Alcanboats Forum

Perhaps some of you 370 owners know what the design weight of my alcan 290 boat could be, or you know of someone who has one. I would like to avoid the lift out of the water and the drive over to a weight scale. I need this to do calculations for required H.P. and see what it would take to get it onto plane.

Robert Stork

Hi Robert,
Nice to talk to you. I don't know the 290 design weight, but we have twin 1997 Mercruiser 4.3 LX's V6's @ 190 H.P. each and we plane @ 3200 rpm per engine, doing 16 to 19 knots and W.O.T. to 30 knots +. We has a wet weight of 18,000 lbs. Also most marina lifts have a weight reading capability. When ever we do a haul out I ask how much we weight. You know how fast a boat can put on weight with all that boat stuff building up. Every year I remove "stuff" that is gas consuming and speed removing. Our rule is, "if we have not used it in the last 6 months, out it goes". Good luck on your project.

Patrick

Hi Robert,

Another non-answer since I also do not have factual info on the weight of the 290. My knowledge of the Alwest 370 numbers is similar to the info from Eboness. The original brochure says 11,500. My ownership papers say 12,000 (but I have a flybridge) and the crane operator tells me 16,000 (with tanks full and all that other "necessary" stuff crammed into every storage space) I have the original engines and am only carrying 100 gal fuel, so this may be why my numbers are less than Eboness.
So . . . . a little proportional math would tell me that a 290 would weigh roughly 12,000 lbs wet. (It will be interesting to see if I am even close when you get an actual weight measurement)

Rob

I have not found much Alcan 290 info anywhere. I will keep asking around, but in the meantime I have a couple of suggestions.

1 - Fill us in on some of the details about your boat (what engines did it come with? Was there a generator?) I am missing even basic info in my "Models" section. For instance, I don't know the beam and some of the other physical details.

2 - When I did my own repower, I did a fairly detailed weight inventory as I knew I would be removing the generator (380lb) and replacing the light-ish I-6 (~650lb) with a heavier V-6 (~900lb). I ended up estimating the weight of the hull (minus stuff in engine compartment) at about 9000LB. If we said that there was another 1000lb of stoves, fridges, toilets, etc., then the 370 hull is probably about 8000lb. Scale that by 29/37 and you get about 6300lb. Assuming you have the same 1000lb of fridge and stove, but perhaps a pair of 500lb Inline-4 engines and 200lb of batteries, but no generator, you probably come out at a dry weight of around 9,000 lb. This would align with the 11,500 to 12,000 lb published weight for an Alcan 370. Now add reality which includes ~50 gal of water (500lb) and 100 gal of fuel (600lb) and possibly full 30 gal holding tank (300lb) and 1500lb of those cute little brass signs that everyone seems to give to boaters and you probably have a realistic running weight of 12,000lb. I am kidding about the signs, but these boats are 35 to 40 years old and have a lot of rotten wood and questionable (heavy) repairs and modifications, so I will still allocate a fair bit of weight to that kind of stuff.

I will dig up my weight planning spreadsheet if you are interested. It would provide a little more accurate weights of some of the inventory.

BTW, if you have Volvo Penta engines, they have published brochures on their web site for all of their out-of-production drives.

hope this helps.
David

Thanks everyone,

We have been cruising.

our boat, Little Blue Whale, has a 225 HP v-8, OMC with drive. We have no gen. but probably too much stuff. I will use all the advice to rough guess. i tend to think wet weight (with two adults and two kids) at about 11,000 lbs.

when i rev. up to 4000- 4500 rpm she almost wants to get out of the water but then starts digging in at the stern.

Robert Stork

Robert, or anyone else, did you ever get your 290 on plane? Mine almost does and then, as you say, bogs down in the stern, so I was wondering if trim tabs would help.

The drawing on the 290 brochure looks like it is planing. There is an old article from BC on a 37 that planed with the same engines as mine: twin 155 OMC.

Properly functioning twin 155 HP engines should bring a 290 up on to plane. The flat V Alcan hull does not plane like a dinghy or a modern deep V hull. It must maintain an "angle of attack" which makes it look like the stern is too low. Have a look at the pictures of Buster at speed in the registration section of the alcan website. Trim tabs are more likely to slow you down than to get you up on plane. In the tech section, see the articles on hull dynamics for more info on this.

Rob

When we had Our Cottage we installed tabs to see if they would bring up the stern....NOT! However there was a marked improvement in slow speed handling.

Joe

Hi Joe,

Good to hear from you! Hope all is well.
Exactly right . . . putting on the brakes to try and lift the back end of an Alcan will not help it to reach planning speed
What was the slow speed handing improvement ? Side to side balance ??

Rob

Hi Rob, all is well. The improvement was in slow straight line handling. The tabs helped in the drag into locks, especially in crosswind conditions.

Joe

RE Rob's post:

"Properly functioning twin 155 HP engines should bring a 290 up on to plane. The flat V Alcan hull does not plane like a dinghy or a modern deep V hull. It must maintain an "angle of attack" which makes it look like the stern is too low. Have a look at the pictures of Buster at speed in the registration section of the alcan website. Trim tabs are more likely to slow you down than to get you up on plane."

Has anyone brought a 290 on plane with twin 155 HP's? Like others who wrote here, it feels like it is about to plane, except for the stern, and YES I've also thought that trim tabs might do the trick - now I know they won't.

And PATRICK, wow! How did it handle on plane with your 190's ?

It is always interesting to see how many "dormant" discussions comes back to life "mid-winter" when we are all thinking about getting back out on the water ! I would suggest that you study the graph at the very end of David's info at http://www.alcanboats.com/alcan_hull_dynamics.htm.
Plot this same speed vs RPM for your boat and this will tell you if you are actually planing. If there is a "knee" in your graph of speed vs RPM, the boat is getting up on plane, even if you think it is not. Another way to measure this is If you can reach a speed above about 13 knots, the boat must be on plane. A third way to judge this is by looking at the transom. If it is entirely dry . . . all the way down to the drain plug . . . the hull is planing (or at least almost planing). Stern down is the "attack angle" that has to be maintained to get an Alcan hull up on plane.

Rob