Sloop to Ketch conversion

[SailorBOI]

There does not appear to be much online about this, especially what matters below the waterline. I'm in the market for a 45' to 60' ketch but there is not much I'd consider truly worthy of ocean passages. However, some sloops in this range may convert to ketch fairly easily if I could find out what keel and rudder shape and configuration is required to accommodate the above-water-line changes. Does anyone have any specifics on what to look for, or even some examples? I know Passport/Petersens did ketch and sloop rig on the same hulls for a number of years and there are other examples. However, I'd like to be able to look at the shape of a sloop hull and determine if it could be converted to ketch before then considering any challenges above the waterline. This would increase the likelihood of finding a suitable "bluewater" ketch for my family. Thanks in advance for any wisdoms or perspective on this.

[MyCatLife]

My first thought... (snarky and somewhat in jest... please forgive me, and hopefully chuckle)... Have you been drinking?

I think this is a much bigger task than you appreciate... and sounds prohibitively expensive.

But... if you pursue,... PLEASE PLEASE PLEASE create a thread so I can follow the progress.

[NevilleCat]

First thoughts would be you would be moving the main mast forward so unlikely to have a bulkhead there to deck step it, so new compression post and or keel step and new chainplate positions for two masts.
The underwater shape is probably the least of the issues but I imagine the longer the keel the better if you aren't sure of your centre of effort calculations.

[boatman61]

You'd find it easier to convert a sloop to a yawl.

[tkeithlu]

My impression is that you have been frustrated by what you see on the market in ketches ansd have started toying with conversion of a sloop, as a way out of beating your head on a wall trying to find that wonderful blue water ketch.

I and, others above, encourage you to keep looking. The conversion of an existing sloop involves so many expensive changes, followed by the risk that it won't really work well when you finish, as to make it a bad idea.

[SailorBOI]

Originally Posted by MyCatLife

My first thought... (snarky and somewhat in jest... please forgive me, and hopefully chuckle)... Have you been drinking?

I think this is a much bigger task than you appreciate... and sounds prohibitively expensive.

But... if you pursue,... PLEASE PLEASE PLEASE create a thread so I can follow the progress.

I understand your response as most would think, if anything, a ketch to sloop conversion would be the order of the day. However, I think it more likely that those who expect to feel just as well rested on an ocean passage in a sloop that dances over every wave rather than enjoying the zzz's that come with a steady well-balanced ketch have perhaps been doing more drinking than thinking.
I do wonder how many of us have actually enjoyed the sleep they get on a well-balanced ketch on an ocean passage. I feel fortunate that I have.... and then stepped aboard a sloop for a two day passage - couldn't sleep very well at all no matter which bunk I migrated to.

As for the rig conversion.... I do see some sloops that I think might suit a ketch conversion that are approaching or have come due to have their standing rig replaced anyway (sufficiently reflected in the asking price most of the time), so I figure... why not expand my search to such suitable hulls?

[SailorBOI]

Originally Posted by NevilleCat

First thoughts would be you would be moving the main mast forward so unlikely to have a bulkhead there to deck step it, so new compression post and or keel step and new chainplate positions for two masts.
The underwater shape is probably the least of the issues but I imagine the longer the keel the better if you aren't sure of your centre of effort calculations.

Indeed, I'm only aware of a very few hulls built purposely with two such bulkheads close together to allow the mast to have two positions without modifications such as adding a compression post. I was really just hoping to expand my list of possible sloops to consider if I found one I could bargain down based on the state of the rigging. Adding and changing chain plate positions is another hurdle which does not always go to plan either, but I weigh this option up against having to travel overseas to inspect and purchase an already-ketch as there is really not much in the $100k-$250k price range here in AUS/NZ. Not keen to travel even if the pandemic ended tomorrow. So it's ketch conversion vs. I hate flying conundrum for me. Joy.

[El Pinguino]

I can't imagine why you would do it.
My boat, 39 foot Westerly Sealord could be ordered as either a sloop or a ketch. They built 42 of them , only one or maybe 2 were completed as ketches.
All the hulls have a plinth for mounting the mizzen on. Boom would be slightly shorter and mainsail slightly smaller.
Sail area info here along with a rather nice photo of my boat
https://wiki.westerly-owners.co.uk/i...tle=Sealord_39

[Benz]

The seakindly-ness of the sloop vs ketch might have more to do with hull shape than rig. It's the hull, after all, that's cleaving the water and getting tossed around.
I can't argue against a split sail plan being easier to trim for easy steering--my favorite is the schooner--and the best, easiest ride I ever had was in a 38' schooner with a full keel, which tracked well and steered light. Predictably, the squirreliest ride ever was in a Santa Cruz 70: a fin keel/spade rudder job that pounded like the devil and required endless helming.
Given the structural difficulties in converting a rig, especially on something that big, you might be better off saving up for an Amel, which I believe still has a ketch in production.
If you're on a budget, one of the Formosa-like leaky teakys that requires a ton of structural repair anyway might be found relatively cheap. Some of them were ketches to begin with.

[SailorBOI]

Originally Posted by tkeithlu

My impression is that you have been frustrated by what you see on the market in ketches ansd have started toying with conversion of a sloop, as a way out of beating your head on a wall trying to find that wonderful blue water ketch.

I and, others above, encourage you to keep looking. The conversion of an existing sloop involves so many expensive changes, followed by the risk that it won't really work well when you finish, as to make it a bad idea.

Spot on. As for the risk, being an analyst I would be calculating the hell out of it on top of knowing in advance that the same hull design has been built and rigged as a ketch before. That and what NevilleCat said about being a long keel. Can't beat a long keel ketch (D/L around 320) for comfort on ocean passages.

[SailorBOI]

Originally Posted by boatman61

You'd find it easier to convert a sloop to a yawl.

Thanks for mentioning this. I've been meaning to ask if, with the rudder post being forward of the mizzen.... can you actually steer a yawl via the mizzen sail if the rudder broke? I had to do this at 2am on a ketch in the Tasman once and was surprised and how effective it was. But on a yawl?

[SailorBOI]

Originally Posted by Benz

The seakindly-ness of the sloop vs ketch might have more to do with hull shape than rig. It's the hull, after all, that's cleaving the water and getting tossed around.
I can't argue against a split sail plan being easier to trim for easy steering--my favorite is the schooner--and the best, easiest ride I ever had was in a 38' schooner with a full keel, which tracked well and steered light. Predictably, the squirreliest ride ever was in a Santa Cruz 70: a fin keel/spade rudder job that pounded like the devil and required endless helming.
Given the structural difficulties in converting a rig, especially on something that big, you might be better off saving up for an Amel, which I believe still has a ketch in production.
If you're on a budget, one of the Formosa-like leaky teakys that requires a ton of structural repair anyway might be found relatively cheap. Some of them were ketches to begin with.

And that is the core of the matter when it comes to my perception of comfort on ocean passages. The closest I've ever heard anyone come to qualifying a claim that the rig, not just the hull, determines "seakindly-ness" is something about "...how the power from the lower, broader sail plan transmits to the lower(?) centre of mass". But I've not seen or heard anyone really analyse the physics of the rig-and-hull combination to back up the claims that I and others perceive as 'better comfort on a ketch'.
It certainly seems that 20 years ago, you could get a good ketch for the budget I have but now, I must save many times that for a new ketch or adopt a potential maintenance nightmare.

[SailorBOI]

Originally Posted by El Pinguino

I can't imagine why you would do it.
My boat, 39 foot Westerly Sealord could be ordered as either a sloop or a ketch. They built 42 of them , only one or maybe 2 were completed as ketches.
All the hulls have a plinth for mounting the mizzen on. Boom would be slightly shorter and mainsail slightly smaller.
Sail area info here along with a rather nice photo of my boat
https://wiki.westerly-owners.co.uk/i...tle=Sealord_39

Thanks - I have noticed some sloops have such plinths but can't be sure if they were forward or aft of the rudder. I guess I'm still hoping someone has a list of hulls with specs that show where and what bulkhead positions are available, plinths for mizzens, chain plate positions etc to accommodate whatever rigs are desired. I'm guessing the list is small as most manufacturers would make this choice for the buyers based on market demand.

[boatman61]

Originally Posted by SailorBOI

Thanks for mentioning this. I've been meaning to ask if, with the rudder post being forward of the mizzen.... can you actually steer a yawl via the mizzen sail if the rudder broke? I had to do this at 2am on a ketch in the Tasman once and was surprised and how effective it was. But on a yawl?

The yawl rig has like the ketch two masts, but the mizzen mast is aft of the rudder. This sail plan derived originally from commercial fishing boats. Later on, it became quite popular with single-handed sailors because sails could be trimmed to sail without having to control the rudder.

In comparison to the ketch, the mizzen sail on a yawl is less for propulsion than for balancing the rest of the rig. Nowadays, the yawl lost popularity since other steering aids like electronic autopilots or mechanical wind vanes make her mizzen sail and mizzen mast redundant.

Extract from yacht design..

[Bill O]

Originally Posted by NevilleCat

First thoughts would be you would be moving the main mast forward so unlikely to have a bulkhead there to deck step it, so new compression post and or keel step and new chainplate positions for two masts.
The underwater shape is probably the least of the issues but I imagine the longer the keel the better if you aren't sure of your centre of effort calculations.

+1. ^^^^

How good are at doing the calculations (for CE, etc.) to move the mast forward with an appropriate sized mizzen? While it can be done, why? If you really want to this would start with a copy of Skenes to look at the calculations needed.

We like our ketch rig and this rig can be appropriate for a 50-60' cruising boat. If you are just going out for day sails you may be better off w/a sloop rig.

If you can't find a boat in your area, would be easier and save a lot of experimentation to look a further distance for a factory made ketch. If you do a search on YW for a ketch in the 45-60' range, there are plenty to choose from.