New Searunner 37 owner

[Skipper_Dan]

Hello, I just purchased a Searunner 37. Have not yet even seen it. It has an engine that is down. The reason I was able to get it. I am going to convert it to Electric drive. My Chrysler 26 Has an electric drive that I installed. 3kw motor mated to a 9.9 lower unit. This arrangement moves the boat with ease. I can do at least 6 kts. The sweat spot is 4kts. I see that the Searunner uses a 25 hp Universal 25 engine. This equates to a 10kw motor. I also see on the forum where a smaller outboard moves it 4kts. Just how much HP do I need to push a 37? I am never in a hurry. This will be direct drive to the original prop.

Skipper Dan S/V Popeye

[catsketcher]

I have a cat that is about the same size and weight as a Searunner 37. I have a 25 hp four stroke high thrust Yammie outboard. It is a great engine. So that could be a good starting point. I don't use full thrust for anything but manouvreing, and that only in the shortest of bursts - so you should be fine for an electric motor with less than 25hp.

Read through this huge thread too

https://www.cruisersforum.com/forums...ers-14322.html

cheers

Phil

[Mexican Hat]

Congratulations on the new boat.

The comment that caught my eye was about your converting a 9.9 outboard to a 3kw electric motor. Did you document that at all or have any information you can share?

I have two Suzuki 9.9's on my cat and after many issues with them, would like to convert them to electric. I have thought a little about it and it seems that a conversion should be relatively straightforward.

Thanks

[catsketcher]

Gday M Hat

Are you sure that you want to convert to electric? If it is a case of bad motors then you could consider Yamaha 9.9s. They are a very good engine. I am happy with the 25 as well.

I have a friend who is right into solar and electric. He is a top sailor and liveaboard. Yet even with all the solar his boat has and his desire to remove the ICE motors, he only removed one ICE. He now has a hybrid arrangement - one electric and one diesel.

It is a great setup - you should watch his videos

https://www.youtube.com/watch?v=vQzXQDQ2ym8

[Mexican Hat]

I'm just thinking about it at this point because I have other more urgent projects to finish, but yes, ultimately I want to replace the outboard power heads with electric motors. The Suzuki 9.9's have been nothing but a PIA, with multiple failures of electrical wiring and components.

On top of that Suzuki has made little provision for a decent dealer network and parts supply. I've had several dealers refuse to work on them because "it's not worth it, just go buy a new one". Many major components like starter motors are not available anywhere. And when they are available, the prices are insanely high. The RRP for a replacement starter is just under US$1,000...on a motor that costs $3,000 to buy complete.That's not a game I want to play, especially not after just 3 years of intermittent use.

The yamahas do have a reputation for reliability but don't work well for my application for a couple of reasons. I will watch the video, thanks. My loose plan is for a hybrid set up with a generator.

[Skipper_Dan]

Originally Posted by Mexican Hat

Congratulations on the new boat.

The comment that caught my eye was about your converting a 9.9 outboard to a 3kw electric motor. Did you document that at all or have any information you can share?

I have two Suzuki 9.9's on my cat and after many issues with them, would like to convert them to electric. I have thought a little about it and it seems that a conversion should be relatively straightforward.

Thanks

I mounted the lower unit to my hull. I installed a 3kw motor inside the hull. 60 volt 300 Ah life Po4 battery. Google Scott Masterson he can maybe help you convert an outboard.

Dan

[Skipper_Dan]

I found some build pics of my 37. About 100 plus the build manual. This should help quite a bit in the rebuild.

[Skipper_Dan]

Originally Posted by Mexican Hat

Congratulations on the new boat.

The comment that caught my eye was about your converting a 9.9 outboard to a 3kw electric motor. Did you document that at all or have any information you can share?

I have two Suzuki 9.9's on my cat and after many issues with them, would like to convert them to electric. I have thought a little about it and it seems that a conversion should be relatively straightforward.

Thanks

Smasterson2@gmail.com. he is the one who set up my motor. Kelly controls is the supplier. The 3 kw is the easiest and least expensive.

Skipperdan S/V Popeye

[Mark Johnson]

Originally Posted by Skipper_Dan

Hello, I just purchased a Searunner 37. Have not yet even seen it. It has an engine that is down. The reason I was able to get it. I am going to convert it to Electric drive. My Chrysler 26 Has an electric drive that I installed. 3kw motor mated to a 9.9 lower unit. This arrangement moves the boat with ease. I can do at least 6 kts. The sweat spot is 4kts. I see that the Searunner uses a 25 hp Universal 25 engine. This equates to a 10kw motor. I also see on the forum where a smaller outboard moves it 4kts. Just how much HP do I need to push a 37? I am never in a hurry. This will be direct drive to the original prop.

Skipper Dan S/V Popeye

The Searunner 37 trimaran needs at least 10 and preferably 20 hp at the prop. A diesel can put that out all day long. It will move it at 6.5 - 7 knots, with light winds. 20 knots on the nose, and it might only go 4 - 5 knots.

Unless you only want enough range to leave the dock, like 1 mile, the amount of battery power you need for a decent range, is too much weight for a tri.

An electric motor has a very limited range at full output, but if you motor at 1/4 output, the speed drops a knot or two, while range goes up 300 - 400%.

This means you might only have 5 - 10 hp at the prop, which will not push you into a stiff breeze at all.

The boat is simply not the same, if you add 1,000# of batteries to it, and it eats up your limited payload.

If you don't have that much battery reserve, that's ok as long as you only use it to leave the dock, and return to your slip. It is a bad idea for cruising, where hours of motoring, in inlets, up rivers, the ICW, or motorsailing all day... are called for. Doing these things require a much larger motor, running on 1/4 throttle, and a huge battery bank. Even then, the range can't compare.

Caveat:
Also... these self built boats vary all over the place. Some, the best 5%, are WEST system, with LP paint over gray primer, and kept a dry bilge, always!

Most, however, had neither WEST system, nor LP paint, and kept water in the plywood bilge. You need to go see the boat, and discern which of these you have, before making any choices.

(All based on 56 years as a shipwright, and cruiser on my boats in between projects).

BTW... I do use an E Propulsion OB (Spirit +)motor on my dinghy, and it works great, albeit slowly, and I charge it with the solar on our Searunner 34. I love it!

Were I to try to solar charge a large battery bank pushing the mothership, however, I might have to sit at anchor for a month!

[Skipper_Dan]

Originally Posted by Mark Johnson

The Searunner 37 trimaran needs at least 10 and preferably 20 hp at the prop. A diesel can put that out all day long. It will move it at 6.5 - 7 knots, with light winds. 20 knots on the nose, and it might only go 4 - 5 knots.

Mark Thanks for the reply, I have had my Chrysler 26 set up with electric for quite a few years. It is a 8000# mono hull so I am not sure how that equates to a Tri. I found the manual in the boat as I was cleaning. After reading through it Jim Brown suggests no motor at all, and 6 hp would move it around. I am sitting now with basically no motor (Why I was able to purchase it). I have been sailing down the Mississippi with the Chrysler on electric. WI to St Louis. I can generally go 12 hrs. am setup with 3kw 60v motor 1000 watts solar and 300 Ah of LifePo4 cells @60v. I have a 3600 watt generator as well as a 6 hp Nissan outboard. Which Jim says is the max amount you can add as an outboard. Now that I have more room for solar I am going to add one more 500w panel for the motor. The house also has 300 Ah LifePo4 and 400 watts of solar. I am a liveaboard so getting someplace is not critical. I am sure that the 3kw is going to be on the small side but it moved the 26 with ease. I can at some point upgrade to a 10kw motor if I think I need to. 10 kw is the same as 25 to 30 hp. with the Nissan and the 3kw I have 12hp.

I thank you for your help with the Searunner. As I see there is a learning curve to sail them. I am getting the Universal 25 working hopefully this week. I need to move it to The Boat yard in Charleston in about a month to haul it out and do a bottom job on it.

Thanks, Skipper Dan S/V Popeye

[catsketcher]

Be careful with Jim's ideas on motors. He was writing the manual in the late 60s and early 70s when motors were totally different from today. Modern motors are much lighter, much smoother and much quieter than today. As for sizes - be careful about going small. Jims own Searunner 31, which is about half the boat compared to the 37 has a 9.9 hp motor. So trying to get the 37 around in any wind with something like a 3kw motor will just not work in a range of conditions that you find cruising.

Like I said before - a 25 hp outboard would be a good size for your 37. Any smaller and you lose safety margins when the wind comes in at night and you have to pull the anchor up and move or you lose the boat on the rocks. You can't argue with reality when it hits you and your boat in the face.

Goimng total electric for normal cruising just doesn't work. I went through about 300 litres of petrol in 3 years of cruising - it very little as we sailed almost all the time. Yet there were many times when we motored 40 miles when needed - at 7 knots. There was also the time we motored almost 180 miles across Bass Strait. Both situations are required for safe cruising and both cannot be undertaken by a full electric boat. Electric does not work for real cruising. Go ahead if you like, but my mates who did this took out their mono with electric only, took out the electric after about a year and went back to diesel. There is no way I would ditch ICE for electric only.

[double u]

"... I just purchased a Searunner 37. Have not yet even seen it..."

no comment...

[Cavalier MK2]

I use a Yamaha 9.9 for most cruising and it will push the Nicol into winds well past 20 at a good clip. I did get a Tohatsu Sailpro 6 for a summer economy motor and it has been entertaining. It can get 5+ knots with a dirty bottom in a calm but will slow as wind on the nose builds. We got stuck with a deadline chuffing into 20 knots with higher gusts and it would slow to 1-2 knots. The solution was motor sailing, with some jib unrolled we were back up to 4-5 knots. We weren't sailing because We had been testing a new main but didn't have the reefing rigged yet.

Economy wise it is very frugal, seems like half the gas of the 9.9. I'm pondering one of the bigger 15-20 Tohatsu motors with fuel injection as it isn't heavier than the 9.9 and they have a good assortment of props.

I'm fine sailing without motors if you have the time, seems like a electric to clear the harbor fits in that category but I'd hate to need to get anywhere.

[Skipper_Dan]

Originally Posted by double u

"... I just purchased a Searunner 37. Have not yet even seen it..."

no comment...

I did finally get to se it. it was a very trying two weeks. I am happy with the decision to purchase it. It fits my profile very well. On the other hand it will be a lot of work, but nothing I have not done before. It is sad how people let boats get so bad. It took two weeks of cleaning and I'm still not done.

Skipper Dan S/V Popeye

[Skipper_Dan]

Originally Posted by Cavalier MK2

I use a Yamaha 9.9 for most cruising and it will push the Nicol into winds well past 20 at a good clip. I did get a Tohatsu Sailpro 6 for a summer economy motor and it has been entertaining. It can get 5+ knots with a dirty bottom in a calm but will slow as wind on the nose builds. We got stuck with a deadline chuffing into 20 knots with higher gusts and it would slow to 1-2 knots. The solution was motor sailing, with some jib unrolled we were back up to 4-5 knots. We weren't sailing because We had been testing a new main but didn't have the reefing rigged yet.

Economy wise it is very frugal, seems like half the gas of the 9.9. I'm pondering one of the bigger 15-20 Tohatsu motors with fuel injection as it isn't heavier than the 9.9 and they have a good assortment of props.

I'm fine sailing without motors if you have the time, seems like a electric to clear the harbor fits in that category but I'd hate to need to get anywhere.

Thanks for the info Cavalier, I am not a novice to the Electric drive. I have been using one for 10 years. It has never let me down. The trick is to have it set up correct. I have enough battery to go 12 hrs. I have or will have shortly enough solar to charge up rather quickly. With a generator onboard I can do 25 amps to the motor until I run out of gas. The 3600w generator will last 8 hrs charging at 20 amps on 2 gallons of gas. I also will have the Nissan 6 hp attached to the stern for even more power or safety, that's 12 hp with the electric 3kw motor running. The best part about it is the liveaboard aspects which you do most of the time. I have almost unlimited power without running the generator. My setup is very close to the video at the beginning of this thread that someone posted. If I have to I will go to a 10kw motor.

Skipper Dan S/V Popeye