I'm having rowboat built - is it overpriced?

[arsinoe]

Originally Posted by Rick Willoughby

Have you done any rowing on a calibrated machine. If you know the power level you can sustain I can give you estimated performance for the boat you have nominated and an optimum hull for the same displacement and power level.

That would be great (really great). I use a Concept 2 rowing ergometer. Last week I was on it for 30 minutes and achieved an average of 223 watts (once I was properly warmed up, I was putting in up to 245 watts). Two days ago I was on it for an hour and achieved an average of slightly over 200 watts.

I believe that, with another year or two of training, I'll be able to sustain 250 to 275 watts for an hour (this is just an educated guess).

The boat's main purpose is rowing outings of 30 to 40 minutes' duration with one or two passengers on board.

@apex1

Thanks for the e-mails and info; I'll have to digest it all, but you will definitely be hearing from me within the next few days.

[rasorinc]

How about something like this for under $5,000.00 US
https://www.boatdesigns.com/products.asp?dept=190

[Guest625101138]

Originally Posted by arsinoe

That would be great (really great). I use a Concept 2 rowing ergometer. Last week I was on it for 30 minutes and achieved an average of 223 watts (once I was properly warmed up, I was putting in up to 245 watts). Two days ago I was on it for an hour and achieved an average of slightly over 200 watts.

I believe that, with another year or two of training, I'll be able to sustain 250 to 275 watts for an hour (this is just an educated guess).

The boat's main purpose is rowing outings of 30 to 40 minutes' duration with one or two passengers on board.

@apex1

Thanks for the e-mails and info; I'll have to digest it all, but you will definitely be hearing from me within the next few days.

The attached shows the lineplan for roughly optimised full displacement version. I chose KMT of 0.7m as this gives reasonably safe conditions for boarding. This sort of hull works well with a double chine construction. You get nicely faired lines and very little compromise in performance.

By the way if I was going to the expense you are going to with the design and build I would certainly consider using modern materials such as carbon fibre over corecell or glass over corecell if you want to reduce cost somewhat. I would never leave a lightweight timber boat on a mooring.

A hull like this is suitable for flatpack construction so all panels could be laser cut.

The boat ended up 8m long with maximum beam of 1.1m at a displacement of 280kg. The dimensions you initially provided are not too far off this.

The basis of the power level is your 250W applied at 70% efficiency. This efficiency is what can be achieved with modern sculling set up using CF oars etc.

You could expect a little under 6kts at 250W efficiently applied.

This power level is the sort of output that requires regular training to maintain it.

I have also attached a 3D render of a similar shape hull that I did preliminary design for pedal power. If you are considering a recreational boat for touring around then I think pedal power offers a lot of advantages. It is more efficient than rowing. You face forward so you do not get a sore neck. It can reverse easily. It will turn better. You can sprint to impressive speeds. The particular boat is a bit narrower and has ballasted keel for self-righting. It is also fully enclosed if need be.

Rick W

Originally Posted by apex1

That is the pure nonsense
Keep your mouth shut as long as the adults discuss a matter!

Regards
Richard

For real? Sorry, but you are simply DEAD WRONG and one rude mother, to boot. Epoxy inside and out is a plastic bag, one scratch and you have a plastic bag with a hole with whatever type of wood you tried to save money on, whereas a boat built like I describe is built for a lifetime. If one wants to build an epoxy boat, build it - but why use the wood for the form? By the way, the "chosen designer" has more knowledge than you´ll ever have and builds a damn fine product- I just don´t happen to agree with the choice of cladding 6mm with glass and epoxy to have a fast boat. The poster had not yet postulated that the craft would be wet year´round when I posted and I´m now not convinced anything meets all requisits. Also, I live in the land of stitch and glue glass/epoxy-sheathed Tolman skiffs. I see more rot there than you can imagine - you with your bit of "sandwich knowledge". Is it the plywood that is the "inner layer of the sandwich where the outer layer carries the load mainly" or the "...sheathed inside...for the matter of strength" that is the critical factor? Do you have ANY idea where you are going with this? Did you not hear that he wanted it to be fast? How much weight do you suppose cladding this thing is going to add? Decks and all, 6mm, glass fabric, epoxy, you say fairing compound - this thing is going to be a tank! Sandwich construction is another thing and has its place - with a lightweight core perhaps for a fast (but not practical day to day) boat or more heavily done for taking bumps and bruises of beaching or working but NOT HERE. Sorry apex, ol´boy but I don´t believe you are qualified to give "professional solutions". And with your tone, you would do well to just keep YOUR mouth shut. "Regards" - Mark

[arsinoe]

Originally Posted by rasorinc

How about something like this for under $5,000.00 US
https://www.boatdesigns.com/products.asp?dept=190

It's a nice-looking boat, but I think I need something a little longer.

Originally Posted by Rick Willoughby

I would never leave a lightweight timber boat on a mooring.

Funnily enough, the designer I talked to said that a lightweight timber boat with glass cladding would actually last longer than a boat with a fiber/core/fiber hull under these conditions. He said that any dents which compromised the wood could simply be left to dry and then filled up and painted over, after which the strength of the hull wouldn't be reduced. In the case of carbon or glass fiber, on the other hand, any dents would reduce the boat's strength. The lower weight of a fiber hull is tempting, of course, but price is an issue.

By the way, the buoy that the boat would be tied up to is in the river current about 30 feet from the bank, and there are no other buoys next to it (only ahead and astern). In other words, my boat would not constantly be knocking against a dock or another boat.

Originally Posted by Rick Willoughby

You could expect a little under 6kts at 250W efficiently applied.

This information is extremely helpful - thanks!

Originally Posted by Rick Willoughby

I think pedal power offers a lot of advantages.

So it does. But the thing is that I love rowing. Love it.

Thanks again to all for your input.

[Guest625101138]

Originally Posted by arsinoe

......


Funnily enough, the designer I talked to said that a lightweight timber boat with glass cladding would actually last longer than a boat with a fiber/core/fiber hull under these conditions. ........

I would like to the evidence he bases this on. I have seen a number of examples of soggy timber inside glass hulls. Yet to see similar failure in a foam plastic core.

Rick W

[TeddyDiver]

Originally Posted by mark775

Epoxy inside and out is a plastic bag

please http://www.westsystem.com/ss/ read some info...

Originally Posted by mark775

For real?

For real! to say more is´nt worth.

[RHP]

Sounds to me like you'd like the atlantic rowing race boats designed by Phil Morrison. You can get one of the earlier ply designs for around GBP10,000 and either keep it as it is or lob off the fore and aft accomodation and run it as a bare hull. The exchange rate is certainly in your favour at the moment as well as nearly all the boats are priced in Pounds.

Look at these links:
http://www.oceanrowing.com/Sale/index.htm
http://www.woodvale-challenge.com/Bo...+Sale+and+Rent

They're great sites in their own right and might get you into something you may regret........

[arsinoe]

Originally Posted by RHP

Sounds to me like you'd like the atlantic rowing race boats designed by Phil Morrison. You can get one of the earlier ply designs for around GBP10,000 and either keep it as it is or lob off the fore and aft accomodation and run it as a bare hull. The exchange rate is certainly in your favour at the moment as well as nearly all the boats are priced in Pounds.

Look at these links:
http://www.oceanrowing.com/Sale/index.htm
http://www.woodvale-challenge.com/Bo...+Sale+and+Rent

They're great sites in their own right and might get you into something you may regret........

Oh, I've been snooping around oceanrowing.com for years now. It's a fascinating pastime, but I definitely would regret it if I got into it myself.

As for buying that kind of a boat, it seems to me that, by the time I imported it and had all the necessary changes made, I'd still have something that, though a bit cheaper, wouldn't be optimal for my purposes. If I'm going to part with a fair bit of cash anyway, I'd rather get it done right.

But thanks for the heads-up.

TeddyDiver, Thanks for your opinion, polite and informative. I happen to use SystemThree but have quite a bit of experience with both and have read all that the manufacturers have put out. Like I said before, if it´s going to get knocked around a bit, encapsulating ply with epoxy is not my cup of tea but to each their own (at least its better than poly on ply, which is not hard to be). If I was going to do it, bearing in mind that the skins were doing most of the work, I´d do a pretty heavy satin weave skin, or better yet two 4oz. layers of s-glass, being careful not to allow pooling of resin and working absolutely as neat as possible with veil tape over seams. Foam would make a better core for this as its use is in understanding that the skins are the strength in this type of build and saves the weight of the plys and glue (admittedly, okoume is light and stiff but IMO not rot resistant enough and sapelle is great stuff!) For a short-lived boat of this type, okoume would be an option but bump the buoy and well...anything with any voids is out of the question, as well, hence the importation of British Standard 1088. In short, if one is going to encapsulate plywood, do it well, and the finished product is going to be heavier than it needs to be.

[Guest62110524]

i built boats most of my life, never got rich
What you need to say to your guy is, give me hours estimate, and hourly rate, plus detail materials
I built a lot of boats this way, hourly rate plus materials, it was a trust situation
you would(unhappily ) pay your tooth doc 400 an hr, your lawyer the same, your accountant 200,
so your boatbuilder who spent his WHOLE life learning, the trade, gets 50
In my case 100k of machines
wait til some useless lawyer want a boat, will bill him by the minute!! tee hee
A tennis or golfer get millions!! where is the sanity

[Guest625101138]

Originally Posted by whoosh

i built boats most of my life, never got rich
What you need to say to your guy is, give me hours estimate, and hourly rate, plus detail materials
I built a lot of boats this way, hourly rate plus materials, it was a trust situation
....

One part of our country has a well-tested formula for multi-million dollar contracts based on "Target Estimate".

You start with a reasonable but incomplete engineering specification and an open book approach to materials, labour and profit margin. As the scope is refined the target estimate is reviewed. Once the scope is firm the target estimate is locked in and the principal pays what it costs if the cost exceeds the target. If the cost is under the target then the contractor and principal share the difference.

This method of contract reduces legal costs and removes the contractor's risk so does not need to be factored in. It also provides incentive for the contractor to save money. It requires a savvy principal and both parties to act with integrity. If these conditions exist then it is the best form of contract I have seen in the way it delivers win-win outcomes.

I have seen situations where the scope is not firm up until 60% of the work has been done and it still works well. It does happen that there is an agreement to revise the target based on recognised scope change. By this time the principal may have already recognised value the contractor has added to cost savings and some bonus payment acknowledge.

Rick W

Originally Posted by Rick Willoughby

One part of our country has a well-tested formula for multi-million dollar contracts based on "Target Estimate".

I have seen in the way it delivers win-win outcomes.

Rick W

A fair contract, wich is in use by some of the global players in our business, like Lürssen and A&R, some Dutch do it a similar way.
The problem is, the average buyer of small craft is used with fixed prices for a boat. He does not understand the complexity of a custom built.
The widespread manhour / material contract has a disadvantage for the customer, it is easy for the yard to squeeze out more hours than necessary.
The way you recommend is the better although hard to achieve.
Regards
Richard

[TeddyDiver]

Originally Posted by mark775

I´d do a pretty heavy satin weave skin, or better yet two 4oz. layers of s-glass.

Sorry but what's it in g/sqm?
Anyways the outer skin should allways be strong enough to cope occasional scratches among other things.