available, along with additional manpower whenever it might be really needed? Assuming that he were both willing and able to work ~12 hours a day, every day, could such a craft be completed in eighteen months? Twelve? Six?

[8472]

Originally Posted by roverhi

We built a Westsail 32 from a bare hull and launched in a year working full time 12/7/365 and another 6 months to finish it working part time.

From what I've just read, this is a monohull which was sold as a complete hull but nothing else. I've also read that the hull itself is typically the fastest phase of construction, and that most private builders get bogged down after the major hull assembly is completed; would you say that this is accurate?

[8472]

Originally Posted by Fore and Aft

The wife and I built a 10 meter multi chine plywood yacht in 18 months working only part time on her. That was with a spray painted exterior and rolled paint interior. Perspex cupboard doors and no varnished timber work anywhere so my joins did not have to be perfect.

This is encouraging to hear. My goal for this planned vessel is for her to be an extremely robust, very long endurance liveaboard cruising ship, intended to spend the vast majority of the time at remote anchorages, but appearances are the very least of my priorities; spartan austerity suits me just fine.

[Fore and Aft]

People get bogged (No pun intended) down boat building for lots of reasons. The hull stage is usually the best since you are fresh and you can make large visible amounts of progress. Once you are on the inside its easy to spend the week working and see no progress at all. If you keep away from the fancy joinery and finishes then you can still build the interior quickly. It will just hurt your resale value when you come to sell her. That was no drama for me as I wanted to be on the water and not worrying about future boat value.

Have you read this book? I kept a copy close by and would occasionally read it if I felt I was starting to get to proffesional!
Cheers
Buehler's Backyard Boatbuilding book by George Buehler

[Boatguy30]

Depends how you built it?
Old school with many interior surfaces not even painted or West System style with all surfaces fully sealed in epoxy.

Old school, you could do a SR 37 in perhaps 2500 hours. Fully epoxy sealed probably 4000. Double that time if making 50'

Have fun!

[8472]

Originally Posted by Fore and Aft

People get bogged (No pun intended) down boat building for lots of reasons. The hull stage is usually the best since you are fresh and you can make large visible amounts of progress. Once you are on the inside its easy to spend the week working and see no progress at all. If you keep away from the fancy joinery and finishes then you can still build the interior quickly. It will just hurt your resale value when you come to sell her. That was no drama for me as I wanted to be on the water and not worrying about future boat value.

Have you read this book? I kept a copy close by and would occasionally read it if I felt I was starting to get to proffesional!
Cheers
Buehler's Backyard Boatbuilding book by George Buehler

I've added both editions to my high priority list, thanks!

[8472]

You've all been quite helpful; thank you all. I'll keep you posted as I get geared up to assail this project. First, however, I've got to read up, take courses, and buy something much more modest with which to... well, to get my feet wet, so to speak.

Originally Posted by Boatguy30

Depends how you built it?
Old school with many interior surfaces not even painted or West System style with all surfaces fully sealed in epoxy.

Old school, you could do a SR 37 in perhaps 2500 hours. Fully epoxy sealed probably 4000. Double that time if making 50'

Have fun!

Specific numbers, however "ballpark", are always reassuring to me. Thank you.

[Dsanduril]

From personal experience, a Cross 40 took 2.5 calendar years and approximately 7000 hours of full time + work for one person (mid 30s age), with weekend help from the family. The Cross is cold-molded, which is a bit more complicated than the Searunner, but the hulls took 6 months of the total time to complete, so not a huge amount of time to save.

That’s one data point.

[Ken Fry]

I don't think Jim Brown is still designing. If he were, he'd be the best bet for scaling up the design.

Scaling a boat design is seemingly simple if the boat already exists in a program like Delftship, etc. But you then end up with not much more than simple lines drawings, and you have a long way to go to actual construction drawings, partly because many things in a boat do not scale up with the boat size: counter heights, seat heights, berth sizes, etc, etc. By the time all is said and done, you might just as well have started with a clean sheet. Many shape-related things also don't scale in a simple way -- you don't necessarily want 1.25 times the freeboard and 1.25 times the waterline beam (and so forth) when you go from 40 feet to 50 feet.

(30 foot boats have 6'5" headroom. 60' boats do not have 12'10" headroom.)

If you look into displacement length ratios, sail area displacement ratios, etc you will find that they also don't scale in the way that you might think. So again, you might just as well start from scratch.

It costs at least as much to design a boat for owner building as it does for professional building, and designs that come with "instructions" should cost more yet -- because there is a lot that a professional builder does not need to be told.

So if you figure on $1,000,000 being the cost of a simple production 50 foot tri, then you could figure on perhaps 10% of that as a design fee -- or much more for some designers, and less for others.

I've built several quite small boats (general west system) and am now building a 31 foot wing-powered catamaran. It would probably take me 4 years to build a 50 foot tri... longer if I'm doing a lot of inventing along the way. If I had to work outside, without heat and air conditioning, it would take far longer.

You have to really love the building process to spend the time necessary to build a large boat. Everyone is different, so you may be OK with the time, effort and cost of building a big boat. I love working with wood, but find 30 feet to be about my limit for time between imagining and sailing.

If you haven't built boats, first build a kayak from plans (not a kit) and weigh it. (It is likely to be 30-40 lbs) Take the time to build it and multiply that by the ratio of weights (50' boat/kayak). That will give you a feel for how long the tri will take to build.

[Sand crab]

Do you have a place to build this right next to the water because renting commercial waterfront property ain't gonna be cheap. Also you'll need a covered space and possibly climate control. Freezing temps and boat building resins aren't the best of friends.


I don't know why you are focusing on Searunners especially when there aren't stock plans. Try Ed Horstmans designs. He's got plans for many big tris and cats. Ed Horstman Designs


There is also Kelsall plans but he's all cats. My advice is to build a cat or better yet just buy an older cat or tri and fix it up as you go.
Multihulls - Multihull boats come in three main types - Catamaran, Trimaran or Proa. Catamarans have two normally equal hulls while T

[Kaimana]

I built my 37 by myself in 1970 in Santa Barbara, outdoors, with no shelter, in one year, at the age of 18. She was my second SeaRunner, as I'd built a 25 when I was 17.

It had all painted interior surfaces, aluminum spars by Famet Marine, I made the sails, steering wheel, did all the stainless steel welding (for the kickup rudder box, etc), did the rigging. I earned most of the money for the boat by working part-time during that year.

(Below) My SeaRunner 37 Spice off Kawaihae on the Big Island

I did it by wanting a SeaRunner 37 more than anything else in the world. I also did it by not having girlfriends, not drinking alcohol, and not taking a single day off. I worked my skinny butt off! It was worth it; later I sailed that boat singlehanded to the Marquesas and around Hawaii for a year before selling her to build a bigger tri.

See our site here for the stories of these boats: https://oceanpeople.org/, under the menu pulldown "Boats We Built".

My family is building proas now, some rather big ones. Love multihulls, have nothing but great praise for Jim Brown; his boats saved my life several times at sea.

You can still purchase stock SeaRunner plans from John Marples, who is in partnership with Jim Brown, who is retired. Email John at John Marples <marplesmarine@gmail.com> for details; I'd imagine you might be able to hire him to answer any questions you've got about building SeaRunners, since he built his own 37, won the Multihull Transpac in it, and has designed and been involved in building countless other tris and cats over the years.

With Warm Aloha, Tim Mann

[Pauls]

Small changes in length can often be accomplished simply. Going from 40' to 50' is not a small change. This is a major change in all respects. The 50' will require heavier scantlings, meaning that the structural elements of the boat will need to be heavier. A larger rig and increased righting moment will mean significantly greater loads on the rig and the hull the rig attaches to. There is a fair amount of work here and you will need a pro to do this work for you as it is technical.

I want to also draw attention to Roverhi's very good point about handleability of a 50' tri. You are going to have large, powerful and heavy sails to deal with. I'd caution you to be really sure you want a boat this size before you build one.

One other point is that a boats weight goes up (generally speaking) as a cube of its increase in length. So you would expect a 50' to weigh 1.95X as much as a similar 40'. That means double the amount of material to buy and about double the amount of work to put it all together. Believe me, bigger boats take a lot more time and work to build.