The Boating Forum - Seagull Catamarans

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View Full Version : Seagull Catamarans

03-17-2010, 11:56 AM
I'm looking at a 19 foot Seagull cat with a 75 HP Mercury. I know nothing about that brand of cats.

Can someone help out here? Is this a solid boat? is there any wood used? Any issues?

Thanks in advance for your help, this forum is a great resource for a new boater like me.


03-17-2010, 03:05 PM
There is no 19' Seagull, they were 16', 18' & 20'. Don't know much about the 16'. The 18' came with a 70hp on it and the 20' typically came with twin 70 hp's on it, although there were a few 20's with a single and I believe most of them are 90-115's. The boats are made with wood and earlier models are very suspect (97-98) with poor quality control. It seems that the '99-'01 models had better quality control. As with any boat, a survey and a compression check are good ideas. The 18' is a great little boat, but I feel it was severely under powered with the 70. It had a cruise in the teens and a WOT in the low-mid 20's. It's a great bay boat and I would have no problem taking a well maintained one 20-25 miles offshore in smaller seas. It would handle 4'ers, but I definately wouldn't go out in them but feel safe comming home in them. 5'ers are the upper limit of the comfort zone. The 20's have a wider beam and can handle larger seas, although I would not consider them serious offshore boats. Again, comfortable in 2-3's. All in all, they are great boats. Just need to check for any issues like you would with any other used boat and use it for it's intended purpose and you won't regret buying one. By the way, for an 18', I think 3 good sized men would be a comfortable limit and the 20' is good for 4 good sized men.

03-21-2010, 12:41 PM

First, welcome to THT. You are right, it is a great resource.

I missed this thread for a few days, and wasn't sure you would see this reply so I have sent you a PM. (That's "Private Message." To view it, at the top right of each page you will see the "Welcome Box," where it should say "Welcome seaisle" (This assumes you are logged in.) Just below that, you should see "Private Messages:" Just click that to view the message.)

The pix below are my Seagull 19/20 (it gets called both.) Seagull called it the 19, but since it is just short of 20 (around 19 ft 10 inches) it came to be known by many as the Seagull 20.

Dave Dillon
06-09-2010, 04:56 PM
I have just purchased a 2001 20 seagull with a single Honda 130. with only 100 hours on it. Having problems with water shooting up between the lower unit and the transom seems like a drag on the performance, I can onley get 25 k wide open. The motor seems set too low, it's at the lowest pin. It has a cavatation plate which i removed and didn't see any difference. When the plate was on it was so far below the water at 20k it could not be seen. Another post stated that it should be at the surface. Can you shed any wisdom on this ?
Dave Dillon

06-09-2010, 05:16 PM
The Seagull 20 with a single was renowned for it's pitiful performance. Having a heavy arse Honda 130 must be exacerbate the performance issues. If you raise the engine you will find it has cavitation issues (especially in turns). It perfoms much better with twins. Maybe trade your 130 for twin 65s. :)

06-09-2010, 05:26 PM

I have the same boat (1997) with a Honda 90. You should not be experiencing that "water spout" in front of the motor. Several thoughts.

First, the one you raise. When you said you removed the "cavitation plate" I assume you meant an add-on such as a Doelfin or similar, right? (Since you can't remove the REAL cav plate, which is part of the motor's lower unit. On mine, my motor's cav plate is almost exactly even with the lowest point on the keels of the sponsons, the bottom of the v's in other words. (Where you can see the drain plugs on the stern of mine.) When planing it runs just slightly below water level. (The cav plate, by the way, is the largest of the three flanges on the lower unit, and is the bottom one. It's clearly visible in the pic of my motor.) My motor is mounted in the second hole from the top, and I would think that if yours is as you say, it is too low.

Second, I have linked a picture below. Note just below the motor and below the transom, on the "bulge" in the tunnel which is to smooth conditions in the tunnel for single engine cats, there is a ninety degree stainless plate. It is a little hard to make out in the pic (the arm of the lift sort of blends in with it,) but you can clearly see the four bolts which mount it. AFAIK, that was a factory item, but anyway, its exact function is to kill splash which might come from below as you are describing. Does your boat have such a piece? By 2001, a different maker was building the Seagulls and may have left that piece off. It is easy to add.

Third, you don't state your RPM's at wide open throttle, but the spec on the 90 is 5000-6000, and I believe the 130 is the same, or very close. My 90, with full gas and just me in the boat, will deliver a top speed of around 35 (MPH, not knots) at about 5650 RPM's. Yours is way off. Besides engine height, prop type is an issue. This boat does poorly, generally, with a three blade prop. Do you know what you are running?

I guess I'd first try to get the motor at the right height, and I'm sure that will up your top speed. If that doesn't stop the "spout" then if you don't have the little SS bracket I'm referring to I'd consider adding one. Last would be the prop.

Well, enough for now. Let me know.

06-09-2010, 05:31 PM

BTW, didn't see the first reply to you, since I was typing mine. Just ignore Onewolf's well-intentioned but not quite correct reply. Like about half the world, he is confusing the "true" Seagull boat with another line the Seagull factory made called the Nautico. The Seagull was never offered with twins and never made with a transom that would take twins. Performance is not at all "pitiful".

Regarding "the heavy-arse motor" etc., the Seagulls came from the factory with only two standard rigged power options, the Honda 90 and the Honda 130. The boat was designed for them.

Cavitation CAN be an issue, but with proper motor height and proper prop, it is a non-issue.

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