KK42 as motorsailer?

[ddw36]

Can a KK42 be converted to a motorsailer? Or is it too expensive to do so? Is it something that has to be done at the build? Or can it be done at all? I do have a reason for asking.

 

[O C Diver]

While I'm not an expert on sailboats, I would guess there would be some pretty big hurdles to overcome for a KK 42 to carry meaningful sail. A keel to control side slip and substantial ballasting to offset the rolling force of wind pushing on sails to roll the boat seem to be big challenges. Changing the mast and standing rigging to handle the load of meaningful sail area, would be another.

Ted

 

[ranger58sb]

Can a KK42 be converted to a motorsailer? Or is it too expensive to do so? Is it something that has to be done at the build? Or can it be done at all? I do have a reason for asking.

i suspect a lot of work and $$$ with maybe underwhelming results... but I'm not by any stretch a NA...

What would be the goal? Would this be starting with a KK42 you already own? Or else why wouldn't a decent alternative be just shopping for a motorsailer instead?

-Chris

 

[Larry M]

The short answer is no. Trying to add a mast, sails and associated rigging would be difficult if even possible. The hull design doesn’t allow it to be driven efficiently through the water via wind. It has 15’8” beam, 39’2” water line and displaces ~40K lbs. Lena and I delivered a motor sailer from Tasmania to New Zealand. It’s hull design (I think most motor sailers are similar) was that of a sailboat but the decking/house were more power boat like and had an engine that could power the boat as fast as it could sail. With the sails up and engine running, in reasonable winds, hull speed was easy to achieve and maintain. I know of sailboats that have been converted to motor sailers but I can’t say I’ve seen a trawler converted to a one.

 

[DavidM]

There are several problems with converting a KK 42 to a motorsailer:

Motorsailers typically have much more ballast than the KK 42, typically 25+% of their displacement. The KK 42 has about 5% ballast ratio.

A motorsailer has a SA/Disp ratio of 10 or more. Putting this much sail on a KK 42 adds tremendous stresses to the mast and rigging and the supporting hull structure. You can probably get to a SA/Disp of maybe 5 at best without completely rebuilding the hull to take the loads.

And as noted above, the KK 42 has a shallow keel so it will crab sideways in any significant wind.

So a KK 42 with sails just isn't going to sail very well, maybe giving you 3 kts of speed with 15 kts of wind with no power. That is enough to stabilize and assist with the motor and maybe give you an emergency get home capability.

This article from Good Old Boat Magazine lays out the parameters. It was written by Ted Brewer, a well respected sailboat NA. https://goodoldboat.com/dissecting-the-motorsailer/

David

 

[cardude01]

There are several problems with converting a KK 42 to a motorsailer:

Motorsailers typically have much more ballast than the KK 42, typically 25+% of their displacement. The KK 42 has about 5% ballast ratio.

A motorsailer has a SA/Disp ratio of 10 or more. Putting this much sail on a KK 42 adds tremendous stresses to the mast and rigging and the supporting hull structure. You can probably get to a SA/Disp of maybe 5 at best without completely rebuilding the hull to take the loads.

And as noted above, the KK 42 has a shallow keel so it will crab sideways in any significant wind.

So a KK 42 with sails just isn't going to sail very well, maybe giving you 3 kts of speed with 15 kts of wind with no power. That is enough to stabilize and assist with the motor and maybe give you an emergency get home capability.

This article from Good Old Boat Magazine lays out the parameters. It was written by Ted Brewer, a well respected sailboat NA. https://goodoldboat.com/dissecting-the-motorsailer/

David

That’s an interesting article, and especially for me since Dorian wrecked my sail rig and now I need to decide what to go back with.

The old rig had a total of 397 square ft of sail area. 195 jib and 205 main. The furling jib was easy to use, but the in mast furling main was expensive and not very easy to deploy or or lower IMO. Had to be perfectly heading into the wind to furl it back in, and solo that was hard to do at times. I think I might go back with a regular hanked on main sail next time to save money and make it easier to lower quickly. Thoughts on that?

As for performance, my sails were only used when also under power. I did try to sail it with no engine a few times, and got about 3-5 knots in maybe 15 knots of wind. It did not point to the wind well at all without the engine. The sails did make a huge difference in stability.

The 40’ mast height and sail area was worked out by an Island Packet engineer vs the 52’ mast of the SP sail version of my boat and about 750 sq ft of sail. So I don’t think I need to go any bigger than that. My boat has a bit less ballast than the original SP sail version.

Wonder if there is anything else I should change on the sail rig now that I have the chance?

 

[dhays]

The old rig had a total of 397 square ft of sail area. 195 jib and 205 main. The furling jib was easy to use, but the in mast furling main was expensive and not very easy to deploy or or lower IMO. Had to be perfectly heading into the wind to furl it back in, and solo that was hard to do at times. I think I might go back with a regular hanked on main sail next time to save money and make it easier to lower quickly.

I've only had one boat with in-mast furling. They can be a bit temperamental to furl. A furling rig is more expensive for sure. You may want to consider a lazy jack system such as the Doyle Stackpack. Less money than a furling system and arguably easier to manage single-handed. If I was in your situation, that is what I would do. One of the reasons is that your main will have better shape and performance than a furled main.

 

[rslifkin]

That’s an interesting article, and especially for me since Dorian wrecked my sail rig and now I need to decide what to go back with.

The old rig had a total of 397 square ft of sail area. 195 jib and 205 main. The furling jib was easy to use, but the in mast furling main was expensive and not very easy to deploy or or lower IMO. Had to be perfectly heading into the wind to furl it back in, and solo that was hard to do at times. I think I might go back with a regular hanked on main sail next time to save money and make it easier to lower quickly. Thoughts on that?

As for performance, my sails were only used when also under power. I did try to sail it with no engine a few times, and got about 3-5 knots in maybe 15 knots of wind. It did not point to the wind well at all without the engine. The sails did make a huge difference in stability.

The 40’ mast height and sail area was worked out by an Island Packet engineer vs the 52’ mast of the SP sail version of my boat and about 750 sq ft of sail. So I don’t think I need to go any bigger than that. My boat has a bit less ballast than the original SP sail version.

Wonder if there is anything else I should change on the sail rig now that I have the chance?

In your case, how hard would it be to add a little more ballast and carry closer to the sail area of the SP version? Or even aim a bit closer to that sail area without more ballast and just expect that you'll need to reef earlier (but you'll gain more drive from the bigger sails in light air).

 

[cardude01]

Ahh, I didn’t realize a regular hanked on sail would offer better shape. Is that because it is connected to the full length of the boom and not just at the end?

And yes, I was considering a lazy jack system to help contain the sail.

 

[cardude01]

In your case, how hard would it be to add a little more ballast and carry closer to the sail area of the SP version? Or even aim a bit closer to that sail area without more ballast and just expect that you'll need to reef earlier (but you'll gain more drive from the bigger sails in light air).

I’m not sure how I would add more ballast in the keel, other than opening it up somehow. Don’t really want to do all that. The idea of more sail is slightly appealing, but not sure I’ll be able to get good sailing performance out of this boat. But it’s a good question to ask the rigger!

Wonder how much weight I would save using a lighter, traditional mast?

When I called the original rigger he was thinking all the stays should be replaced because of the possible strain it was all under when the mast snapped. Is that right or is he just trying to sell more parts? The entire rig is only 2 years old.

 

[koliver]

Ahh, I didn’t realize a regular hanked on sail would offer better shape. Is that because it is connected to the full length of the boom and not just at the end?

And yes, I was considering a lazy jack system to help contain the sail.

In order to hide in the mast the furling sail will have no battens, or if it has battens they must be vertical in the sail, so that alone complicates and adds weight to the furling system.
Any furling system that doesn't go in the mast can have full length battens, so the shape can be much fuller, increasing sail area significantly.
The Lazy Jack systems have improved over the years and now the ones with a big bag of sunbrella on the boom allow a big sail to drop into that bag and be zippered up single handed, without much fanfare.
I got to use one earlier this summer on the delivery trip I did on a Jeanneau 37.
In the boom furling with a power halyard winch allows much better control and reefing, furling, etc, so no issue with single handing. This feature has other benefits, as the weight of the sail is in the boom when furled and more in the boom when reefed, as opposed to in the mast, where all of that weight is up high, impacting stability.

 

[healhustler]

Regarding the motor-sail kit for a KK 42’, I think all the evidence you need to establish the practicality of the idea is stated above by Cardude. It tells a pretty good story of the cost and effectiveness of an add-on kit to a motor vessel design. Cardude’s boat (a 41’ Island Packett PY Cruiser) actually IS a sailboat design sans the sail rig, a bit of keel depth and some ballast. It was as good of a candidate as one could have for motor-sailor conversion. Performance benefits were surely good enough for get-home security and stabilization, but practicality as a powered sailor without a full size kit was minimal.

The KK 42’ would require deck mods, keel mods, reinforcement and backing plates at rigging attachments, and a darned good Naval Architect. Even then it might only yank the bones out of it. For the same money and a lot less trouble, you could have the finest 42 out there with the best of get-home pony motors.

On the other hand, if a 40’ish pilothouse motor-sailor is your style, look for a Shucker or perhaps a Willard Staysail ketch.

 

[ben2go]

To sum it up, you could could buy a motor sailer or sailboat of the same length and width for the same price or maybe less than a KK.

 

[dhays]

Ahh, I didn’t realize a regular hanked on sail would offer better shape. Is that because it is connected to the full length of the boom and not just at the end?

And yes, I was considering a lazy jack system to help contain the sail.

Keith answered your question well. In boom furling instead of in mast furling is nicer for the reasons he explained, but again they are more cost. OTOH, they do eliminate the jack lines of a lazy jack system and you don't need to zip or velcro the bag closed afterwards. I've never had a boat with in boom furling.


I will say that with my boat with in mast furling I was pretty happy with it other than the lousy sail shape. Coming from a racing background, it always bugged me.

 

[ddw36]

Thanks to all for valuable advice. For various reasons, I've focused on the KK42 as a voyager. I got the idea from also reading re: Diesel Ducks, which can come w/ a sail rig, to be used as a 'get home" system, chiefly, or to save fuel underway. No, I would not expect it to perform like a sailboat.


Why not buy a DD? I can't afford it, and other reasons not related to DDs.

 

[dhays]

Thanks to all for valuable advice. For various reasons, I've focused on the KK42 as a voyager. I got the idea from also reading re: Diesel Ducks, which can come w/ a sail rig, to be used as a 'get home" system, chiefly, or to save fuel underway. No, I would not expect it to perform like a sailboat.


Why not buy a DD? I can't afford it, and other reasons not related to DDs.

My own feeling is that if you are interested in the advantages of a motorsailor, you are probably better off buying a boat designed as such. A motorsailor can give you real fuel savings over time just by using the sails while running the engine. Maybe it only means a 1/2 knot increase in speed for a given rpm or being able to reduce rpm by 500, but it can help.



Adding a rig to a boat not designed for it will not really give you much performance increase nor give you much reasonable "get home" capability.


However, just because the idea won't work doesn't mean it was a bad idea.

 

[rsn48]

Probably the easiest and best solution is to sell your boat and purchase a motorsailor.

 

[geoleo]

Ahh, I didn’t realize a regular hanked on sail would offer better shape. Is that because it is connected to the full length of the boom and not just at the end?

And yes, I was considering a lazy jack system to help contain the sail.

I have had 4 Mackpacks which are basically same as Doyles stackpack. hey are not nearly as good as catamaran style "Lazy Bags". I advise contacting Dave Calvert of Calvert sails both for the lazybag and advise on the rig. Dave is a step above on how a boat moves thru the water. Also know there are much better fabrics for the lazy bag than Sunbrella -which chafes rather easily.

 

[fgarriso]

There used to be an old saying " Motor sailors do not sail or motor very well".

I myself was in the process of buying a 65' Lancer motor sailor until I sea trailed one. We were motoring of off Catalina at ~7 knots with the wind at our backs and the sails set. When we shutdown the engines the boat slowed to ~2 knots. Then I was told this was "normal".

I didn't buy the boat.

 

[mcarthur]

You could add a short stub-mast plus genoa and spinnaker, and just use them as down as downwind-only assistance. May work ok from stern quarter to quarter, so 90 degrees. Forget entirely about abeam or ahead. The mast then has little compression into the deck, and with backstay(s) could be reasonably light so easy to take down.

 

[lipets]

U can use a shorter mast with a square top main which will add about 20% sail area



Lazy jacks for a cruising boat is really a great alternative.

 

[AusCan]

I wouldn't recommend anyone to converting a KK42 to a motorsailer. Not because it couldn't be done; with enough time and money you could convert it to anything. Look at what Hendo has done!

If you shop around carefully there are some very good blue water motorsailers on the market.

The motor sailer I have is one of 3 built by the manufacturer, although over 150 of the same boat were built as regular displacement cruisers. The hull shape is fairly well suited to a motor sailor with its narrow canoe shaped aft end.


As Lippets mentioned, it has a square topped gaff rig with a very short mast giving me about 300 square feet of main sail and a 100 square foot self tacking jib. The small sails are easy to single hand in all but gale force winds.

Like the boat fgarriso tried out, (post#19) my motorsailer will only do about 2 knots in a 7 knot breeze, but it is fairly rare to have days that calm around here. Of course with smaller sails, they won't propel a cruising boat as fast as a lightweight racing sailboat, but I don't see why adding sails make it a poor power boat.

 

[geoleo]

Square Rig is only solution.

 

[Sangraal]

Can a KK42 be converted to a motorsailer? Or is it too expensive to do so? Is it something that has to be done at the build? Or can it be done at all? I do have a reason for asking.

KK made 8 passagemaker trawlers which are sail assist. I own one of them. The sails assist but they are really a stability and range extender allowing hull speed to be maintained at lower RPM. Would the sails get you home? They would get you somewhere for sure but really limited to 90 degrees or greater relative to the wind. I am an ex sailor and like having sails onboard and use them a lot. We also have a jib and asymmetric spinnaker. They load up pretty good in 15 knots plus and push old girl along then but under 10 apparent are more in stabilizer mode. Regarding conversation of the 42 - the loads a rig put on the hull need to be understood. The boat loads up but does not significantly increase speed. Rigging, chain plates, spars etc are sizable for the modest amount of sail area. in my case they are pushing an 80,000# boat along. The rigging for the main mast is 10 mm. The shroud plates are sizable and are through bolted in solid grip in the hull. I don’t think that it is feasible to add this to the 42 and perhaps the funds involved would be better spent on a designed motor sailing vessel.

Good luck,

 

[Selidster]

Saw this on pinterest. Same sort of idea.