Boom pulpit question

I am building a 2 person trimaran, sit inside, foot pedal steering. I like the Hobie AI design of the sail furling around the mast and plan on a mast that is 24 foot high, unstayed, and plan to have a furling drum at the base of the mast, with a continuous line around the mast/drum to instantly furl down to the desired amount of sail for the wind conditions.

The Hobie AI does not have a boom, and it is my understanding that the addition of a boom gives you alot better sail shape (I guess...not sure). I have rigged up some pvc to simulate the boom/mast connection, rather like the Sea Pearl boats, but there is too much friction to allow easy furling of the big mast.

But, I have seem a small trimaran at Cedar Key, Fl that had a separate fixed pulpit for the boom. This pulpit is just behind the mast, and is perhaps eye level as you are seated, allowing the boom to go over your head without hitting you as you tack.

Can anyone say whether having a boom pulpit is good or bad? (I had heard from someone that some of the really big cruising cats have this boom pulpit)

Thanks for allowing a newbie to ask questions

 

Not sure of the meaning of the tem boom pulpit. In any case a sail with a boom provides a range of sail camber and tuning adjustments not possible with a boomless sail. In addition, a boom is a definite advantage when sailing off wind unless you want to be bothered with a whisker pole or other gadgetry.

To be sure a low boom will bash your head if you become unwary. Experienced sailors have no problem with that.

 

Freestanding main boom

I'm not familiar with the term "boom pulpit" either but here is a free standing boom designed by Garry Hoyt that might work for you:

click on image for larger view-

 

There is nothing wrong with a boom pulpit. The Hoyt boom is an easier implementation.

If anything is 'wrong' with your plan I would point a finger at the roller furling mast you plan. A few low performance manufactured sailboats have used roller furling masts to simplify the appearance of their product but the design brings many limitations.
-high stress low friction bearing to maintain
-fatigue loading on the mast -all materials (exp steel and titanium) have limited fatigue life
-limited to vertical battens (low value)
-poor reefing of square (or roachy) main -you want the center of effort to move lower
-poor reefed sail shape -with the first turn your sail is essentially flat cut
-mast limited to unstayed cylindrical -sacrificing shape and structure

Trimarans are complicated designs and builds that are worth the effort because of their high performance. A roller furling mast gives up most of that performance and it is pretty hard for an amateur to even do a decent one -the mast needs to be tapered carbon fiber.

Take a look at roller furling booms on simply supported masts. They do everything better than the rolling mast and you can save money on existing high performance or used parts and sails.

 

Just as a point of clarification, this so called boom pulpit I saw in Cedar Key was simply a strong wood post, attached to a bulkhead beneath the deck, going thru the deck and rising up above eye level, between you and the mast itself. The boom connected to this block of wood. For lack of a better term, I called it a boom pulpit.

 

Tri

When you get a chance I'd like to hear more about your boat-sounds very interesting. Any pictures?

 

There are some unfavorable geometric implications with the use of a "boom pulpit" or other arrangement that places the center of boom rotation at some distance from the luff of the sail.

Mast roller reefing moves the CE progressively forward which will have an effect on steering. Worst case is serious lee helm. Mast roller furling is probably a good idea. It is quick and easy. Stores the sail neatly and wrinkle free too. The deal is off if the sail has roach which will almost surely require battens. Please note the above difference between reefing and furling.

 

This arrangement isn't all that uncommon among gaffers and other antique designs and doesn't place the gooseneck very far aft of the mast, at least not so much as a traditional gooseneck. It's an added convolution on a tabernacle mast boat, assuming the tabernacle is well designed. I see no advantage to this setup, unless towing or storage needs require the boom crotch to be lower than would be typical on a tabernacle boat.

As described by the OP, the arrangement would be difficult do well, unless everything is fairly small and light. Luff furling and reefing have been around a long time, but for the reasons listed often isn't very desirable, particularly on performance oriented craft.

Common methods of reefing and furling, aren't terribly difficult to live with. What is the point of a different arrangement? What is objectionable about the more common methods of dealing with these issues?