When is heavy too heavy ? (Strange boat problems)

[TiPegleg]

Hey all, so I’ve been visiting boats with the intention to buy in the next few months. My focus has been French aluminum and steel center boarders and considering their rarity, I’ve been getting around! So here’s my issue:

I found a really great 42ft caroff/strong al built boat that’s amazingly built in galvanized steel. I did a survey, Everything looks great, very excited etc. but then the owner tells me the tonnage - 18t on a LOA 42ft and a LWL of ~36!

Now I’ve sailed some very heavy metal boats before, a 34t 52ft Bruce roberts in particular, so I know that weight isn’t everything. So I asked for the sail plan and that’s where I needed to ask the forum (first time posting!). The sail area (main+100% jib) = 635sqft... main and 130% genny = 930 sqft... this basically gives me a SA/D of ~10-14... pretty sure this is motor sailer territory, yeah?

Now keep in mind, the owner has the boat fully up to cruising trim, including 200gal of diesel and 100gal of water, 6 big ol AGMs, etc. The dink is in davits and the food stores are full. If I ignore the owner’s tonnage and go by the design spec, we’re talking about 14t, which changes the math considerably and put the whole thing more in line with a “heavy cruiser”. That said, I’d still expect a sail plan over 1000sqft for this boat.

Finally, one other oddity... this boat has a 110hp 6 cylinder diesel swinging a 23” prop on an oil sealed shaft... just absolutely massive...

If this boat was set up from the ground up as a motor sailer this is the first ever metal center boarder I’ve seen this way. The boat also has all the gear for a spinnaker and actually has a big asym... why would you spec a spinnaker for a motor sailer?? All of the winches on board are sized appropriately for a larger rig than the spec sheets and plans given to me by the owner show. Oh, and the mast- beefy doesn’t convey. Double spreaders, split back stay, double head stay, baby stays, and removable inner forestay... for 600-950sqft?? Very confusing.

So my question(s):
1) when using the usual calculators and metrics should I use 18t (cruising tonnage?) or 14t (design tonnage)?
2) how heavy is too heavy? I’m not looking for a motor sailer. Is this a motorsailer? Do motorsailers ever have spinnaker poles etc?
3) when using a SA/D calculator I always used 100% foretriangle + main but I read in Eric Spondberg’s excellent pdf about design ratios that you should use the “upwind area” in which case I’d be using the 130% genny area?

I’d really like to make an offer on this boat, but was stopped dead by all of this. I can’t do a motorsailer with my plans so if that’s what I’m dealing with... anyway, thanks for any help/opinions/advice!

[Celestialsailor]

I will just say welcome to the forum. I had build 2 steel sailboats of my own and helped a friend on another. Today, I'm not a big fan of steel. I am strictly f/g now and for some of the issues you mentioned. I wouldn't worry so much about analyzing the numbers as much as just going with something that requires less maintenance down the road, is constructed out of a proven material and can sail out of it's own way.

[Rucksta]

How does it sail?

SA/D has a bigger impact on acceleration and light air performance than it does for top speed which is governed by water line length.

For passage making I reduce sail on my race boat to 15 and make hull speed or better from 10kts true.

The big steely sounds like a practical cruising boat

[GILow]

Interesting coincidence. My 42 foot Swanson was at least 17 tons when we bought her. Well over her correct weight, which should have been in the 12 to 14 ton range.

She was not a motor sailor at that weight, but there is no doubt that her performance was far from exciting. 50 foot mast, cutter rigged sloop, and normal speeds were in the 5 to 6 knot range.

Roll the clock forward, I did a complete refit and now she’s 14 tons and a very much nicer boat to sail. Normal speeds are now in the 6 to 7 knot range, motion is more lively but still smooth. (She used to have a somewhat “oily” motion, if that makes sense?)

Based on my experience, I think you’d find a boat of that weight and size combo a little underwhelming. And, I’m guessing, you won’t be able to put it on a diet like I did for my boat.

[Cheechako]

Keep in mind that any of the big fiberglass boats with a lot of Teak and etc weigh way beyond their specs, especially the Asian built ones.
Intended use matters. For occasional cruising etc I'd not want a real heavy boat.
For the Trade Winds I wouldn't mind. But for local use a very heavy boat will just end up a motor boat...

[Nicholson58]

Where do you plan to sail?

Lots of wind always in the Caribbean. We rarely run the 130 Genoa. We are 58 feet, 40 tons. We made the Hampton, Va to BVI in 7.5 days, favorable winds.

[TiPegleg]

Good stuff so far, intended use is long distance and all over. This boat is for long term cruising in possibly inhospitable locations.

The boat is on the hard so no way to do a sea trial and the owner (second owner) is a first time boat owner. I’d love to talk to the original owner/buyer but I don’t have any contact info.

Oh to add to the weight equation, there’s 250ft of 3/8” B chain in the bow... all just incredibly beefy.

Any consensus on questions 1 or 3?

[BillKny]

Are you sure the "tonnage" you are being quoted is the actual displacement of the vessel?

The Net and Gross tonnage as recorded on the documentation paperwork have very little to do with the actual weight of the boat. I say this because a registered Net Tonnage of 18 or so wouldn't be totally out of line for a boat of this size, and is a measure of its VOLUME not its weight.

[TiPegleg]

Originally Posted by BillKny

Are you sure the "tonnage" you are being quoted is the actual displacement of the vessel?

The Net and Gross tonnage as recorded on the documentation paperwork have very little to do with the actual weight of the boat. I say this because a registered Net Tonnage of 18 or so wouldn't be totally out of line for a boat of this size, and is a measure of its VOLUME not its weight.

Nope, not really absolutely certain of much with this boat, unfortunately. The 18t figure comes from when the boat was in a travel lift and was weighed prior to being put on the hard. The plans I have seen state a displacement of 14t but the plans were also *based* on an aluminum boat and then executed in steel. I’m still trying to get more info from the owner who I hope has contacted the original owner. It almost looks like the sails are smaller than the plan for the aluminum equivalent, which makes no sense

[JPA Cate]

Hello TiPegleg, and welcome aboard CF, land and sea opinion central.....

1) when using the usual calculators and metrics should I use 18t (cruising tonnage?) or 14t (design tonnage)?
Use the cruising tonnnage. All the tools and spares are heavy. And so is the food and water.

2) how heavy is too heavy? I’m not looking for a motor sailer. Is this a motorsailer? Do motorsailers ever have spinnaker poles etc?

If you really want to sail a very heavy boat, you need to have light air sails of good quality. If the boat, at sea trials, feels sluggish, you'll have your answer, and since you are so concerned, I wouldn't buy it until it had passed its sea trial to your satisfaction. I think the post above, that stated that you'd be motoring a lot due to the inconvenience of setting enough sail to get her out of her own tracks and be difficult to maneuver docking could well be the correct take on it. In this supposition, we have the reason for the disappointed first owner selling it on.

3) when using a SA/D calculator I always used 100% foretriangle + main but I read in Eric Spondberg’s excellent pdf about design ratios that you should use the “upwind area” in which case I’d be using the 130% genny area?

If you're not liking the numbers you've been getting, pay attention to what your inner sense is warning you about.

Do remember that there are lots of days on a long Pacific passage where the days winds are under 15 knots.

Ann

[skipperpete]

120hp through a 23” propeller seems to imply motor sailer...... and consequently, large fuel tanks. I do like the oil filled sterntube though, it might have been built by a commercial vessel shipyard with such substantial machinery. What is her country of origin?
I’ve never encountered a galvanized steel vessel, I wonder how that was accomplished ?
Multi chine built with galvanized steel plating and welds zinc sprayed? or hot dipped entire hull after construction are two possibilities.

[Caleb_Grey]

Originally Posted by TiPegleg

.

If this boat was set up from the ground up as a motor sailer this is the first ever metal center boarder I’ve seen this way!

S&S designed quite a few heavy metal centerboard tall rig beauties back in the day.

https://www.yachtworld.com/boats/1968/sparkman-$-stephens-custom-3556951/

200hp motor
600gal fuel
65"
77' rig
6' centerbord, actually has 2 smaller one aft
75000lbs dry
Derecktor built in aluminum

[Fore and Aft]

TiPegleg how does she sail, and how does the freeboard look? If the toe rail is close to the waterline then you may have a problem.
The sail area thing is not really an issue, a gennaker in a sock would help you out in light weather. You also have to realise that there is more to sailing than just a good yacht, your ability has a lot to do with how well she will sail as well.
The engine issue does not surprise me, I have surveyed other 40 footers with 100+hp motors. One owner got such a good deal he could not turn it down, I think it was a display model that they needed to move on. Another owner owner just liked a big motor.
This boat owner sounds like you a bit, I think you will find you have both read way much into everything. I would say the current owner thinks every sail has potential to turn into a hurricane so he has way oversized everything. Now you have come along with another mindset and are worrying about everything being oversized and quoting some designers sail ratios. I can tell you now, every yacht designer has their own philosophy when it comes to ratios, displacement etc.
If she sails well, ticks all your boxes and you like her looks then why not buy her? Worst comes to worst you can always sell her again.
Cheers

[Wckoek]

Starting from 12 tonnes berthing will become more difficult, many would like to have bow thruster on anything more than 15 tonnes.
I would think 20 tonnes would be too much a boat for a person in terms of sail area, you need more than 1200 sq ft of sail to have decent performance, unless we are talking about motorsailor or trawler.

[Jim Cate]

So my question(s):
1) when using the usual calculators and metrics should I use 18t (cruising tonnage?) or 14t (design tonnage)?
2) how heavy is too heavy? I’m not looking for a motor sailer. Is this a motorsailer? Do motorsailers ever have spinnaker poles etc?
3) when using a SA/D calculator I always used 100% foretriangle + main but I read in Eric Spondberg’s excellent pdf about design ratios that you should use the “upwind area” in which case I’d be using the 130% genny area?

More opinions:

1. In this case the 14 t "design" disp is in reality for a different boat (alloy hull), and has no meaning for your prospect. Thus IMO you should not base anything on ratios derived from that figure. In the real world, most boats weigh in at well over their design disp even when not fully loaded for cruising, and this makes it difficult to use the theoretical ratios and observations of similar vessels performance to forecast a specific boat's performance with any confidence.

2. The term "motorsailor" is not very specific. Sure, boats with big engines and small sail plans get tagged with it, but IMO there is no hard and fast line of demarcation involved... but I'd sure slap that label on your prospect. And of course a "motorsailor" can have spinnaker gear fitted... why not?

3. I disagree with Eric's thought on use of "upwind area" to compare boats. Considering that one can fit a genoa of 110 % on up to >150%, which one do you use when calculating? Makes the metric kinda useless IMO. Oh, do remember that Eric espouses odd designs with tiny mainsails and huge foretriangles, and he likely wants his designs to have good numbers in the eyes of potential customers.

All that aside, my expectation is that your prospect will not sail well in anything short of a fresh breeze... perhaps 15 kts apparent, likely even more. This opinion is based on the numbers presented, the huge propellor and the (only imagined) hull shape typical of vessels of this type. To me, this is a bad outlook for a serious cruising boat, for in reality light airs are far more common in the usual cruising grounds than are stronger winds. I know that some folks don't care to sail in light winds, and are fond of saying "I'm cruising, and I don't care how long it takes to get somewhere", but that sure doesn't work for me.

The combination of an odd design and no sea trial possible would for me rule the boat out of consideration, but YMMV. Good luck with your search and your decision.

Jim