Cruising Yacht performance advantage

[geem]

Sat here in Falmouth Harbour Antigua, the racing yachts are beginning to arrive ready for the Caribbean 600 race later this month. We have a VOR70 anchored next to us. A VOR65 the other side and the 100ft maxi Comanche is on the dock. She has the 24hr record for a monohull. These 3 designs are clearly up there as some of the fastest monohulls afloat. They all share some notable design features. They have wide transoms and their masts are very far aft. Clearly these stripped out carbon machines share little with any cruising monohull so why do modern cruising monohulls have their masts so far forward if the best and fastest racing boats have theirs so far back? The Imoca 60s also share this aft mast arrangement and run headsails on furlers but that's where the similarity with a modern cruising boat ends. Thoughts?

 

[wombat88]

This is/was an excellent boat if a little odd to the eye.

SailboatData.com - FJORD 28 CS Sailboat

Fjord 28 Motor Sailer. anyone sailed one?

 

[Minerva]

Sat here in Falmouth Harbour Antigua,

Firstly - you lucky bugger!

The Imoca 60s also share this aft mast arrangement and run headsails on furlers but that's where the similarity with a modern cruising boat ends. Thoughts?

Secondly I have thought for a while that the three headsails, on furlers would be a good set up for a cruising boat - a large light weight ghoster up front, a 100% or so general purpose jib and then a number 3 on inner furler for when you need to bash upwind into a blow.

A bit extra expense, sure, but the ability to change gears quickly and have nice tight, well shaped sails without the bagginess would be great. I'm saying that as someone with a new foresail with padded luff too.

 

[geem]

Firstly - you lucky bugger!
We originally planned to sail back to the Caribbean last year having sailed home when Covid hit. In September the Caribbean was in lockdown so we made a decision to stay in Portugal and apply for residency. The Portuguese residency process turned out to be a total and utter fiasco so we decided to head for the Caribbean after all. Things opened up. We arrived 2nd Jan. Great to be back.
The funny thing is we got our Portuguese residency after all?. Best of both worlds. Will cruise Azores next summer

 

[flaming]

Sat here in Falmouth Harbour Antigua, the racing yachts are beginning to arrive ready for the Caribbean 600 race later this month. We have a VOR70 anchored next to us. A VOR65 the other side and the 100ft maxi Comanche is on the dock. She has the 24hr record for a monohull. These 3 designs are clearly up there as some of the fastest monohulls afloat. They all share some notable design features. They have wide transoms and their masts are very far aft. Clearly these stripped out carbon machines share little with any cruising monohull so why do modern cruising monohulls have their masts so far forward if the best and fastest racing boats have theirs so far back? The Imoca 60s also share this aft mast arrangement and run headsails on furlers but that's where the similarity with a modern cruising boat ends. Thoughts?

Backstays, in a word.

The boats you are referencing all have square top mains and split topmast backstays. So require the crew to swap the tension from one backstay to the other when tacking or gybing. (Think running backstays, but to the top of the mast)
The advantage of this is that you can then have the boom at, or even overhanging, the transom as it does not have to clear a fixed backstay. The addition of the square top also allows you to keep a similar area for a shorter foot. These 2 things together allow you to set the mast well back in the boat without reducing mainsail size, with the associated advantages of being able to set multiple, massive, headsails.
A lot of performance sailing boats are following this trend, to greater or lesser extents. Even boats with fixed backstays have been inching the mast aft as the advantages of multiple headsails are becoming ever more apparent.
This has in fact happened in cruising boats to, most notably the POGO type. Pogo either have no backstay or offer twin backstays to provide additional security, especially when using masthead kites.

It is also worth mentioning that the biggest gains in these sorts of rigs are seen reaching when coupled with their big bowsprits they are able to set up to 3 headsails simultaneously, when using outriggers or whisker poles set to leeward This isn't really a rig that is especially well suited to a cruising boat, as you have to be quite careful with your trim to ensure that they all work together, rather than disrupt the airflow and slow you down. It's not really a set and forget sailplan. It;s notable for instance that the IMOCAs aren't really going for 3 headsails, but staying with 2. And it also works best on boats which are fast enough to drag the apparent forward significantly. Plus of course you need to be messing about with outriggers, outboard leads for the sheets etc.
And... It's a sailplan that increases in utility as you go up in size and can increase the physical separation between the sails.

So for a more conventional displacement cruiser the disadvantages, namely the hassle of swapping backstays, the added complication of outriggers etc, the necessity of a big fixed bowsprit, plus dealing with squaretop mainsails aren't really compensated by the advantage of useable extra horsepower off the wind.

 

[Stingo]

The further aft your mast is, the smaller your saloon becomes, because of the supporting bulkhead

 

[LittleSister]

This is/was an excellent boat if a little odd to the eye.

SailboatData.com - FJORD 28 CS Sailboat

Fjord 28 Motor Sailer. anyone sailed one?

I've never sailed a Fjord 28 CS, but have a copy of a review. It said its relatively oversized foresail needed big winches and quite a bit of work to control. It sailed better and faster upwind than the other motor-sailer (broadly defined) types in the same group test, but was slow downwind. (The looks and internal layout very much divided opinion.)

I guess by comparison a full-crewed racing boat can fly huge spinnakers etc. that wouldn't be practical/desirable for most short-handed cruisers, upwind speed is super important and the loads and handling of the big upwind foresail is what you have the racing crew and kit for.

Quite a few cruising cats (used to?) have their masts well aft. I can't remember the logic for that, and don't know how owners find that.

 

[geem]

Backstays, in a word.

The boats you are referencing all have square top mains and split topmast backstays. So require the crew to swap the tension from one backstay to the other when tacking or gybing. (Think running backstays, but to the top of the mast)
The advantage of this is that you can then have the boom at, or even overhanging, the transom as it does not have to clear a fixed backstay. The addition of the square top also allows you to keep a similar area for a shorter foot. These 2 things together allow you to set the mast well back in the boat without reducing mainsail size, with the associated advantages of being able to set multiple, massive, headsails.
A lot of performance sailing boats are following this trend, to greater or lesser extents. Even boats with fixed backstays have been inching the mast aft as the advantages of multiple headsails are becoming ever more apparent.
This has in fact happened in cruising boats to, most notably the POGO type. Pogo either have no backstay or offer twin backstays to provide additional security, especially when using masthead kites.

It is also worth mentioning that the biggest gains in these sorts of rigs are seen reaching when coupled with their big bowsprits they are able to set up to 3 headsails simultaneously, when using outriggers or whisker poles set to leeward This isn't really a rig that is especially well suited to a cruising boat, as you have to be quite careful with your trim to ensure that they all work together, rather than disrupt the airflow and slow you down. It's not really a set and forget sailplan. It;s notable for instance that the IMOCAs aren't really going for 3 headsails, but staying with 2. And it also works best on boats which are fast enough to drag the apparent forward significantly. Plus of course you need to be messing about with outriggers, outboard leads for the sheets etc.
And... It's a sailplan that increases in utility as you go up in size and can increase the physical separation between the sails.

So for a more conventional displacement cruiser the disadvantages, namely the hassle of swapping backstays, the added complication of outriggers etc, the necessity of a big fixed bowsprit, plus dealing with squaretop mainsails aren't really compensated by the advantage of useable extra horsepower off the wind.

That photo looks like Skorpios. She is on the entry list for the Caribbean 600. Looking forward to watching the start

 

[flaming]

That photo looks like Skorpios. She is on the entry list for the Caribbean 600. Looking forward to watching the start

It is.

 

[anoccasionalyachtsman]

As well as @flaming's explanation of rig development, a slimmer hull with planing aft sections has its centre of lateral resistance further back, and the keel and rig to move with it.

 

[dunedin]

The further aft your mast is, the smaller your saloon becomes, because of the supporting bulkhead

Don’t think so. Huge number of boats either have keel stepped masts or a strut / pole supporting a deck stepped mast - no need to be aligned with a bulkhead. Our mast is certainly abaft the bulkhead.

 

[dunedin]

Quite a few cruising cats (used to?) have their masts well aft. I can't remember the logic for that, and don't know how owners find that.

I believe that was intended to reduce the risk of pitchpoling.

 

[TLouth7]

I would contend that the main difference is not that the rig is far back, but that the back of the boat has been sawn off. If you took a conventional rig and moved the mast backwards the angle of the forestay would change (which is a feature of traditional mast-aft rigs). IMOCAs and similar have forestay angles which are pretty close to those of conventional yachts and the ratio of main to foretriangle size is also within a conventional range.

The difference is that the masts are massively tall for the LOA of the boats. If you left the mast in the conventional position and increased its height then the forestay would be very steep. So you move the mast back to maintain that angle, and your backstay becomes steeper instead. Flaming has already described how they deal with that.

If you took a TP52 (I realise that is not exactly a conventional cruiser) and cut the last 20% off the back of it you would have a boat that looked very much like an IMOCA. The mast would be more than 50% aft without changing the rig in any way.

 

[Sandy]

Comanche

I am not sure I'd describe that particular vessel as a cruising yacht.

 

[flaming]

I would contend that the main difference is not that the rig is far back, but that the back of the boat has been sawn off. If you took a conventional rig and moved the mast backwards the angle of the forestay would change (which is a feature of traditional mast-aft rigs). IMOCAs and similar have forestay angles which are pretty close to those of conventional yachts and the ratio of main to foretriangle size is also within a conventional range.

The difference is that the masts are massively tall for the LOA of the boats. If you left the mast in the conventional position and increased its height then the forestay would be very steep. So you move the mast back to maintain that angle, and your backstay becomes steeper instead. Flaming has already described how they deal with that.

If you took a TP52 (I realise that is not exactly a conventional cruiser) and cut the last 20% off the back of it you would have a boat that looked very much like an IMOCA. The mast would be more than 50% aft without changing the rig in any way.

Not sure I agree with that. Forestay angle looks a lot less on the latest boats than this 37 foot IOR design for example. And it's mast is very tall for the length of boat.

 

[westernman]

The further aft your mast is, the smaller your saloon becomes, because of the supporting bulkhead

The bulkhead does not have to be where the mast is. This is why in some cruising boats such as the pogos, the mast is in the middle of the saloon.

 

[Bobc]

BACK OF THE BUS.......NOW!!!!

 

[geem]

I am not sure I'd describe that particular vessel as a cruising yacht.

I didnt

 

[anoccasionalyachtsman]

I believe that was intended to reduce the risk of pitchpoling.

The fore and aft location makes no difference in that sense.

 

[geem]

I would contend that the main difference is not that the rig is far back, but that the back of the boat has been sawn off. If you took a conventional rig and moved the mast backwards the angle of the forestay would change (which is a feature of traditional mast-aft rigs). IMOCAs and similar have forestay angles which are pretty close to those of conventional yachts and the ratio of main to foretriangle size is also within a conventional range.

The difference is that the masts are massively tall for the LOA of the boats. If you left the mast in the conventional position and increased its height then the forestay would be very steep. So you move the mast back to maintain that angle, and your backstay becomes steeper instead. Flaming has already described how they deal with that.

If you took a TP52 (I realise that is not exactly a conventional cruiser) and cut the last 20% off the back of it you would have a boat that looked very much like an IMOCA. The mast would be more than 50% aft without changing the rig in any way.

I don't see it like that. On the VOR70 below (anchored next to me) the boom looks quite short. The distance from the back of the boom to the transom quite generous. By comparison the Ben 57 behind us appears to have a steep forestay angle compared to the VOR70. The mast on the VOR70 appears to be more than 50% towards the rear of the hull.