Cobaltchat.com

Going to be ordering a R7 Surf need your thoughts for engine selection

please see the prop chart provided by cobalt and let me know your thoughts, in my opinion the 380hp it the best selection for the surf boat

Currently the boat is going to be optioned as follows

WSS 3 color custom
Bow and Cockpit tonneau cover
Plat. Sound w/ transom spkrs
Rudder Indicator
Transom Stereo Remote
Transom Tilt Switch
Folding w/ bimini arch (manual not electric)
Soft Trac Mat throughout
Windlass
Docking Lights
Std. porta potti
Portal Light

Let me know your thoughts on engine selection along with any other options we may need. I do not plan on using the bathroom unless it is an emergency.

Thanks

Z

Hey Z. Welcome to the cobalt chat forum. So glad you found us!

380 hp would be the minimum I would order after owning that horse power and greater. It is certainly a sweet spot based upon price; Power requirements; and resale value. Of course with an engine putting out that kind of horsepower, to me captain's call is a must!

By the way, I'm curious if you have ever driven a boat with a forward Drive.

Those are great options you have chosen. They would all be on my short list as well. Another option I would consider are trim tabs. They work very well to balance your load in a deep vee boat. Plus most of your weight will most likely be on the port side due to the seating arrangements and a starboard rear entry.

Can't wait to see pictures of her once you take delivery down the road. Once again welcome aboard !

Welcome from Oklahoma!

Ytmsn thanks

Aslan

Yes I have driven the forward drive it performs very much the same with its own little quirks such as going slow The boat turns more from the centerpoint then the rear
And comparing the prop charts it looks like the 380 hp planes faster has the same gear ratio of the 350 horse but can turn higher rpm. I am assuming the boats were tested on different days and different wind etc thus the reason the 380 chart is showing it going slower however simple math should put the 380 going faster if all conditions are the same.
Also if I have done my homework correctly the 350hp is a 5.3 liter where the 380 is a 6.2

Welcome again from Oklahoma! I went through this same process a few months ago. I was torn between the 380 and the 430 but in the end I couldn't justify the extra cost of the 430 based on the performance increase. Couple of things you can't get the trim tabs with the surf model due to the surf tabs. I am concerned about this but we will see how it does. Also, the transom remote comes standard with the Platinum sound package which is what I ordered. I expect to take delivery of mine in the next few weeks as it should be just about finished being built. Just so you know you can order any of the R7 graphic packages with the Surf model. It's a fun process and looking forward to hearing about the process of yours. If you have any questions about the options feel free to ask as I feel like I have been over and over every option.

Did you look at the new folding (non electric) rotating sunshade? I think it looks pretty sharp!

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I am assuming the boats were tested on different days and different wind etc thus the reason the 380 chart is showing it going slower however simple math should put the 380 going faster if all conditions are the same.
Also if I have done my homework correctly the 350hp is a 5.3 liter where the 380 is a 6.2

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Yes...curious why that one RPM number is missing in your chart. In any event, I don't think you will regret the "sweet" spot of the 380 based upon the information I posted earlier.

I forgot, the R7 Surf comes with the trim tabs as standard equipment. They are used for both surf wave production as well as ride balancing.
Some other options to strongly consider are the motorbox actuator and the dual battery switch. IMHO, the dual battery switch with dual batteries is a necessary option these days. That way you can run your music, devices, pumps, etc. and if one battery dies, you just switch to the other. Great insurance.

What colors have you chosen?

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Those #'s on the Volvo look wonky to me. All around the same top end with that much difference to plane?

Based on that I'd say you have it nailed.

Otherwise I'd say 430 Fwd in a landslide if you can swing it.

Welcome to the forum btw.

liquid wrote: Tue Nov 07, 2017 2:20 pm Those #'s on the Volvo look wonky to me. All around the same top end with that much difference to plane?

Based on that I'd say you have it nailed.

Otherwise I'd say 430 Fwd in a landslide if you can swing it.

Welcome to the forum btw.

Agreed Liquid.
Believe it or not, Z, the 350 HP, 5.3 liter weighs 24 pounds more than the 380 HP, 6.2 liter!

Below are the Volvo Penta specs for the 5.3 and the 6.2 liter. The specs are including the weight of the DP outdrive vs the FwdDrive but that will not change anything for comparison purposes. (btw, the 6.2 380 shows a horse power number as 280--this is a typo in the Volvo Penta literature)

Again, the 380 horse (or the 430 if you can convince the wife ) is the sweet spot.

If you want to calculate a rough top speed in KNOTS, just click below. I would use a constant of 180-200 for this type of hull with a forward drive. To convert the answer to MPH, just multiply your answer by 1.15. With a 6,676 lb hull-engine-and drive weight, I come up with about 49mph on the low end and 54 mph on the higher end.
http://www.go-fast.com/boat_speed_predictions.htm
...or use this formula...Speed (knots) = C / {sqrt(weight/hp)} )

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Chanting now... 430! 430! 430!

You guys are great at spending other people's money! I know I spent a lot more after all of your help building out my R7!

Soonerfan wrote: Tue Nov 07, 2017 2:54 pm You guys are great at spending other people's money! I know I spent a lot more after all of your help building out my R7!

Glad we could help!

Liquid

why the 430 it has the worst time to plane out of all the choices (most likely due to gearing) This is a family boat with forward drive for water sports. if i was wanting speed i would be looking at the DP drive not FWD drive.

NE Zack wrote: Tue Nov 07, 2017 3:55 pm Liquid

why the 430 it has the worst time to plane out of all the choices (most likely due to gearing) This is a family boat with forward drive for water sports. if i was wanting speed i would be looking at the DP drive not FWD drive.

Because I don't believe that plane time... I could be wrong (and am frequently according to Mrs. Liquid) but the times and MPH look off to me.

That's a big boat and you can never go wrong with more power. I understand family boat and am all in on the Fwd drive. If I was going new right now it'd be the R3 Surf no question about it.

Again, based on those numbers and your described need the 350 is right in that wheelhouse. If you're asking what I'd put in that build it's the 430. Better to have and not need than to need and not have. Just my two cents.

Z, bottom line, you will be fine with the 380 hp 6.2. The extra $5,224 over the 350 hp is worth it both in power and resale.
Cheers.

I think the 380 will be fine - if you're going to spend a few extra bucks, get the duo prop!